Kohar Jones, MD

PRACTICE CHANGER
Discuss cell-free DNA testing when offering fetal aneuploidy screening to pregnant women.^1,2

Strength of recommendation
A: Based on multiple large, multicenter cohort studies.^1,2

A 28-year-old woman (gravida 2, para 1001) at 10 weeks’ gestation presents to your clinic for a routine first-trimester prenatal visit. Her first child has no known chromosomal abnormalities, and she has no family history of aneuploidy. She asks you which tests are available to screen her fetus for chromosomal abnormalities.

Pregnant women have traditionally been offered some combination of serum biomarkers and nuchal translucency to assess the risk for fetal aneuploidy. Cell-free DNA testing (cfDNA) is a form of noninvasive prenatal testing that uses maternal serum samples to conduct massively parallel sequencing of cell-free fetal DNA fragments.

It has been offered to pregnant women as a screening test to detect fetal chromosomal abnormalities since 2011, after multiple clinical studies found high sensitivities, specificities, and negative predictive values (NPVs) for detecting aneuploidy.^3-6 However, until 2015, practice guidelines from the American Congress of Obstetricians and Gynecologists (ACOG) recommended that standard aneuploidy screening or diagnostic testing be offered to all pregnant women and cfDNA be reserved for women with pregnancies at high risk for aneuploidy (strength of recommendation: B).⁷

CARE (Comparison of Aneuploidy Risk Evaluation) and NEXT (Noninvasive Examination of Trisomy) are two large studies that compared cfDNA and standard aneuploidy screening methods in pregnant women at low risk for fetal aneuploidy. Based on new data from these and other studies, ACOG and the Society for Maternal-Fetal Medicine (SMFM) released a new consensus statement in June 2015 that addressed the use of cfDNA in the general obstetric population. The two groups still recommend conventional first- and second-trimester screening by serum chemical biomarkers and nuchal translucency as the firstline approach for low-risk women who want to pursue aneuploidy screening; however, they also recommend that the risks and benefits of cfDNA be discussed with all patients.⁸

Continue for study summaries >>

STUDY SUMMARIES
CARE was a prospective, blinded, multicenter (21 US sites across 14 states) study that compared the aneuploidy detection rates of ­cfDNA to those of standard screening. Standard aneuploidy screening included assays of first- or second-trimester serum biomarkers with or without fetal nuchal translucency measurement.

This study enrolled 2,042 pregnant patients ages 18 to 49 (mean, 29.6) with singleton pregnancies. The population was racially and ethnically diverse (65% white, 22% black, 11% Hispanic, 7% Asian). This study included women with diabetes, thyroid disorders, and other comorbidities. cfDNA testing was done on 1,909 maternal blood samples for trisomy 21 and 1,905 for trisomy 18.

cfDNA and standard aneuploidy screening results were compared to pregnancy outcomes. The presence of aneuploidy was determined by physician-documented newborn physical exam (97%) or karyotype analysis (3%). In both live and nonlive births, the incidence of trisomy 21 was 5 of 1,909 cases (0.3%) and the incidence of trisomy 18 was 2 of 1,905 cases (0.1%).

The NPV of cfDNA in this study was 100% (95% confidence interval, 99.8%-100%) for both trisomy 21 and trisomy 18. The positive predictive value (PPV) was higher with cfDNA compared to standard screening (45.5% vs 4.2% for trisomy 21 and 40% vs 8.3% for trisomy 18). This means that approximately 1 in 25 women with a positive standard aneuploidy screen actually has aneuploidy. In contrast, nearly 1 in 2 women with a positive cfDNA result has aneuploidy.

Similarly, false-positive rates with cfDNA were significantly lower than those with standard screening. For trisomy 21, the cfDNA false-positive rate was 0.3% compared to 3.6% for standard screening (P < .001); for trisomy 18, the cfDNA false-positive rate was 0.2% compared to 0.6% for standard screening (P = .03).

NEXT was a prospective, blinded cohort study that compared cfDNA testing with standard first-trimester screening (with measurements of nuchal translucency and serum biochemical analysis) in a routine prenatal population at 35 centers in six countries.

This study enrolled 18,955 women ages 18 to 48 (mean, 31) who underwent traditional first-trimester screening and cfDNA testing. Eligible patients included pregnant women with a singleton pregnancy with a gestational age between 10 and 14.3 weeks. Prenatal screening results were compared to newborn outcomes using a documented newborn physical examination and, if performed, results of genetic testing. For women who had a miscarriage or stillbirth or chose to terminate the pregnancy, outcomes were determined by diagnostic genetic testing.

The primary outcome was the area under the receiver-operating-characteristic (ROC) curve for trisomy 21. Area under the ROC curve is a measure of a diagnostic test’s accuracy that plots sensitivity against 1 – specificity; < .700 is considered a poor test, whereas 1.00 is a perfect test. A secondary analysis evaluated cfDNA testing in low-risk women (ages < 35).

The area under the ROC curve was 0.999 for cfDNA compared with 0.958 for standard screening (P = .001). For diagnosis of trisomy 21, cfDNA had a higher PPV than standard testing (80.9% vs 3.4%; P < .001) and a lower false-positive rate (0.06% vs 5.4%; P < .001). These findings were consistent in the secondary analysis of low-risk women.

Both the CARE and NEXT trials also evaluated cfDNA testing versus standard screening for diagnosis of trisomy 13 and 18 and found higher PPVs and lower false-positive rates for cfDNA, compared with traditional screening.

WHAT’S NEW
Previously, cfDNA was recommended only for women with high-risk pregnancies. The new data demonstrate that cfDNA has substantially better PPVs and lower false-positive rates than standard fetal aneuploidy screening for the general obstetric population.

So while conventional screening tests remain the most appropriate methods for aneuploidy detection in the general obstetric population, according to ACOG and SMFM, the two groups now recommend that all screening options—including cfDNA—be discussed with every woman. Any woman may choose cfDNA but should be counseled about the risks and benefits.⁸

Continue for caveats >>

CAVEATS
Both the CARE and NEXT studies had limitations. They compared cfDNA testing with first- or second-trimester screening and did not evaluate integrated screening methods (sequential first- and second-trimester biomarkers plus first-trimester nuchal translucency), which have a slightly higher sensitivity and specificity than first-trimester screening alone.

Multiple companies offer cfDNA, and the test is not subject to FDA approval. The CARE and NEXT studies used tests from companies that provided funding for these studies and employ several of the study authors.

Although cfDNA has increased specificity compared to standard screening, there have been case reports of false-negative results. Further testing has shown that such false-negative results could be caused by mosaicism in either the fetus and/or placenta, vanishing twins, or maternal malig­nancies.^8-10

In the CARE and NEXT trials, cfDNA produced no results in 0.9% and 3% of women, respectively. Patients for whom cfDNA testing yields no results have higher rates of aneuploidy, and therefore require further diagnostic testing.

Because the prevalence of aneuploidy is lower in the general obstetric population than it is among women whose pregnancies are at high risk for aneuploidy, the PPV of cfDNA testing is also lower in the general obstetric population. This means that there are more false-positive results for women at lower risk for aneuploidy. Therefore, it is imperative that women with positive cfDNA tests receive follow-up diagnostic testing, such as chorionic villus sampling or amniocentesis, before making a decision about termination.

All commercially available cfDNA tests have high sensitivity and specificity for trisomy 21, 18, and 13. Some offer testing for sex chromosome abnormalities and microdeletions. However, current cfDNA testing methods are unable to detect up to 17% of other clinically significant chromosomal abnormalities,¹¹ and cfDNA cannot detect neural tube or ventral wall defects. Therefore, ACOG and SMFM recommend that women who choose cfDNA as their ­aneuploidy screening method also be offered maternal serum alpha-fetoprotein or ultrasound evaluation.

Continue for challenges to implementation >>

CHALLENGES TO IMPLEMENTATION
cfDNA testing is validated only for singleton pregnancies. Clinicians should obtain a baseline fetal ultrasound to confirm the number of fetuses, gestational age, and viability before ordering cfDNA to ensure it is the most appropriate screening test. This may add to the overall number of early pregnancy ultrasounds conducted.

Counseling patients about aneuploidy screening options is time-consuming and requires discussion of the limitations of each screening method and caution that a negative cfDNA result does not guarantee an unaffected fetus, nor does a positive result guarantee an affected fetus. However, aneuploidy screening is well within the scope of care for family practice clinicians who provide prenatal care, and referral to genetic specialists is not necessary or recommended.

Some patients may request cfDNA in order to facilitate earlier identification of fetal sex. In such cases, clinicians should advise patients that cfDNA testing also assesses trisomy risk. Patients who do not wish to assess their risk for aneuploidy should not receive cfDNA testing.

Finally, while cfDNA is routinely recommended for women with pregnancies considered at high risk for aneuploidy, many insurance companies do not cover the cost of cfDNA for women with low-risk pregnancies, and the test may cost up to $1,700.¹² The overall cost-effectiveness of cfDNA for aneuploidy screening in low-risk women is unknown.

References
1. Bianchi DW, Parker RL, Wentworth J, et al; CARE Study Group. DNA sequencing versus standard prenatal aneuploidy screening. N Engl J Med. 2014;370:799-808.
2. Norton ME, Jacobsson B, Swamy GK, et al. Cell-free DNA analysis for noninvasive examination of trisomy. N Engl J Med. 2015;372: 1589-1597.
3. Chiu RW, Akolekar R, Zheng YW, et al. Non-invasive prenatal assessment of trisomy 21 by multiplexed maternal plasma DNA sequencing: large scale validity study. BMJ. 2011; 342:c7401.
4. Ehrich M, Deciu C, Zwiefelhofer T, et al. Noninvasive detection of fetal trisomy 21 by sequencing of DNA in maternal blood: a study in a clinical setting. Am J Obstet Gynecol. 2011;204:205.e1-11.
5. Bianchi DW, Platt LD, Goldberg JD, et al; MatERNal BLood IS Source to Accurately diagnose fetal aneuploidy (MELISSA) Study Group. Genome-wide fetal aneuploidy detection by maternal plasma DNA sequencing. Obstet Gynecol. 2012;119:890-901.
6. Norton ME, Brar H, Weiss J, et al. Non-invasive chromosomal evaluation (NICE) study: results of a multicenter prospective cohort study for detection of fetal trisomy 21 and trisomy 18. Am J Obstet Gynecol. 2012;207: 137.e1-e8.
7. American College of Obstetricians and Gynecologists Committee on Genetics. Committee Opinion No. 545: Noninvasive prenatal testing for fetal aneuploidy. Obstet Gynecol. 2012;120:1532-1534.
8. American College of Obstetricians and Gynecologists Committee on Genetics. Committee Opinion No. 640: Cell-free DNA screening for fetal aneuploidy. Obstet Gynecol. 2015;126:e31-e37.
9. Wang Y, Zhu J, Chen Y, et al. Two cases of placental T21 mosaicism: challenging the detection limits of non-invasive prenatal testing. Prenat Diagn. 2013;33:1207-1210.
10. Choi H, Lau TK, Jiang FM, et al. Fetal aneuploidy screening by maternal plasma DNA sequencing: ‘false positive’ due to confined placental mosaicism. Prenat Diagn. 2013; 33:198-200.
11. Norton ME, Jelliffe-Pawlowski LL, Currier RJ. Chromosome abnormalities detected by current prenatal screening and noninvasive prenatal testing. Obstet Gynecol. 2014;124:979-986.
12. Agarwal A, Sayres LC, Cho MK, et al. Commercial landscape of noninvasive prenatal testing in the United States. Prenat Diagn. 2013;33:521-531.

ACKNOWLEDGEMENT
The PURLs Surveillance System was supported in part by Grant Number UL1RR024999 from the National Center For Research Resources, a Clinical Translational Science Award to the University of Chicago. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Center For Research Resources or the National Institutes of Health.

Copyright © 2016. The Family Physicians Inquiries Network. All rights reserved.

Reprinted with permission from the Family Physicians Inquiries Network and The Journal of Family Practice. 2016;65(1):49-52.

PRACTICE CHANGER
Discuss cell-free DNA testing when offering fetal aneuploidy screening to pregnant women.^1,2

Strength of recommendation
A: Based on multiple large, multicenter cohort studies.^1,2

A 28-year-old woman (gravida 2, para 1001) at 10 weeks’ gestation presents to your clinic for a routine first-trimester prenatal visit. Her first child has no known chromosomal abnormalities, and she has no family history of aneuploidy. She asks you which tests are available to screen her fetus for chromosomal abnormalities.

Pregnant women have traditionally been offered some combination of serum biomarkers and nuchal translucency to assess the risk for fetal aneuploidy. Cell-free DNA testing (cfDNA) is a form of noninvasive prenatal testing that uses maternal serum samples to conduct massively parallel sequencing of cell-free fetal DNA fragments.

It has been offered to pregnant women as a screening test to detect fetal chromosomal abnormalities since 2011, after multiple clinical studies found high sensitivities, specificities, and negative predictive values (NPVs) for detecting aneuploidy.^3-6 However, until 2015, practice guidelines from the American Congress of Obstetricians and Gynecologists (ACOG) recommended that standard aneuploidy screening or diagnostic testing be offered to all pregnant women and cfDNA be reserved for women with pregnancies at high risk for aneuploidy (strength of recommendation: B).⁷

CARE (Comparison of Aneuploidy Risk Evaluation) and NEXT (Noninvasive Examination of Trisomy) are two large studies that compared cfDNA and standard aneuploidy screening methods in pregnant women at low risk for fetal aneuploidy. Based on new data from these and other studies, ACOG and the Society for Maternal-Fetal Medicine (SMFM) released a new consensus statement in June 2015 that addressed the use of cfDNA in the general obstetric population. The two groups still recommend conventional first- and second-trimester screening by serum chemical biomarkers and nuchal translucency as the firstline approach for low-risk women who want to pursue aneuploidy screening; however, they also recommend that the risks and benefits of cfDNA be discussed with all patients.⁸

Continue for study summaries >>

STUDY SUMMARIES
CARE was a prospective, blinded, multicenter (21 US sites across 14 states) study that compared the aneuploidy detection rates of ­cfDNA to those of standard screening. Standard aneuploidy screening included assays of first- or second-trimester serum biomarkers with or without fetal nuchal translucency measurement.

This study enrolled 2,042 pregnant patients ages 18 to 49 (mean, 29.6) with singleton pregnancies. The population was racially and ethnically diverse (65% white, 22% black, 11% Hispanic, 7% Asian). This study included women with diabetes, thyroid disorders, and other comorbidities. cfDNA testing was done on 1,909 maternal blood samples for trisomy 21 and 1,905 for trisomy 18.

cfDNA and standard aneuploidy screening results were compared to pregnancy outcomes. The presence of aneuploidy was determined by physician-documented newborn physical exam (97%) or karyotype analysis (3%). In both live and nonlive births, the incidence of trisomy 21 was 5 of 1,909 cases (0.3%) and the incidence of trisomy 18 was 2 of 1,905 cases (0.1%).

The NPV of cfDNA in this study was 100% (95% confidence interval, 99.8%-100%) for both trisomy 21 and trisomy 18. The positive predictive value (PPV) was higher with cfDNA compared to standard screening (45.5% vs 4.2% for trisomy 21 and 40% vs 8.3% for trisomy 18). This means that approximately 1 in 25 women with a positive standard aneuploidy screen actually has aneuploidy. In contrast, nearly 1 in 2 women with a positive cfDNA result has aneuploidy.

Similarly, false-positive rates with cfDNA were significantly lower than those with standard screening. For trisomy 21, the cfDNA false-positive rate was 0.3% compared to 3.6% for standard screening (P < .001); for trisomy 18, the cfDNA false-positive rate was 0.2% compared to 0.6% for standard screening (P = .03).

NEXT was a prospective, blinded cohort study that compared cfDNA testing with standard first-trimester screening (with measurements of nuchal translucency and serum biochemical analysis) in a routine prenatal population at 35 centers in six countries.

This study enrolled 18,955 women ages 18 to 48 (mean, 31) who underwent traditional first-trimester screening and cfDNA testing. Eligible patients included pregnant women with a singleton pregnancy with a gestational age between 10 and 14.3 weeks. Prenatal screening results were compared to newborn outcomes using a documented newborn physical examination and, if performed, results of genetic testing. For women who had a miscarriage or stillbirth or chose to terminate the pregnancy, outcomes were determined by diagnostic genetic testing.

The primary outcome was the area under the receiver-operating-characteristic (ROC) curve for trisomy 21. Area under the ROC curve is a measure of a diagnostic test’s accuracy that plots sensitivity against 1 – specificity; < .700 is considered a poor test, whereas 1.00 is a perfect test. A secondary analysis evaluated cfDNA testing in low-risk women (ages < 35).

The area under the ROC curve was 0.999 for cfDNA compared with 0.958 for standard screening (P = .001). For diagnosis of trisomy 21, cfDNA had a higher PPV than standard testing (80.9% vs 3.4%; P < .001) and a lower false-positive rate (0.06% vs 5.4%; P < .001). These findings were consistent in the secondary analysis of low-risk women.

Both the CARE and NEXT trials also evaluated cfDNA testing versus standard screening for diagnosis of trisomy 13 and 18 and found higher PPVs and lower false-positive rates for cfDNA, compared with traditional screening.

WHAT’S NEW
Previously, cfDNA was recommended only for women with high-risk pregnancies. The new data demonstrate that cfDNA has substantially better PPVs and lower false-positive rates than standard fetal aneuploidy screening for the general obstetric population.

So while conventional screening tests remain the most appropriate methods for aneuploidy detection in the general obstetric population, according to ACOG and SMFM, the two groups now recommend that all screening options—including cfDNA—be discussed with every woman. Any woman may choose cfDNA but should be counseled about the risks and benefits.⁸

Continue for caveats >>

CAVEATS
Both the CARE and NEXT studies had limitations. They compared cfDNA testing with first- or second-trimester screening and did not evaluate integrated screening methods (sequential first- and second-trimester biomarkers plus first-trimester nuchal translucency), which have a slightly higher sensitivity and specificity than first-trimester screening alone.

Multiple companies offer cfDNA, and the test is not subject to FDA approval. The CARE and NEXT studies used tests from companies that provided funding for these studies and employ several of the study authors.

Although cfDNA has increased specificity compared to standard screening, there have been case reports of false-negative results. Further testing has shown that such false-negative results could be caused by mosaicism in either the fetus and/or placenta, vanishing twins, or maternal malig­nancies.^8-10

In the CARE and NEXT trials, cfDNA produced no results in 0.9% and 3% of women, respectively. Patients for whom cfDNA testing yields no results have higher rates of aneuploidy, and therefore require further diagnostic testing.

Because the prevalence of aneuploidy is lower in the general obstetric population than it is among women whose pregnancies are at high risk for aneuploidy, the PPV of cfDNA testing is also lower in the general obstetric population. This means that there are more false-positive results for women at lower risk for aneuploidy. Therefore, it is imperative that women with positive cfDNA tests receive follow-up diagnostic testing, such as chorionic villus sampling or amniocentesis, before making a decision about termination.

All commercially available cfDNA tests have high sensitivity and specificity for trisomy 21, 18, and 13. Some offer testing for sex chromosome abnormalities and microdeletions. However, current cfDNA testing methods are unable to detect up to 17% of other clinically significant chromosomal abnormalities,¹¹ and cfDNA cannot detect neural tube or ventral wall defects. Therefore, ACOG and SMFM recommend that women who choose cfDNA as their ­aneuploidy screening method also be offered maternal serum alpha-fetoprotein or ultrasound evaluation.

Continue for challenges to implementation >>

CHALLENGES TO IMPLEMENTATION
cfDNA testing is validated only for singleton pregnancies. Clinicians should obtain a baseline fetal ultrasound to confirm the number of fetuses, gestational age, and viability before ordering cfDNA to ensure it is the most appropriate screening test. This may add to the overall number of early pregnancy ultrasounds conducted.

Counseling patients about aneuploidy screening options is time-consuming and requires discussion of the limitations of each screening method and caution that a negative cfDNA result does not guarantee an unaffected fetus, nor does a positive result guarantee an affected fetus. However, aneuploidy screening is well within the scope of care for family practice clinicians who provide prenatal care, and referral to genetic specialists is not necessary or recommended.

Some patients may request cfDNA in order to facilitate earlier identification of fetal sex. In such cases, clinicians should advise patients that cfDNA testing also assesses trisomy risk. Patients who do not wish to assess their risk for aneuploidy should not receive cfDNA testing.

Finally, while cfDNA is routinely recommended for women with pregnancies considered at high risk for aneuploidy, many insurance companies do not cover the cost of cfDNA for women with low-risk pregnancies, and the test may cost up to $1,700.¹² The overall cost-effectiveness of cfDNA for aneuploidy screening in low-risk women is unknown.

References
1. Bianchi DW, Parker RL, Wentworth J, et al; CARE Study Group. DNA sequencing versus standard prenatal aneuploidy screening. N Engl J Med. 2014;370:799-808.
2. Norton ME, Jacobsson B, Swamy GK, et al. Cell-free DNA analysis for noninvasive examination of trisomy. N Engl J Med. 2015;372: 1589-1597.
3. Chiu RW, Akolekar R, Zheng YW, et al. Non-invasive prenatal assessment of trisomy 21 by multiplexed maternal plasma DNA sequencing: large scale validity study. BMJ. 2011; 342:c7401.
4. Ehrich M, Deciu C, Zwiefelhofer T, et al. Noninvasive detection of fetal trisomy 21 by sequencing of DNA in maternal blood: a study in a clinical setting. Am J Obstet Gynecol. 2011;204:205.e1-11.
5. Bianchi DW, Platt LD, Goldberg JD, et al; MatERNal BLood IS Source to Accurately diagnose fetal aneuploidy (MELISSA) Study Group. Genome-wide fetal aneuploidy detection by maternal plasma DNA sequencing. Obstet Gynecol. 2012;119:890-901.
6. Norton ME, Brar H, Weiss J, et al. Non-invasive chromosomal evaluation (NICE) study: results of a multicenter prospective cohort study for detection of fetal trisomy 21 and trisomy 18. Am J Obstet Gynecol. 2012;207: 137.e1-e8.
7. American College of Obstetricians and Gynecologists Committee on Genetics. Committee Opinion No. 545: Noninvasive prenatal testing for fetal aneuploidy. Obstet Gynecol. 2012;120:1532-1534.
8. American College of Obstetricians and Gynecologists Committee on Genetics. Committee Opinion No. 640: Cell-free DNA screening for fetal aneuploidy. Obstet Gynecol. 2015;126:e31-e37.
9. Wang Y, Zhu J, Chen Y, et al. Two cases of placental T21 mosaicism: challenging the detection limits of non-invasive prenatal testing. Prenat Diagn. 2013;33:1207-1210.
10. Choi H, Lau TK, Jiang FM, et al. Fetal aneuploidy screening by maternal plasma DNA sequencing: ‘false positive’ due to confined placental mosaicism. Prenat Diagn. 2013; 33:198-200.
11. Norton ME, Jelliffe-Pawlowski LL, Currier RJ. Chromosome abnormalities detected by current prenatal screening and noninvasive prenatal testing. Obstet Gynecol. 2014;124:979-986.
12. Agarwal A, Sayres LC, Cho MK, et al. Commercial landscape of noninvasive prenatal testing in the United States. Prenat Diagn. 2013;33:521-531.

ACKNOWLEDGEMENT
The PURLs Surveillance System was supported in part by Grant Number UL1RR024999 from the National Center For Research Resources, a Clinical Translational Science Award to the University of Chicago. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Center For Research Resources or the National Institutes of Health.

Copyright © 2016. The Family Physicians Inquiries Network. All rights reserved.

Reprinted with permission from the Family Physicians Inquiries Network and The Journal of Family Practice. 2016;65(1):49-52.

PRACTICE CHANGER
Discuss cell-free DNA testing when offering fetal aneuploidy screening to pregnant women.^1,2

Strength of recommendation
A: Based on multiple large, multicenter cohort studies.^1,2

A 28-year-old woman (gravida 2, para 1001) at 10 weeks’ gestation presents to your clinic for a routine first-trimester prenatal visit. Her first child has no known chromosomal abnormalities, and she has no family history of aneuploidy. She asks you which tests are available to screen her fetus for chromosomal abnormalities.

Pregnant women have traditionally been offered some combination of serum biomarkers and nuchal translucency to assess the risk for fetal aneuploidy. Cell-free DNA testing (cfDNA) is a form of noninvasive prenatal testing that uses maternal serum samples to conduct massively parallel sequencing of cell-free fetal DNA fragments.

It has been offered to pregnant women as a screening test to detect fetal chromosomal abnormalities since 2011, after multiple clinical studies found high sensitivities, specificities, and negative predictive values (NPVs) for detecting aneuploidy.^3-6 However, until 2015, practice guidelines from the American Congress of Obstetricians and Gynecologists (ACOG) recommended that standard aneuploidy screening or diagnostic testing be offered to all pregnant women and cfDNA be reserved for women with pregnancies at high risk for aneuploidy (strength of recommendation: B).⁷

CARE (Comparison of Aneuploidy Risk Evaluation) and NEXT (Noninvasive Examination of Trisomy) are two large studies that compared cfDNA and standard aneuploidy screening methods in pregnant women at low risk for fetal aneuploidy. Based on new data from these and other studies, ACOG and the Society for Maternal-Fetal Medicine (SMFM) released a new consensus statement in June 2015 that addressed the use of cfDNA in the general obstetric population. The two groups still recommend conventional first- and second-trimester screening by serum chemical biomarkers and nuchal translucency as the firstline approach for low-risk women who want to pursue aneuploidy screening; however, they also recommend that the risks and benefits of cfDNA be discussed with all patients.⁸

Continue for study summaries >>

STUDY SUMMARIES
CARE was a prospective, blinded, multicenter (21 US sites across 14 states) study that compared the aneuploidy detection rates of ­cfDNA to those of standard screening. Standard aneuploidy screening included assays of first- or second-trimester serum biomarkers with or without fetal nuchal translucency measurement.

This study enrolled 2,042 pregnant patients ages 18 to 49 (mean, 29.6) with singleton pregnancies. The population was racially and ethnically diverse (65% white, 22% black, 11% Hispanic, 7% Asian). This study included women with diabetes, thyroid disorders, and other comorbidities. cfDNA testing was done on 1,909 maternal blood samples for trisomy 21 and 1,905 for trisomy 18.

cfDNA and standard aneuploidy screening results were compared to pregnancy outcomes. The presence of aneuploidy was determined by physician-documented newborn physical exam (97%) or karyotype analysis (3%). In both live and nonlive births, the incidence of trisomy 21 was 5 of 1,909 cases (0.3%) and the incidence of trisomy 18 was 2 of 1,905 cases (0.1%).

The NPV of cfDNA in this study was 100% (95% confidence interval, 99.8%-100%) for both trisomy 21 and trisomy 18. The positive predictive value (PPV) was higher with cfDNA compared to standard screening (45.5% vs 4.2% for trisomy 21 and 40% vs 8.3% for trisomy 18). This means that approximately 1 in 25 women with a positive standard aneuploidy screen actually has aneuploidy. In contrast, nearly 1 in 2 women with a positive cfDNA result has aneuploidy.

Similarly, false-positive rates with cfDNA were significantly lower than those with standard screening. For trisomy 21, the cfDNA false-positive rate was 0.3% compared to 3.6% for standard screening (P < .001); for trisomy 18, the cfDNA false-positive rate was 0.2% compared to 0.6% for standard screening (P = .03).

NEXT was a prospective, blinded cohort study that compared cfDNA testing with standard first-trimester screening (with measurements of nuchal translucency and serum biochemical analysis) in a routine prenatal population at 35 centers in six countries.

This study enrolled 18,955 women ages 18 to 48 (mean, 31) who underwent traditional first-trimester screening and cfDNA testing. Eligible patients included pregnant women with a singleton pregnancy with a gestational age between 10 and 14.3 weeks. Prenatal screening results were compared to newborn outcomes using a documented newborn physical examination and, if performed, results of genetic testing. For women who had a miscarriage or stillbirth or chose to terminate the pregnancy, outcomes were determined by diagnostic genetic testing.

The primary outcome was the area under the receiver-operating-characteristic (ROC) curve for trisomy 21. Area under the ROC curve is a measure of a diagnostic test’s accuracy that plots sensitivity against 1 – specificity; < .700 is considered a poor test, whereas 1.00 is a perfect test. A secondary analysis evaluated cfDNA testing in low-risk women (ages < 35).

The area under the ROC curve was 0.999 for cfDNA compared with 0.958 for standard screening (P = .001). For diagnosis of trisomy 21, cfDNA had a higher PPV than standard testing (80.9% vs 3.4%; P < .001) and a lower false-positive rate (0.06% vs 5.4%; P < .001). These findings were consistent in the secondary analysis of low-risk women.

Both the CARE and NEXT trials also evaluated cfDNA testing versus standard screening for diagnosis of trisomy 13 and 18 and found higher PPVs and lower false-positive rates for cfDNA, compared with traditional screening.

WHAT’S NEW
Previously, cfDNA was recommended only for women with high-risk pregnancies. The new data demonstrate that cfDNA has substantially better PPVs and lower false-positive rates than standard fetal aneuploidy screening for the general obstetric population.

So while conventional screening tests remain the most appropriate methods for aneuploidy detection in the general obstetric population, according to ACOG and SMFM, the two groups now recommend that all screening options—including cfDNA—be discussed with every woman. Any woman may choose cfDNA but should be counseled about the risks and benefits.⁸

Continue for caveats >>

CAVEATS
Both the CARE and NEXT studies had limitations. They compared cfDNA testing with first- or second-trimester screening and did not evaluate integrated screening methods (sequential first- and second-trimester biomarkers plus first-trimester nuchal translucency), which have a slightly higher sensitivity and specificity than first-trimester screening alone.

Multiple companies offer cfDNA, and the test is not subject to FDA approval. The CARE and NEXT studies used tests from companies that provided funding for these studies and employ several of the study authors.

Although cfDNA has increased specificity compared to standard screening, there have been case reports of false-negative results. Further testing has shown that such false-negative results could be caused by mosaicism in either the fetus and/or placenta, vanishing twins, or maternal malig­nancies.^8-10

In the CARE and NEXT trials, cfDNA produced no results in 0.9% and 3% of women, respectively. Patients for whom cfDNA testing yields no results have higher rates of aneuploidy, and therefore require further diagnostic testing.

Because the prevalence of aneuploidy is lower in the general obstetric population than it is among women whose pregnancies are at high risk for aneuploidy, the PPV of cfDNA testing is also lower in the general obstetric population. This means that there are more false-positive results for women at lower risk for aneuploidy. Therefore, it is imperative that women with positive cfDNA tests receive follow-up diagnostic testing, such as chorionic villus sampling or amniocentesis, before making a decision about termination.

All commercially available cfDNA tests have high sensitivity and specificity for trisomy 21, 18, and 13. Some offer testing for sex chromosome abnormalities and microdeletions. However, current cfDNA testing methods are unable to detect up to 17% of other clinically significant chromosomal abnormalities,¹¹ and cfDNA cannot detect neural tube or ventral wall defects. Therefore, ACOG and SMFM recommend that women who choose cfDNA as their ­aneuploidy screening method also be offered maternal serum alpha-fetoprotein or ultrasound evaluation.

Continue for challenges to implementation >>

CHALLENGES TO IMPLEMENTATION
cfDNA testing is validated only for singleton pregnancies. Clinicians should obtain a baseline fetal ultrasound to confirm the number of fetuses, gestational age, and viability before ordering cfDNA to ensure it is the most appropriate screening test. This may add to the overall number of early pregnancy ultrasounds conducted.

Counseling patients about aneuploidy screening options is time-consuming and requires discussion of the limitations of each screening method and caution that a negative cfDNA result does not guarantee an unaffected fetus, nor does a positive result guarantee an affected fetus. However, aneuploidy screening is well within the scope of care for family practice clinicians who provide prenatal care, and referral to genetic specialists is not necessary or recommended.

Some patients may request cfDNA in order to facilitate earlier identification of fetal sex. In such cases, clinicians should advise patients that cfDNA testing also assesses trisomy risk. Patients who do not wish to assess their risk for aneuploidy should not receive cfDNA testing.

Finally, while cfDNA is routinely recommended for women with pregnancies considered at high risk for aneuploidy, many insurance companies do not cover the cost of cfDNA for women with low-risk pregnancies, and the test may cost up to $1,700.¹² The overall cost-effectiveness of cfDNA for aneuploidy screening in low-risk women is unknown.

References
1. Bianchi DW, Parker RL, Wentworth J, et al; CARE Study Group. DNA sequencing versus standard prenatal aneuploidy screening. N Engl J Med. 2014;370:799-808.
2. Norton ME, Jacobsson B, Swamy GK, et al. Cell-free DNA analysis for noninvasive examination of trisomy. N Engl J Med. 2015;372: 1589-1597.
3. Chiu RW, Akolekar R, Zheng YW, et al. Non-invasive prenatal assessment of trisomy 21 by multiplexed maternal plasma DNA sequencing: large scale validity study. BMJ. 2011; 342:c7401.
4. Ehrich M, Deciu C, Zwiefelhofer T, et al. Noninvasive detection of fetal trisomy 21 by sequencing of DNA in maternal blood: a study in a clinical setting. Am J Obstet Gynecol. 2011;204:205.e1-11.
5. Bianchi DW, Platt LD, Goldberg JD, et al; MatERNal BLood IS Source to Accurately diagnose fetal aneuploidy (MELISSA) Study Group. Genome-wide fetal aneuploidy detection by maternal plasma DNA sequencing. Obstet Gynecol. 2012;119:890-901.
6. Norton ME, Brar H, Weiss J, et al. Non-invasive chromosomal evaluation (NICE) study: results of a multicenter prospective cohort study for detection of fetal trisomy 21 and trisomy 18. Am J Obstet Gynecol. 2012;207: 137.e1-e8.
7. American College of Obstetricians and Gynecologists Committee on Genetics. Committee Opinion No. 545: Noninvasive prenatal testing for fetal aneuploidy. Obstet Gynecol. 2012;120:1532-1534.
8. American College of Obstetricians and Gynecologists Committee on Genetics. Committee Opinion No. 640: Cell-free DNA screening for fetal aneuploidy. Obstet Gynecol. 2015;126:e31-e37.
9. Wang Y, Zhu J, Chen Y, et al. Two cases of placental T21 mosaicism: challenging the detection limits of non-invasive prenatal testing. Prenat Diagn. 2013;33:1207-1210.
10. Choi H, Lau TK, Jiang FM, et al. Fetal aneuploidy screening by maternal plasma DNA sequencing: ‘false positive’ due to confined placental mosaicism. Prenat Diagn. 2013; 33:198-200.
11. Norton ME, Jelliffe-Pawlowski LL, Currier RJ. Chromosome abnormalities detected by current prenatal screening and noninvasive prenatal testing. Obstet Gynecol. 2014;124:979-986.
12. Agarwal A, Sayres LC, Cho MK, et al. Commercial landscape of noninvasive prenatal testing in the United States. Prenat Diagn. 2013;33:521-531.

ACKNOWLEDGEMENT
The PURLs Surveillance System was supported in part by Grant Number UL1RR024999 from the National Center For Research Resources, a Clinical Translational Science Award to the University of Chicago. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Center For Research Resources or the National Institutes of Health.

Copyright © 2016. The Family Physicians Inquiries Network. All rights reserved.

Reprinted with permission from the Family Physicians Inquiries Network and The Journal of Family Practice. 2016;65(1):49-52.

Illustrative case

A 28-year-old gravida 2, para 1001 at 10 weeks gestation presents to your clinic for a routine first-trimester prenatal visit. Her first child has no known chromosomal abnormalities and she has no family history of aneuploidy. She asks you which tests are available to screen her fetus for chromosomal abnormalities.

Pregnant women have traditionally been offered some combination of serum biomarkers and nuchal translucency to assess the risk of fetal aneuploidy. Cell-free DNA testing (cfDNA) is a form of noninvasive prenatal testing that uses maternal serum samples to conduct massively parallel sequencing of cell-free fetal DNA fragments. It has been offered to pregnant women as a screening test to detect fetal chromosomal abnormalities since 2011 after multiple clinical studies found high sensitivities, specificities, and negative predictive values (NPVs) for detecting aneuploidy.^3-6 However until 2015, practice guidelines from the American Congress of Obstetricians and Gynecologists (ACOG) recommended that standard aneuploidy screening or diagnostic testing be offered to all pregnant women and cfDNA be reserved for women with pregnancies at high risk for aneuploidy (strength of recommendation: B).⁷

CARE (Comparison of Aneuploidy Risk Evaluation) and NEXT (Noninvasive Examination of Trisomy) are 2 large studies that compared cfDNA and standard aneuploidy screening methods in pregnant women at low risk for fetal aneuploidy. Based on new data from these and other studies, ACOG and the Society for Maternal-Fetal Medicine (SMFM) released a new consensus statement in June 2015 that addressed the use of cfDNA in the general obstetric population. The 2 groups still recommend conventional first- and second-trimester screening by serum chemical biomarkers and nuchal translucency as the first-line approach for low-risk women who want to pursue aneuploidy screening; however, they also recommend that the risks and benefits of cfDNA should be discussed with all patients.⁸

STUDY SUMMARIES

CARE was a prospective, blinded, multicenter (21 US sites across 14 states) study that compared the aneuploidy detection rates of cfDNA to those of standard screening. Standard aneuploidy screening included assays of first- or second-trimester serum biomarkers with or without fetal nuchal translucency measurement.

This study enrolled 2042 pregnant patients ages 18 to 49 (mean: 29.6 years) with singleton pregnancies. The population was racially and ethnically diverse (65% white, 22% black, 11% Hispanic, 7% Asian). This study included women with diabetes mellitus, thyroid disorders, and other comorbidities. cfDNA testing was done on 1909 maternal blood samples for trisomy 21 and 1905 for trisomy 18.

cfDNA and standard aneuploidy screening results were compared to pregnancy outcomes. The presence of aneuploidy was determined by physician-documented newborn physical exam (97%) or karyotype analysis (3%). In both live and non-live births, the incidence of trisomy 21 was 5 of 1909 cases (0.3%) and the incidence of trisomy 18 was 2 of 1905 cases (0.1%).

The NPV of cfDNA in this study was 100% (95% confidence interval, 99.8%-100%) for both trisomy 21 and trisomy 18. The positive predictive value (PPV) was higher with cfDNA compared to standard screening (45.5% vs 4.2% for trisomy 21 and 40% vs 8.3% for trisomy 18). This means that approximately 1 in 25 women with a positive standard aneuploidy screen actually has aneuploidy. In contrast, nearly one in 2 women with a positive cfDNA result has aneuploidy.

Similarly, false positive rates with cfDNA were significantly lower than those with standard screening. For trisomy 21, the cfDNA false positive rate was 0.3% compared to 3.6% for standard screening (P<.001); for trisomy 18, the cfDNA false positive rate was 0.2% compared to 0.6% for standard screening (P=.03).

NEXT was a prospective, blinded cohort study that compared cfDNA testing with standard first-trimester screening (with measurements of nuchal translucency and serum biochemical analysis) in a routine prenatal population at 35 centers in 6 countries.

This study enrolled 18,955 women ages 18 to 48 (mean: 31 years) who underwent traditional first-trimester screening and cfDNA testing. Eligible patients included pregnant women with a singleton pregnancy with a gestational age between 10 and 14.3 weeks. Prenatal screening results were compared to newborn outcomes using a documented newborn physical examination and, if performed, results of genetic testing. For women who had a miscarriage or stillbirth or chose to terminate the pregnancy, outcomes were determined by diagnostic genetic testing.

The primary outcome was the area under the receiver-operating-characteristic (ROC) curve for trisomy 21. Area under the ROC curve is a measure of a diagnostic test’s accuracy that plots sensitivity against 1-specificity; <.700 is considered a poor test, whereas 1.00 is a perfect test. A secondary analysis evaluated cfDNA testing in low-risk women (ages <35 years).

cfDNA can't detect neural tube or ventral wall defects, so women who choose this method should be offered maternal serum alpha-fetoprotein or ultrasound evaluation.

The area under the ROC curve was 0.999 for cfDNA compared with 0.958 for standard screening (P=.001). For diagnosis of trisomy 21, cfDNA had a higher PPV than standard testing (80.9% vs 3.4%; P<.001) and a lower false positive rate (0.06% vs 5.4%; P<.001). These findings were consistent in the secondary analysis of low-risk women.

Both the CARE and NEXT trials also evaluated cfDNA testing vs standard screening for diagnosis of trisomy 13 and 18 and found higher PPVs and lower false positive rates for cfDNA compared with traditional screening.

WHAT'S NEW

Previously, cfDNA was recommended only for women with high-risk pregnancies. The new data demonstrate that cfDNA has substantially better PPVs and lower false positive rates than standard fetal aneuploidy screening for the general obstetrical population.

So while conventional screening tests remain the most appropriate methods for aneuploidy detection in the general obstetrical population, according to ACOG and SMFM, the 2 groups now recommend that all screening options—including cfDNA—be discussed with every woman. Any woman may choose cfDNA but should be counseled about the risks and benefits.⁸

CAVEATS

Both the CARE and NEXT studies had limitations. They compared cfDNA testing with first- or second-trimester screening and did not evaluate integrated screening methods (sequential first- and second-trimester biomarkers plus first-trimester nuchal translucency), which have a slightly higher sensitivity and specificity than first-trimester screening alone.

Multiple companies offer cfDNA, and the test is not subject to Food and Drug Administration approval. The CARE and NEXT studies used tests from companies that provided funding for these studies and employ several of the study authors.

Although cfDNA has increased specificity compared to standard screening, there have been case reports of false negative results. Further testing has shown that such false negative results could be caused by mosaicism in either the fetus and/or placenta, vanishing twins, or maternal malignancies.^8-10

In the CARE and NEXT trials, cfDNA produced no results in 0.9% and 3% of women, respectively. Patients for whom cfDNA testing yields no results have higher rates of aneuploidy, and therefore require further diagnostic testing.

Many insurance companies do not yet cover cfDNA for women with low-risk pregnancies, and the test may cost up to $1,700.

Because the prevalence of aneuploidy is lower in the general obstetric population than it is among women whose pregnancies are at high risk for aneuploidy, the PPV of cfDNA testing is also lower in the general obstetric population. This means that there are more false positive results for women at lower risk for aneuploidy. Therefore, it is imperative that women with positive cfDNA tests receive follow-up diagnostic testing such as chorionic villus sampling or amniocentesis before making a decision about termination.

All commercially available cfDNA tests have high sensitivity and specificity for trisomy 21, 18, and 13. Some offer testing for sex chromosome abnormalities and microdeletions. However, current cfDNA testing methods are unable to detect up to 17% of other clinically significant chromosomal abnormalities,¹¹ and cfDNA cannot detect neural tube or ventral wall defects. Therefore, ACOG and SMFM recommend that women who choose cfDNA as their aneuploidy screening method should also be offered maternal serum alpha-fetoprotein or ultrasound evaluation.

CHALLENGES TO IMPLEMENTATION

cfDNA testing is validated only for singleton pregnancies. Physicians should obtain a baseline fetal ultrasound to confirm the number of fetuses, gestational age, and viability before ordering cfDNA to ensure it is the most appropriate screening test. This may add to the overall number of early pregnancy ultrasounds conducted.

Counseling patients about aneuploidy screening options is time-consuming, and requires discussion of the limitations of each screening method and caution that a negative cfDNA result does not guarantee an unaffected fetus, nor does a positive result guarantee an affected fetus. However, aneuploidy screening is well within the scope of care for family physicians who provide prenatal care, and referral to genetic specialists is not necessary or recommended.

Some patients may request cfDNA in order to facilitate earlier identification of fetal sex. In such cases, physicians should advise patients that cfDNA testing also assesses trisomy risk. Patients who do not wish to assess their risk for aneuploidy should not receive cfDNA testing.

Finally, while cfDNA is routinely recommended for women with pregnancies considered at high risk for aneuploidy, many insurance companies do not cover the cost of cfDNA for women with low-risk pregnancies, and the test may cost up to $1,700.¹² The overall cost-effectiveness of cfDNA for aneuploidy screening in low-risk women is unknown.

ACKNOWLEDGEMENT 
The PURLs Surveillance System was supported in part by Grant Number UL1RR024999 from the National Center For Research Resources, a Clinical Translational Science Award to the University of Chicago. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Center For Research Resources or the National Institutes of Health.

Illustrative case

A 28-year-old gravida 2, para 1001 at 10 weeks gestation presents to your clinic for a routine first-trimester prenatal visit. Her first child has no known chromosomal abnormalities and she has no family history of aneuploidy. She asks you which tests are available to screen her fetus for chromosomal abnormalities.

Pregnant women have traditionally been offered some combination of serum biomarkers and nuchal translucency to assess the risk of fetal aneuploidy. Cell-free DNA testing (cfDNA) is a form of noninvasive prenatal testing that uses maternal serum samples to conduct massively parallel sequencing of cell-free fetal DNA fragments. It has been offered to pregnant women as a screening test to detect fetal chromosomal abnormalities since 2011 after multiple clinical studies found high sensitivities, specificities, and negative predictive values (NPVs) for detecting aneuploidy.^3-6 However until 2015, practice guidelines from the American Congress of Obstetricians and Gynecologists (ACOG) recommended that standard aneuploidy screening or diagnostic testing be offered to all pregnant women and cfDNA be reserved for women with pregnancies at high risk for aneuploidy (strength of recommendation: B).⁷

CARE (Comparison of Aneuploidy Risk Evaluation) and NEXT (Noninvasive Examination of Trisomy) are 2 large studies that compared cfDNA and standard aneuploidy screening methods in pregnant women at low risk for fetal aneuploidy. Based on new data from these and other studies, ACOG and the Society for Maternal-Fetal Medicine (SMFM) released a new consensus statement in June 2015 that addressed the use of cfDNA in the general obstetric population. The 2 groups still recommend conventional first- and second-trimester screening by serum chemical biomarkers and nuchal translucency as the first-line approach for low-risk women who want to pursue aneuploidy screening; however, they also recommend that the risks and benefits of cfDNA should be discussed with all patients.⁸

STUDY SUMMARIES

CARE was a prospective, blinded, multicenter (21 US sites across 14 states) study that compared the aneuploidy detection rates of cfDNA to those of standard screening. Standard aneuploidy screening included assays of first- or second-trimester serum biomarkers with or without fetal nuchal translucency measurement.

This study enrolled 2042 pregnant patients ages 18 to 49 (mean: 29.6 years) with singleton pregnancies. The population was racially and ethnically diverse (65% white, 22% black, 11% Hispanic, 7% Asian). This study included women with diabetes mellitus, thyroid disorders, and other comorbidities. cfDNA testing was done on 1909 maternal blood samples for trisomy 21 and 1905 for trisomy 18.

cfDNA and standard aneuploidy screening results were compared to pregnancy outcomes. The presence of aneuploidy was determined by physician-documented newborn physical exam (97%) or karyotype analysis (3%). In both live and non-live births, the incidence of trisomy 21 was 5 of 1909 cases (0.3%) and the incidence of trisomy 18 was 2 of 1905 cases (0.1%).

The NPV of cfDNA in this study was 100% (95% confidence interval, 99.8%-100%) for both trisomy 21 and trisomy 18. The positive predictive value (PPV) was higher with cfDNA compared to standard screening (45.5% vs 4.2% for trisomy 21 and 40% vs 8.3% for trisomy 18). This means that approximately 1 in 25 women with a positive standard aneuploidy screen actually has aneuploidy. In contrast, nearly one in 2 women with a positive cfDNA result has aneuploidy.

Similarly, false positive rates with cfDNA were significantly lower than those with standard screening. For trisomy 21, the cfDNA false positive rate was 0.3% compared to 3.6% for standard screening (P<.001); for trisomy 18, the cfDNA false positive rate was 0.2% compared to 0.6% for standard screening (P=.03).

NEXT was a prospective, blinded cohort study that compared cfDNA testing with standard first-trimester screening (with measurements of nuchal translucency and serum biochemical analysis) in a routine prenatal population at 35 centers in 6 countries.

This study enrolled 18,955 women ages 18 to 48 (mean: 31 years) who underwent traditional first-trimester screening and cfDNA testing. Eligible patients included pregnant women with a singleton pregnancy with a gestational age between 10 and 14.3 weeks. Prenatal screening results were compared to newborn outcomes using a documented newborn physical examination and, if performed, results of genetic testing. For women who had a miscarriage or stillbirth or chose to terminate the pregnancy, outcomes were determined by diagnostic genetic testing.

The primary outcome was the area under the receiver-operating-characteristic (ROC) curve for trisomy 21. Area under the ROC curve is a measure of a diagnostic test’s accuracy that plots sensitivity against 1-specificity; <.700 is considered a poor test, whereas 1.00 is a perfect test. A secondary analysis evaluated cfDNA testing in low-risk women (ages <35 years).

cfDNA can't detect neural tube or ventral wall defects, so women who choose this method should be offered maternal serum alpha-fetoprotein or ultrasound evaluation.

The area under the ROC curve was 0.999 for cfDNA compared with 0.958 for standard screening (P=.001). For diagnosis of trisomy 21, cfDNA had a higher PPV than standard testing (80.9% vs 3.4%; P<.001) and a lower false positive rate (0.06% vs 5.4%; P<.001). These findings were consistent in the secondary analysis of low-risk women.

Both the CARE and NEXT trials also evaluated cfDNA testing vs standard screening for diagnosis of trisomy 13 and 18 and found higher PPVs and lower false positive rates for cfDNA compared with traditional screening.

WHAT'S NEW

Previously, cfDNA was recommended only for women with high-risk pregnancies. The new data demonstrate that cfDNA has substantially better PPVs and lower false positive rates than standard fetal aneuploidy screening for the general obstetrical population.

So while conventional screening tests remain the most appropriate methods for aneuploidy detection in the general obstetrical population, according to ACOG and SMFM, the 2 groups now recommend that all screening options—including cfDNA—be discussed with every woman. Any woman may choose cfDNA but should be counseled about the risks and benefits.⁸

CAVEATS

Both the CARE and NEXT studies had limitations. They compared cfDNA testing with first- or second-trimester screening and did not evaluate integrated screening methods (sequential first- and second-trimester biomarkers plus first-trimester nuchal translucency), which have a slightly higher sensitivity and specificity than first-trimester screening alone.

Multiple companies offer cfDNA, and the test is not subject to Food and Drug Administration approval. The CARE and NEXT studies used tests from companies that provided funding for these studies and employ several of the study authors.

Although cfDNA has increased specificity compared to standard screening, there have been case reports of false negative results. Further testing has shown that such false negative results could be caused by mosaicism in either the fetus and/or placenta, vanishing twins, or maternal malignancies.^8-10

In the CARE and NEXT trials, cfDNA produced no results in 0.9% and 3% of women, respectively. Patients for whom cfDNA testing yields no results have higher rates of aneuploidy, and therefore require further diagnostic testing.

Many insurance companies do not yet cover cfDNA for women with low-risk pregnancies, and the test may cost up to $1,700.

Because the prevalence of aneuploidy is lower in the general obstetric population than it is among women whose pregnancies are at high risk for aneuploidy, the PPV of cfDNA testing is also lower in the general obstetric population. This means that there are more false positive results for women at lower risk for aneuploidy. Therefore, it is imperative that women with positive cfDNA tests receive follow-up diagnostic testing such as chorionic villus sampling or amniocentesis before making a decision about termination.

All commercially available cfDNA tests have high sensitivity and specificity for trisomy 21, 18, and 13. Some offer testing for sex chromosome abnormalities and microdeletions. However, current cfDNA testing methods are unable to detect up to 17% of other clinically significant chromosomal abnormalities,¹¹ and cfDNA cannot detect neural tube or ventral wall defects. Therefore, ACOG and SMFM recommend that women who choose cfDNA as their aneuploidy screening method should also be offered maternal serum alpha-fetoprotein or ultrasound evaluation.

CHALLENGES TO IMPLEMENTATION

cfDNA testing is validated only for singleton pregnancies. Physicians should obtain a baseline fetal ultrasound to confirm the number of fetuses, gestational age, and viability before ordering cfDNA to ensure it is the most appropriate screening test. This may add to the overall number of early pregnancy ultrasounds conducted.

Counseling patients about aneuploidy screening options is time-consuming, and requires discussion of the limitations of each screening method and caution that a negative cfDNA result does not guarantee an unaffected fetus, nor does a positive result guarantee an affected fetus. However, aneuploidy screening is well within the scope of care for family physicians who provide prenatal care, and referral to genetic specialists is not necessary or recommended.

Some patients may request cfDNA in order to facilitate earlier identification of fetal sex. In such cases, physicians should advise patients that cfDNA testing also assesses trisomy risk. Patients who do not wish to assess their risk for aneuploidy should not receive cfDNA testing.

Finally, while cfDNA is routinely recommended for women with pregnancies considered at high risk for aneuploidy, many insurance companies do not cover the cost of cfDNA for women with low-risk pregnancies, and the test may cost up to $1,700.¹² The overall cost-effectiveness of cfDNA for aneuploidy screening in low-risk women is unknown.

ACKNOWLEDGEMENT 
The PURLs Surveillance System was supported in part by Grant Number UL1RR024999 from the National Center For Research Resources, a Clinical Translational Science Award to the University of Chicago. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Center For Research Resources or the National Institutes of Health.

Illustrative case

A 28-year-old gravida 2, para 1001 at 10 weeks gestation presents to your clinic for a routine first-trimester prenatal visit. Her first child has no known chromosomal abnormalities and she has no family history of aneuploidy. She asks you which tests are available to screen her fetus for chromosomal abnormalities.

Pregnant women have traditionally been offered some combination of serum biomarkers and nuchal translucency to assess the risk of fetal aneuploidy. Cell-free DNA testing (cfDNA) is a form of noninvasive prenatal testing that uses maternal serum samples to conduct massively parallel sequencing of cell-free fetal DNA fragments. It has been offered to pregnant women as a screening test to detect fetal chromosomal abnormalities since 2011 after multiple clinical studies found high sensitivities, specificities, and negative predictive values (NPVs) for detecting aneuploidy.^3-6 However until 2015, practice guidelines from the American Congress of Obstetricians and Gynecologists (ACOG) recommended that standard aneuploidy screening or diagnostic testing be offered to all pregnant women and cfDNA be reserved for women with pregnancies at high risk for aneuploidy (strength of recommendation: B).⁷

CARE (Comparison of Aneuploidy Risk Evaluation) and NEXT (Noninvasive Examination of Trisomy) are 2 large studies that compared cfDNA and standard aneuploidy screening methods in pregnant women at low risk for fetal aneuploidy. Based on new data from these and other studies, ACOG and the Society for Maternal-Fetal Medicine (SMFM) released a new consensus statement in June 2015 that addressed the use of cfDNA in the general obstetric population. The 2 groups still recommend conventional first- and second-trimester screening by serum chemical biomarkers and nuchal translucency as the first-line approach for low-risk women who want to pursue aneuploidy screening; however, they also recommend that the risks and benefits of cfDNA should be discussed with all patients.⁸

STUDY SUMMARIES

CARE was a prospective, blinded, multicenter (21 US sites across 14 states) study that compared the aneuploidy detection rates of cfDNA to those of standard screening. Standard aneuploidy screening included assays of first- or second-trimester serum biomarkers with or without fetal nuchal translucency measurement.

This study enrolled 2042 pregnant patients ages 18 to 49 (mean: 29.6 years) with singleton pregnancies. The population was racially and ethnically diverse (65% white, 22% black, 11% Hispanic, 7% Asian). This study included women with diabetes mellitus, thyroid disorders, and other comorbidities. cfDNA testing was done on 1909 maternal blood samples for trisomy 21 and 1905 for trisomy 18.

cfDNA and standard aneuploidy screening results were compared to pregnancy outcomes. The presence of aneuploidy was determined by physician-documented newborn physical exam (97%) or karyotype analysis (3%). In both live and non-live births, the incidence of trisomy 21 was 5 of 1909 cases (0.3%) and the incidence of trisomy 18 was 2 of 1905 cases (0.1%).

The NPV of cfDNA in this study was 100% (95% confidence interval, 99.8%-100%) for both trisomy 21 and trisomy 18. The positive predictive value (PPV) was higher with cfDNA compared to standard screening (45.5% vs 4.2% for trisomy 21 and 40% vs 8.3% for trisomy 18). This means that approximately 1 in 25 women with a positive standard aneuploidy screen actually has aneuploidy. In contrast, nearly one in 2 women with a positive cfDNA result has aneuploidy.

Similarly, false positive rates with cfDNA were significantly lower than those with standard screening. For trisomy 21, the cfDNA false positive rate was 0.3% compared to 3.6% for standard screening (P<.001); for trisomy 18, the cfDNA false positive rate was 0.2% compared to 0.6% for standard screening (P=.03).

NEXT was a prospective, blinded cohort study that compared cfDNA testing with standard first-trimester screening (with measurements of nuchal translucency and serum biochemical analysis) in a routine prenatal population at 35 centers in 6 countries.

This study enrolled 18,955 women ages 18 to 48 (mean: 31 years) who underwent traditional first-trimester screening and cfDNA testing. Eligible patients included pregnant women with a singleton pregnancy with a gestational age between 10 and 14.3 weeks. Prenatal screening results were compared to newborn outcomes using a documented newborn physical examination and, if performed, results of genetic testing. For women who had a miscarriage or stillbirth or chose to terminate the pregnancy, outcomes were determined by diagnostic genetic testing.

The primary outcome was the area under the receiver-operating-characteristic (ROC) curve for trisomy 21. Area under the ROC curve is a measure of a diagnostic test’s accuracy that plots sensitivity against 1-specificity; <.700 is considered a poor test, whereas 1.00 is a perfect test. A secondary analysis evaluated cfDNA testing in low-risk women (ages <35 years).

cfDNA can't detect neural tube or ventral wall defects, so women who choose this method should be offered maternal serum alpha-fetoprotein or ultrasound evaluation.

The area under the ROC curve was 0.999 for cfDNA compared with 0.958 for standard screening (P=.001). For diagnosis of trisomy 21, cfDNA had a higher PPV than standard testing (80.9% vs 3.4%; P<.001) and a lower false positive rate (0.06% vs 5.4%; P<.001). These findings were consistent in the secondary analysis of low-risk women.

Both the CARE and NEXT trials also evaluated cfDNA testing vs standard screening for diagnosis of trisomy 13 and 18 and found higher PPVs and lower false positive rates for cfDNA compared with traditional screening.

WHAT'S NEW

Previously, cfDNA was recommended only for women with high-risk pregnancies. The new data demonstrate that cfDNA has substantially better PPVs and lower false positive rates than standard fetal aneuploidy screening for the general obstetrical population.

So while conventional screening tests remain the most appropriate methods for aneuploidy detection in the general obstetrical population, according to ACOG and SMFM, the 2 groups now recommend that all screening options—including cfDNA—be discussed with every woman. Any woman may choose cfDNA but should be counseled about the risks and benefits.⁸

CAVEATS

Both the CARE and NEXT studies had limitations. They compared cfDNA testing with first- or second-trimester screening and did not evaluate integrated screening methods (sequential first- and second-trimester biomarkers plus first-trimester nuchal translucency), which have a slightly higher sensitivity and specificity than first-trimester screening alone.

Multiple companies offer cfDNA, and the test is not subject to Food and Drug Administration approval. The CARE and NEXT studies used tests from companies that provided funding for these studies and employ several of the study authors.

Although cfDNA has increased specificity compared to standard screening, there have been case reports of false negative results. Further testing has shown that such false negative results could be caused by mosaicism in either the fetus and/or placenta, vanishing twins, or maternal malignancies.^8-10

In the CARE and NEXT trials, cfDNA produced no results in 0.9% and 3% of women, respectively. Patients for whom cfDNA testing yields no results have higher rates of aneuploidy, and therefore require further diagnostic testing.

Many insurance companies do not yet cover cfDNA for women with low-risk pregnancies, and the test may cost up to $1,700.

Because the prevalence of aneuploidy is lower in the general obstetric population than it is among women whose pregnancies are at high risk for aneuploidy, the PPV of cfDNA testing is also lower in the general obstetric population. This means that there are more false positive results for women at lower risk for aneuploidy. Therefore, it is imperative that women with positive cfDNA tests receive follow-up diagnostic testing such as chorionic villus sampling or amniocentesis before making a decision about termination.

All commercially available cfDNA tests have high sensitivity and specificity for trisomy 21, 18, and 13. Some offer testing for sex chromosome abnormalities and microdeletions. However, current cfDNA testing methods are unable to detect up to 17% of other clinically significant chromosomal abnormalities,¹¹ and cfDNA cannot detect neural tube or ventral wall defects. Therefore, ACOG and SMFM recommend that women who choose cfDNA as their aneuploidy screening method should also be offered maternal serum alpha-fetoprotein or ultrasound evaluation.

CHALLENGES TO IMPLEMENTATION

cfDNA testing is validated only for singleton pregnancies. Physicians should obtain a baseline fetal ultrasound to confirm the number of fetuses, gestational age, and viability before ordering cfDNA to ensure it is the most appropriate screening test. This may add to the overall number of early pregnancy ultrasounds conducted.

Counseling patients about aneuploidy screening options is time-consuming, and requires discussion of the limitations of each screening method and caution that a negative cfDNA result does not guarantee an unaffected fetus, nor does a positive result guarantee an affected fetus. However, aneuploidy screening is well within the scope of care for family physicians who provide prenatal care, and referral to genetic specialists is not necessary or recommended.

Some patients may request cfDNA in order to facilitate earlier identification of fetal sex. In such cases, physicians should advise patients that cfDNA testing also assesses trisomy risk. Patients who do not wish to assess their risk for aneuploidy should not receive cfDNA testing.

Finally, while cfDNA is routinely recommended for women with pregnancies considered at high risk for aneuploidy, many insurance companies do not cover the cost of cfDNA for women with low-risk pregnancies, and the test may cost up to $1,700.¹² The overall cost-effectiveness of cfDNA for aneuploidy screening in low-risk women is unknown.

ACKNOWLEDGEMENT 
The PURLs Surveillance System was supported in part by Grant Number UL1RR024999 from the National Center For Research Resources, a Clinical Translational Science Award to the University of Chicago. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Center For Research Resources or the National Institutes of Health.

PRACTICE CHANGER
Consider using nonsterile gloves during minor skin excisions (even those requiring sutures), because the infection rate is not increased compared to using sterile gloves.¹

STRENGTH OF RECOMMENDATION
B: Based on a randomized controlled trial (RCT) conducted in a primary care practice.¹

ILLUSTRATIVE CASE
A 50-year-old man comes to your office to have a mole removed from his arm. You decide to excise the lesion in your office today. Do you need to use sterile gloves for this procedure, or can you use gloves from the clean nonsterile box in the exam room?

Nonsterile gloves are readily available during a typical office visit and cost up to a dollar less per pair than sterile gloves.^1-3 Studies conducted in settings other than primary care offices have shown that nonsterile gloves do not increase the risk for infection during several types of minor skin procedures.

A partially blinded RCT in an emergency department found no significant difference in infection rates between the use of sterile (6.1%) and nonsterile (4.4%) gloves during laceration repairs.² Similarly, a small RCT in an outpatient dermatology clinic and a larger prospective trial by a Mohs dermatologist showed that infection rates were not increased after Mohs surgery using nonsterile (0.49%) versus sterile (0.50%) gloves.^3,4

Guidelines on the use of sterile versus nonsterile gloves for minor skin excisions in outpatient primary care are difficult to come by. Current guidelines from the CDC and other agencies regarding surgical site infections are broad and focus on the operating room environment.^5-7

The American Academy of Dermatology is working on a guideline for treatment of nonmelanoma skin cancer, due out this winter, which may provide additional guidance.⁸ A 2003 review instructed primary care providers to use sterile gloves for excisional skin biopsies that require sutures.⁹

The 2015 study by Heal et al¹ appears to be the first RCT to address the question of sterile versus nonsterile glove use for minor skin excisions in a primary care outpatient practice.

Continue for study summary >>

STUDY SUMMARY 
Nonsterile is not inferior
Heal et al¹ conducted a prospective, noninferiority RCT to compare the incidence of infection after minor skin surgery performed by six physicians from a single general practice in Australia using sterile versus nonsterile clean gloves. They evaluated 576 consecutive patients who presented for skin excision between June 2012 and March 2013. Eighty-three patients were excluded because they had a latex allergy, were using oral antibiotics or immunosuppressive drugs, or required a skin flap procedure or excision of a sebaceous cyst. The physicians followed a standard process for performing the procedures and did not use topical antibiotics or antiseptic cleansing after the procedure.

The primary outcome was surgical site infection within 30 days of the excision, defined as purulent discharge; pain or tenderness; localized swelling, redness, or heat at the site; or a diagnosis of skin or soft-tissue infection by a general practitioner. The clinicians who assessed for infection were blinded to the patient’s assignment to the sterile or nonsterile glove group, and a stitch abscess was not counted as an infection.

The patients’ mean age was 65, and 59% were men. At baseline, there were no large differences between patients in the sterile and nonsterile glove groups in terms of smoking status, anticoagulant or corticosteroid use, diabetes, excision site, size of excision, and median days until removal of sutures. The lesions were identified histologically as nevus or seborrheic keratosis; skin cancer and precursor; or other.

The incidence of infection in the nonsterile gloves group was 21/241 (8.7%) versus 22/237 in the control group (9.3%). The confidence interval (CI; 95%) for the difference in infection rate (–0.6%) was –4.0% to 2.9%—significantly below the predetermined noninferiority margin of 7%. In a sensitivity analysis of patients lost to follow-up (15 patients, 3%) that assumed all of these patients were without infection, or with infection, the CI was still below the noninferiority margin of 7%. The per-protocol analysis showed similar results.

Continue for what's new >>

WHAT’S NEW 
New evidence questions the need for sterile gloves for in-office excisions
Heal et al¹ demonstrated that in a primary care setting, nonsterile gloves are not inferior to sterile gloves for excisional procedures that require sutures. While standard practice has many family practice providers using sterile gloves for these procedures, this study promotes changing this ­behavior.

Continue for caveats >>

CAVEATS 
High infection rate, other factors may limit generalizability
The overall rate of infection in this study (9%) was higher than that found in the studies from emergency medicine and dermatology literature cited earlier.^2-4 A similarly high infection rate has been found in other studies of minor surgery by Heal et al, including a 2006 study that showed a wound infection rate of 8.6%.¹⁰ The significance of the higher infection rate is unknown, but there is no clear reason why nonsterile gloves might be less effective in preventing infection in environments with lower infection rates.

This was not a double-blinded study, and clinicians might change their behavior during a procedure depending on the type of gloves they are wearing. The sterile gloves used in this study contained powder, while the nonsterile gloves were powderless, but this variable is not known to affect infection rates. A study of Mohs surgery avoided this variable by only using powderless gloves; outcomes were similar in terms of the difference in infection rate between sterile and nonsterile gloves.⁴

Continue for challenges to implementation >>

CHALLENGES TO IMPLEMENTATION 
Ingrained habits can be hard to change
Tradition and training die hard. While multiple studies in several settings have found nonsterile gloves to be noninferior to sterile gloves in preventing surgical site infection after minor skin surgeries, this single study in the primary care office setting may not be enough to sway clinicians from ingrained habits.

REFERENCES 
1. Heal C, Sriharan S, Buttner PG, et al. Comparing non-sterile to sterile gloves for minor surgery: a prospective randomized controlled non-inferiority trial. Med J Aust. 2015;202:27-31.
2. Perelman VS, Francis GJ, Rutledge T, et al. Sterile versus nonsterile gloves for repair of uncomplicated lacerations in the emergency department: a randomized controlled trial. Ann Emerg Med. 2004;43:362-370.
3. Mehta D, Chambers N, Adams B, et al. Comparison of the prevalence of surgical site infection with use of sterile versus nonsterile gloves for resection and reconstruction during Mohs surgery. Dermatol Surg. 2014;40: 234-239.
4. Xia Y, Cho S, Greenway HT, et al. Infection rates of wound repairs during Mohs micrographic surgery using sterile versus nonsterile gloves: a prospective randomized pilot study. Dermatol Surg. 2011;37:651-656.
5. Mangram AJ, Horan TC, Pearson ML, et al. Guideline for prevention of surgical site infection, 1999. Centers for Disease Control and Prevention (CDC) Hospital Infection Control Practices Advisory Committee. Am J Infect Control. 1999;27:97-132.
6. National Institute for Health and Care Excellence. Surgical site infection: prevention and treatment of surgical site infection. www.nice.org.uk/guidance/cg74/chapter/1-recommendations. Accessed November 17, 2015.
7. National Health and Medical Research Council. Australian Guidelines for the Prevention and Control of Infection in Healthcare (2010). www.nhmrc.gov.au/book/html-australian-guideline-sprevention-and-control-infection-healthcare-2010. Accessed November 17, 2015.
8. American Academy of Dermatology. Clinical guidelines. www.aad.org/education/clinical-guidelines. Accessed November 17, 2015.
9. Zuber TJ. Fusiform excision. Am Fam Physician. 2003;67:1539-1544.
10. Heal C, Buettner P, Browning S. Risk factors for wound infection after minor surgery in general practice. Med J Aust. 2006;18:255-258.

ACKNOWLEDGEMENT
The PURLs Surveillance System was supported in part by Grant Number UL1RR024999 from the National Center For Research Resources, a Clinical Translational Science Award to the University of Chicago. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Center For Research Resources or the National Institutes of Health.

Copyright © 2015. The Family Physicians Inquiries Network. All rights reserved.

Reprinted with permission from the Family Physicians Inquiries Network and The Journal of Family Practice. 2015;64(11):723-724, 727. 

PRACTICE CHANGER
Consider using nonsterile gloves during minor skin excisions (even those requiring sutures), because the infection rate is not increased compared to using sterile gloves.¹

STRENGTH OF RECOMMENDATION
B: Based on a randomized controlled trial (RCT) conducted in a primary care practice.¹

ILLUSTRATIVE CASE
A 50-year-old man comes to your office to have a mole removed from his arm. You decide to excise the lesion in your office today. Do you need to use sterile gloves for this procedure, or can you use gloves from the clean nonsterile box in the exam room?

Nonsterile gloves are readily available during a typical office visit and cost up to a dollar less per pair than sterile gloves.^1-3 Studies conducted in settings other than primary care offices have shown that nonsterile gloves do not increase the risk for infection during several types of minor skin procedures.

A partially blinded RCT in an emergency department found no significant difference in infection rates between the use of sterile (6.1%) and nonsterile (4.4%) gloves during laceration repairs.² Similarly, a small RCT in an outpatient dermatology clinic and a larger prospective trial by a Mohs dermatologist showed that infection rates were not increased after Mohs surgery using nonsterile (0.49%) versus sterile (0.50%) gloves.^3,4

Guidelines on the use of sterile versus nonsterile gloves for minor skin excisions in outpatient primary care are difficult to come by. Current guidelines from the CDC and other agencies regarding surgical site infections are broad and focus on the operating room environment.^5-7

The American Academy of Dermatology is working on a guideline for treatment of nonmelanoma skin cancer, due out this winter, which may provide additional guidance.⁸ A 2003 review instructed primary care providers to use sterile gloves for excisional skin biopsies that require sutures.⁹

The 2015 study by Heal et al¹ appears to be the first RCT to address the question of sterile versus nonsterile glove use for minor skin excisions in a primary care outpatient practice.

Continue for study summary >>

STUDY SUMMARY 
Nonsterile is not inferior
Heal et al¹ conducted a prospective, noninferiority RCT to compare the incidence of infection after minor skin surgery performed by six physicians from a single general practice in Australia using sterile versus nonsterile clean gloves. They evaluated 576 consecutive patients who presented for skin excision between June 2012 and March 2013. Eighty-three patients were excluded because they had a latex allergy, were using oral antibiotics or immunosuppressive drugs, or required a skin flap procedure or excision of a sebaceous cyst. The physicians followed a standard process for performing the procedures and did not use topical antibiotics or antiseptic cleansing after the procedure.

The primary outcome was surgical site infection within 30 days of the excision, defined as purulent discharge; pain or tenderness; localized swelling, redness, or heat at the site; or a diagnosis of skin or soft-tissue infection by a general practitioner. The clinicians who assessed for infection were blinded to the patient’s assignment to the sterile or nonsterile glove group, and a stitch abscess was not counted as an infection.

The patients’ mean age was 65, and 59% were men. At baseline, there were no large differences between patients in the sterile and nonsterile glove groups in terms of smoking status, anticoagulant or corticosteroid use, diabetes, excision site, size of excision, and median days until removal of sutures. The lesions were identified histologically as nevus or seborrheic keratosis; skin cancer and precursor; or other.

The incidence of infection in the nonsterile gloves group was 21/241 (8.7%) versus 22/237 in the control group (9.3%). The confidence interval (CI; 95%) for the difference in infection rate (–0.6%) was –4.0% to 2.9%—significantly below the predetermined noninferiority margin of 7%. In a sensitivity analysis of patients lost to follow-up (15 patients, 3%) that assumed all of these patients were without infection, or with infection, the CI was still below the noninferiority margin of 7%. The per-protocol analysis showed similar results.

Continue for what's new >>

WHAT’S NEW 
New evidence questions the need for sterile gloves for in-office excisions
Heal et al¹ demonstrated that in a primary care setting, nonsterile gloves are not inferior to sterile gloves for excisional procedures that require sutures. While standard practice has many family practice providers using sterile gloves for these procedures, this study promotes changing this ­behavior.

Continue for caveats >>

CAVEATS 
High infection rate, other factors may limit generalizability
The overall rate of infection in this study (9%) was higher than that found in the studies from emergency medicine and dermatology literature cited earlier.^2-4 A similarly high infection rate has been found in other studies of minor surgery by Heal et al, including a 2006 study that showed a wound infection rate of 8.6%.¹⁰ The significance of the higher infection rate is unknown, but there is no clear reason why nonsterile gloves might be less effective in preventing infection in environments with lower infection rates.

This was not a double-blinded study, and clinicians might change their behavior during a procedure depending on the type of gloves they are wearing. The sterile gloves used in this study contained powder, while the nonsterile gloves were powderless, but this variable is not known to affect infection rates. A study of Mohs surgery avoided this variable by only using powderless gloves; outcomes were similar in terms of the difference in infection rate between sterile and nonsterile gloves.⁴

Continue for challenges to implementation >>

CHALLENGES TO IMPLEMENTATION 
Ingrained habits can be hard to change
Tradition and training die hard. While multiple studies in several settings have found nonsterile gloves to be noninferior to sterile gloves in preventing surgical site infection after minor skin surgeries, this single study in the primary care office setting may not be enough to sway clinicians from ingrained habits.

REFERENCES 
1. Heal C, Sriharan S, Buttner PG, et al. Comparing non-sterile to sterile gloves for minor surgery: a prospective randomized controlled non-inferiority trial. Med J Aust. 2015;202:27-31.
2. Perelman VS, Francis GJ, Rutledge T, et al. Sterile versus nonsterile gloves for repair of uncomplicated lacerations in the emergency department: a randomized controlled trial. Ann Emerg Med. 2004;43:362-370.
3. Mehta D, Chambers N, Adams B, et al. Comparison of the prevalence of surgical site infection with use of sterile versus nonsterile gloves for resection and reconstruction during Mohs surgery. Dermatol Surg. 2014;40: 234-239.
4. Xia Y, Cho S, Greenway HT, et al. Infection rates of wound repairs during Mohs micrographic surgery using sterile versus nonsterile gloves: a prospective randomized pilot study. Dermatol Surg. 2011;37:651-656.
5. Mangram AJ, Horan TC, Pearson ML, et al. Guideline for prevention of surgical site infection, 1999. Centers for Disease Control and Prevention (CDC) Hospital Infection Control Practices Advisory Committee. Am J Infect Control. 1999;27:97-132.
6. National Institute for Health and Care Excellence. Surgical site infection: prevention and treatment of surgical site infection. www.nice.org.uk/guidance/cg74/chapter/1-recommendations. Accessed November 17, 2015.
7. National Health and Medical Research Council. Australian Guidelines for the Prevention and Control of Infection in Healthcare (2010). www.nhmrc.gov.au/book/html-australian-guideline-sprevention-and-control-infection-healthcare-2010. Accessed November 17, 2015.
8. American Academy of Dermatology. Clinical guidelines. www.aad.org/education/clinical-guidelines. Accessed November 17, 2015.
9. Zuber TJ. Fusiform excision. Am Fam Physician. 2003;67:1539-1544.
10. Heal C, Buettner P, Browning S. Risk factors for wound infection after minor surgery in general practice. Med J Aust. 2006;18:255-258.

ACKNOWLEDGEMENT
The PURLs Surveillance System was supported in part by Grant Number UL1RR024999 from the National Center For Research Resources, a Clinical Translational Science Award to the University of Chicago. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Center For Research Resources or the National Institutes of Health.

Copyright © 2015. The Family Physicians Inquiries Network. All rights reserved.

Reprinted with permission from the Family Physicians Inquiries Network and The Journal of Family Practice. 2015;64(11):723-724, 727. 

PRACTICE CHANGER
Consider using nonsterile gloves during minor skin excisions (even those requiring sutures), because the infection rate is not increased compared to using sterile gloves.¹

STRENGTH OF RECOMMENDATION
B: Based on a randomized controlled trial (RCT) conducted in a primary care practice.¹

ILLUSTRATIVE CASE
A 50-year-old man comes to your office to have a mole removed from his arm. You decide to excise the lesion in your office today. Do you need to use sterile gloves for this procedure, or can you use gloves from the clean nonsterile box in the exam room?

Nonsterile gloves are readily available during a typical office visit and cost up to a dollar less per pair than sterile gloves.^1-3 Studies conducted in settings other than primary care offices have shown that nonsterile gloves do not increase the risk for infection during several types of minor skin procedures.

A partially blinded RCT in an emergency department found no significant difference in infection rates between the use of sterile (6.1%) and nonsterile (4.4%) gloves during laceration repairs.² Similarly, a small RCT in an outpatient dermatology clinic and a larger prospective trial by a Mohs dermatologist showed that infection rates were not increased after Mohs surgery using nonsterile (0.49%) versus sterile (0.50%) gloves.^3,4

Guidelines on the use of sterile versus nonsterile gloves for minor skin excisions in outpatient primary care are difficult to come by. Current guidelines from the CDC and other agencies regarding surgical site infections are broad and focus on the operating room environment.^5-7

The American Academy of Dermatology is working on a guideline for treatment of nonmelanoma skin cancer, due out this winter, which may provide additional guidance.⁸ A 2003 review instructed primary care providers to use sterile gloves for excisional skin biopsies that require sutures.⁹

The 2015 study by Heal et al¹ appears to be the first RCT to address the question of sterile versus nonsterile glove use for minor skin excisions in a primary care outpatient practice.

Continue for study summary >>

STUDY SUMMARY 
Nonsterile is not inferior
Heal et al¹ conducted a prospective, noninferiority RCT to compare the incidence of infection after minor skin surgery performed by six physicians from a single general practice in Australia using sterile versus nonsterile clean gloves. They evaluated 576 consecutive patients who presented for skin excision between June 2012 and March 2013. Eighty-three patients were excluded because they had a latex allergy, were using oral antibiotics or immunosuppressive drugs, or required a skin flap procedure or excision of a sebaceous cyst. The physicians followed a standard process for performing the procedures and did not use topical antibiotics or antiseptic cleansing after the procedure.

The primary outcome was surgical site infection within 30 days of the excision, defined as purulent discharge; pain or tenderness; localized swelling, redness, or heat at the site; or a diagnosis of skin or soft-tissue infection by a general practitioner. The clinicians who assessed for infection were blinded to the patient’s assignment to the sterile or nonsterile glove group, and a stitch abscess was not counted as an infection.

The patients’ mean age was 65, and 59% were men. At baseline, there were no large differences between patients in the sterile and nonsterile glove groups in terms of smoking status, anticoagulant or corticosteroid use, diabetes, excision site, size of excision, and median days until removal of sutures. The lesions were identified histologically as nevus or seborrheic keratosis; skin cancer and precursor; or other.

The incidence of infection in the nonsterile gloves group was 21/241 (8.7%) versus 22/237 in the control group (9.3%). The confidence interval (CI; 95%) for the difference in infection rate (–0.6%) was –4.0% to 2.9%—significantly below the predetermined noninferiority margin of 7%. In a sensitivity analysis of patients lost to follow-up (15 patients, 3%) that assumed all of these patients were without infection, or with infection, the CI was still below the noninferiority margin of 7%. The per-protocol analysis showed similar results.

Continue for what's new >>

WHAT’S NEW 
New evidence questions the need for sterile gloves for in-office excisions
Heal et al¹ demonstrated that in a primary care setting, nonsterile gloves are not inferior to sterile gloves for excisional procedures that require sutures. While standard practice has many family practice providers using sterile gloves for these procedures, this study promotes changing this ­behavior.

Continue for caveats >>

CAVEATS 
High infection rate, other factors may limit generalizability
The overall rate of infection in this study (9%) was higher than that found in the studies from emergency medicine and dermatology literature cited earlier.^2-4 A similarly high infection rate has been found in other studies of minor surgery by Heal et al, including a 2006 study that showed a wound infection rate of 8.6%.¹⁰ The significance of the higher infection rate is unknown, but there is no clear reason why nonsterile gloves might be less effective in preventing infection in environments with lower infection rates.

This was not a double-blinded study, and clinicians might change their behavior during a procedure depending on the type of gloves they are wearing. The sterile gloves used in this study contained powder, while the nonsterile gloves were powderless, but this variable is not known to affect infection rates. A study of Mohs surgery avoided this variable by only using powderless gloves; outcomes were similar in terms of the difference in infection rate between sterile and nonsterile gloves.⁴

Continue for challenges to implementation >>

CHALLENGES TO IMPLEMENTATION 
Ingrained habits can be hard to change
Tradition and training die hard. While multiple studies in several settings have found nonsterile gloves to be noninferior to sterile gloves in preventing surgical site infection after minor skin surgeries, this single study in the primary care office setting may not be enough to sway clinicians from ingrained habits.

REFERENCES 
1. Heal C, Sriharan S, Buttner PG, et al. Comparing non-sterile to sterile gloves for minor surgery: a prospective randomized controlled non-inferiority trial. Med J Aust. 2015;202:27-31.
2. Perelman VS, Francis GJ, Rutledge T, et al. Sterile versus nonsterile gloves for repair of uncomplicated lacerations in the emergency department: a randomized controlled trial. Ann Emerg Med. 2004;43:362-370.
3. Mehta D, Chambers N, Adams B, et al. Comparison of the prevalence of surgical site infection with use of sterile versus nonsterile gloves for resection and reconstruction during Mohs surgery. Dermatol Surg. 2014;40: 234-239.
4. Xia Y, Cho S, Greenway HT, et al. Infection rates of wound repairs during Mohs micrographic surgery using sterile versus nonsterile gloves: a prospective randomized pilot study. Dermatol Surg. 2011;37:651-656.
5. Mangram AJ, Horan TC, Pearson ML, et al. Guideline for prevention of surgical site infection, 1999. Centers for Disease Control and Prevention (CDC) Hospital Infection Control Practices Advisory Committee. Am J Infect Control. 1999;27:97-132.
6. National Institute for Health and Care Excellence. Surgical site infection: prevention and treatment of surgical site infection. www.nice.org.uk/guidance/cg74/chapter/1-recommendations. Accessed November 17, 2015.
7. National Health and Medical Research Council. Australian Guidelines for the Prevention and Control of Infection in Healthcare (2010). www.nhmrc.gov.au/book/html-australian-guideline-sprevention-and-control-infection-healthcare-2010. Accessed November 17, 2015.
8. American Academy of Dermatology. Clinical guidelines. www.aad.org/education/clinical-guidelines. Accessed November 17, 2015.
9. Zuber TJ. Fusiform excision. Am Fam Physician. 2003;67:1539-1544.
10. Heal C, Buettner P, Browning S. Risk factors for wound infection after minor surgery in general practice. Med J Aust. 2006;18:255-258.

ACKNOWLEDGEMENT
The PURLs Surveillance System was supported in part by Grant Number UL1RR024999 from the National Center For Research Resources, a Clinical Translational Science Award to the University of Chicago. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Center For Research Resources or the National Institutes of Health.

Copyright © 2015. The Family Physicians Inquiries Network. All rights reserved.

Reprinted with permission from the Family Physicians Inquiries Network and The Journal of Family Practice. 2015;64(11):723-724, 727. 

Illustrative case

A 50-year-old man comes to your office to have a mole removed from his arm. You decide to excise the lesion in your office today. Do you need to use sterile gloves for this procedure, or can you use gloves from the clean non-sterile box in the exam room?

Non-sterile gloves are readily available during a typical office visit and cost up to a dollar less per pair than sterile gloves.^1-3 Studies conducted in settings other than primary care offices have shown that non-sterile gloves do not increase the risk of infection during several types of minor skin procedures.

A partially blinded, randomized controlled trial (RCT) in an emergency department found no significant difference in infection rates between the use of sterile (6.1%) vs non-sterile (4.4%) gloves during laceration repairs.² Similarly, a small RCT in an outpatient dermatology clinic and a larger prospective trial by a Mohs dermatologist showed that infection rates were not increased after Mohs surgery using non-sterile (0.49%) vs sterile (0.50%) gloves.^3,4

Guidelines on the use of sterile vs non-sterile gloves for minor skin excisions in outpatient primary care are difficult to come by. Current guidelines from the Centers for Disease Control and Prevention (CDC) and other agencies regarding surgical site infections are broad and focus on the operating room environment.^5-7

The American Academy of Dermatology is working on a guideline for treatment of non-melanoma skin cancer that’s due out this winter, and this may provide additional guidance.⁸ A 2003 review instructed primary care physicians to use sterile gloves for excisional skin biopsies that require sutures.⁹

The 2015 study by Heal et al¹ appears to be the first RCT to address the question of sterile vs non-sterile glove use for minor skin excisions in a primary care outpatient practice.

STUDY SUMMARY: Non-sterile gloves are not inferior to sterile gloves

Heal et al¹ conducted a prospective, randomized, controlled, noninferiority trial to compare the incidence of infection after minor skin surgery performed by 6 physicians from a single general practice in Australia using sterile vs non-sterile clean gloves. They evaluated 576 consecutive patients who presented for skin excision between June 2012 and March 2013. Eighty-three patients were excluded because they had a latex allergy, were using oral antibiotics or immunosuppressive drugs, or required a skin flap procedure or excision of a sebaceous cyst. The physicians followed a standard process for performing the procedures and did not use topical antibiotics or antiseptic cleansing after the procedure.

The primary outcome was surgical site infection within 30 days of the excision, defined as purulent discharge, pain or tenderness, localized swelling or redness or heat at the site, or a diagnosis of skin or soft tissue infection by a general practitioner. The clinicians who assessed for infection were blinded to the patient’s assignment to the sterile or non-sterile glove group, and a stitch abscess was not counted as an infection.

Tradition and training die hard. A single study in the primary care office setting may not be enough to sway family physicians from ingrained habits.

The patients’ mean age was 65 years and 59% were men. At baseline, there were no large differences between patients in the sterile and non-sterile glove groups in terms of smoking status, anticoagulant or steroid use, diabetes, excision site, size of excision, and median days until removal of sutures. The lesions were identified histologically as nevus or seborrheic keratosis, skin cancer and precursor, or other.

The incidence of infection in the non-sterile gloves group was 21/241 (8.7%; 95% confidence interval [CI], 4.9%-12.6%) vs 22/237 in the control group (9.3%; 95% CI, 7.4%-11.1%). The CI (95%) for the difference in infection rate (-0.6%) was -4.0% to 2.9%. This was significantly below the predetermined noninferiority margin of 7%. In a sensitivity analysis of patients lost to follow-up (15 patients, 3%) that assumed all of these patients were without infection, or with infection, the CI was still below the noninferiority margin of 7%. The per-protocol analysis showed similar results.

WHAT'S NEW: New evidence questions the need for sterile gloves for in-office excisions

Heal et al¹ demonstrated that in a primary care setting, non-sterile gloves are not inferior to sterile gloves for performing excisional procedures that require sutures. While standard practice has many family physicians using sterile gloves for these procedures, this study promotes changing this behavior.

CAVEATS: A high infection rate, other factors might limit generalizability 

The overall rate of infection in this study (9%) was higher than that found in the studies from emergency medicine and dermatology literature cited earlier.^2-4 A similarly high infection rate has been found in other studies of minor surgery by Heal et al, including a 2006 study that showed a wound infection rate of 8.6%.¹⁰ The significance of the higher infection rate is unknown, but there is no clear reason why non-sterile gloves might be less effective in preventing infection in environments with lower infection rates.

This was not a double-blinded study, and physicians might change their behavior during a procedure depending on the type of gloves they are wearing. The sterile gloves used in this study contained powder, while the non-sterile gloves were powderless, but this variable is not known to affect infection rates. A study of Mohs surgery avoided this variable by only using powderless gloves, and had similar outcomes in terms of the difference in infection rate between sterile and non-sterile gloves.⁴

CHALLENGES TO IMPLEMENTATION:  Ingrained habits can be hard to change

Tradition and training die hard. While multiple studies in several settings have found non-sterile gloves are non-inferior to sterile gloves in preventing surgical site infection after minor skin surgeries, this single study in the primary care office setting may not be enough to sway family physicians from ingrained habits.

ACKNOWLEDGEMENT 
The PURLs Surveillance System was supported in part by Grant Number UL1RR024999 from the National Center For Research Resources, a Clinical Translational Science Award to the University of Chicago. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Center For Research Resources or the National Institutes of Health.

Illustrative case

A 50-year-old man comes to your office to have a mole removed from his arm. You decide to excise the lesion in your office today. Do you need to use sterile gloves for this procedure, or can you use gloves from the clean non-sterile box in the exam room?

Non-sterile gloves are readily available during a typical office visit and cost up to a dollar less per pair than sterile gloves.^1-3 Studies conducted in settings other than primary care offices have shown that non-sterile gloves do not increase the risk of infection during several types of minor skin procedures.

A partially blinded, randomized controlled trial (RCT) in an emergency department found no significant difference in infection rates between the use of sterile (6.1%) vs non-sterile (4.4%) gloves during laceration repairs.² Similarly, a small RCT in an outpatient dermatology clinic and a larger prospective trial by a Mohs dermatologist showed that infection rates were not increased after Mohs surgery using non-sterile (0.49%) vs sterile (0.50%) gloves.^3,4

Guidelines on the use of sterile vs non-sterile gloves for minor skin excisions in outpatient primary care are difficult to come by. Current guidelines from the Centers for Disease Control and Prevention (CDC) and other agencies regarding surgical site infections are broad and focus on the operating room environment.^5-7

The American Academy of Dermatology is working on a guideline for treatment of non-melanoma skin cancer that’s due out this winter, and this may provide additional guidance.⁸ A 2003 review instructed primary care physicians to use sterile gloves for excisional skin biopsies that require sutures.⁹

The 2015 study by Heal et al¹ appears to be the first RCT to address the question of sterile vs non-sterile glove use for minor skin excisions in a primary care outpatient practice.

STUDY SUMMARY: Non-sterile gloves are not inferior to sterile gloves

Heal et al¹ conducted a prospective, randomized, controlled, noninferiority trial to compare the incidence of infection after minor skin surgery performed by 6 physicians from a single general practice in Australia using sterile vs non-sterile clean gloves. They evaluated 576 consecutive patients who presented for skin excision between June 2012 and March 2013. Eighty-three patients were excluded because they had a latex allergy, were using oral antibiotics or immunosuppressive drugs, or required a skin flap procedure or excision of a sebaceous cyst. The physicians followed a standard process for performing the procedures and did not use topical antibiotics or antiseptic cleansing after the procedure.

The primary outcome was surgical site infection within 30 days of the excision, defined as purulent discharge, pain or tenderness, localized swelling or redness or heat at the site, or a diagnosis of skin or soft tissue infection by a general practitioner. The clinicians who assessed for infection were blinded to the patient’s assignment to the sterile or non-sterile glove group, and a stitch abscess was not counted as an infection.

Tradition and training die hard. A single study in the primary care office setting may not be enough to sway family physicians from ingrained habits.

The patients’ mean age was 65 years and 59% were men. At baseline, there were no large differences between patients in the sterile and non-sterile glove groups in terms of smoking status, anticoagulant or steroid use, diabetes, excision site, size of excision, and median days until removal of sutures. The lesions were identified histologically as nevus or seborrheic keratosis, skin cancer and precursor, or other.

The incidence of infection in the non-sterile gloves group was 21/241 (8.7%; 95% confidence interval [CI], 4.9%-12.6%) vs 22/237 in the control group (9.3%; 95% CI, 7.4%-11.1%). The CI (95%) for the difference in infection rate (-0.6%) was -4.0% to 2.9%. This was significantly below the predetermined noninferiority margin of 7%. In a sensitivity analysis of patients lost to follow-up (15 patients, 3%) that assumed all of these patients were without infection, or with infection, the CI was still below the noninferiority margin of 7%. The per-protocol analysis showed similar results.

WHAT'S NEW: New evidence questions the need for sterile gloves for in-office excisions

Heal et al¹ demonstrated that in a primary care setting, non-sterile gloves are not inferior to sterile gloves for performing excisional procedures that require sutures. While standard practice has many family physicians using sterile gloves for these procedures, this study promotes changing this behavior.

CAVEATS: A high infection rate, other factors might limit generalizability 

The overall rate of infection in this study (9%) was higher than that found in the studies from emergency medicine and dermatology literature cited earlier.^2-4 A similarly high infection rate has been found in other studies of minor surgery by Heal et al, including a 2006 study that showed a wound infection rate of 8.6%.¹⁰ The significance of the higher infection rate is unknown, but there is no clear reason why non-sterile gloves might be less effective in preventing infection in environments with lower infection rates.

This was not a double-blinded study, and physicians might change their behavior during a procedure depending on the type of gloves they are wearing. The sterile gloves used in this study contained powder, while the non-sterile gloves were powderless, but this variable is not known to affect infection rates. A study of Mohs surgery avoided this variable by only using powderless gloves, and had similar outcomes in terms of the difference in infection rate between sterile and non-sterile gloves.⁴

CHALLENGES TO IMPLEMENTATION:  Ingrained habits can be hard to change

Tradition and training die hard. While multiple studies in several settings have found non-sterile gloves are non-inferior to sterile gloves in preventing surgical site infection after minor skin surgeries, this single study in the primary care office setting may not be enough to sway family physicians from ingrained habits.

ACKNOWLEDGEMENT 
The PURLs Surveillance System was supported in part by Grant Number UL1RR024999 from the National Center For Research Resources, a Clinical Translational Science Award to the University of Chicago. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Center For Research Resources or the National Institutes of Health.

Illustrative case

A 50-year-old man comes to your office to have a mole removed from his arm. You decide to excise the lesion in your office today. Do you need to use sterile gloves for this procedure, or can you use gloves from the clean non-sterile box in the exam room?

Non-sterile gloves are readily available during a typical office visit and cost up to a dollar less per pair than sterile gloves.^1-3 Studies conducted in settings other than primary care offices have shown that non-sterile gloves do not increase the risk of infection during several types of minor skin procedures.

A partially blinded, randomized controlled trial (RCT) in an emergency department found no significant difference in infection rates between the use of sterile (6.1%) vs non-sterile (4.4%) gloves during laceration repairs.² Similarly, a small RCT in an outpatient dermatology clinic and a larger prospective trial by a Mohs dermatologist showed that infection rates were not increased after Mohs surgery using non-sterile (0.49%) vs sterile (0.50%) gloves.^3,4

Guidelines on the use of sterile vs non-sterile gloves for minor skin excisions in outpatient primary care are difficult to come by. Current guidelines from the Centers for Disease Control and Prevention (CDC) and other agencies regarding surgical site infections are broad and focus on the operating room environment.^5-7

The American Academy of Dermatology is working on a guideline for treatment of non-melanoma skin cancer that’s due out this winter, and this may provide additional guidance.⁸ A 2003 review instructed primary care physicians to use sterile gloves for excisional skin biopsies that require sutures.⁹

The 2015 study by Heal et al¹ appears to be the first RCT to address the question of sterile vs non-sterile glove use for minor skin excisions in a primary care outpatient practice.

STUDY SUMMARY: Non-sterile gloves are not inferior to sterile gloves

Heal et al¹ conducted a prospective, randomized, controlled, noninferiority trial to compare the incidence of infection after minor skin surgery performed by 6 physicians from a single general practice in Australia using sterile vs non-sterile clean gloves. They evaluated 576 consecutive patients who presented for skin excision between June 2012 and March 2013. Eighty-three patients were excluded because they had a latex allergy, were using oral antibiotics or immunosuppressive drugs, or required a skin flap procedure or excision of a sebaceous cyst. The physicians followed a standard process for performing the procedures and did not use topical antibiotics or antiseptic cleansing after the procedure.

The primary outcome was surgical site infection within 30 days of the excision, defined as purulent discharge, pain or tenderness, localized swelling or redness or heat at the site, or a diagnosis of skin or soft tissue infection by a general practitioner. The clinicians who assessed for infection were blinded to the patient’s assignment to the sterile or non-sterile glove group, and a stitch abscess was not counted as an infection.

Tradition and training die hard. A single study in the primary care office setting may not be enough to sway family physicians from ingrained habits.

The patients’ mean age was 65 years and 59% were men. At baseline, there were no large differences between patients in the sterile and non-sterile glove groups in terms of smoking status, anticoagulant or steroid use, diabetes, excision site, size of excision, and median days until removal of sutures. The lesions were identified histologically as nevus or seborrheic keratosis, skin cancer and precursor, or other.

The incidence of infection in the non-sterile gloves group was 21/241 (8.7%; 95% confidence interval [CI], 4.9%-12.6%) vs 22/237 in the control group (9.3%; 95% CI, 7.4%-11.1%). The CI (95%) for the difference in infection rate (-0.6%) was -4.0% to 2.9%. This was significantly below the predetermined noninferiority margin of 7%. In a sensitivity analysis of patients lost to follow-up (15 patients, 3%) that assumed all of these patients were without infection, or with infection, the CI was still below the noninferiority margin of 7%. The per-protocol analysis showed similar results.

WHAT'S NEW: New evidence questions the need for sterile gloves for in-office excisions

Heal et al¹ demonstrated that in a primary care setting, non-sterile gloves are not inferior to sterile gloves for performing excisional procedures that require sutures. While standard practice has many family physicians using sterile gloves for these procedures, this study promotes changing this behavior.

CAVEATS: A high infection rate, other factors might limit generalizability 

The overall rate of infection in this study (9%) was higher than that found in the studies from emergency medicine and dermatology literature cited earlier.^2-4 A similarly high infection rate has been found in other studies of minor surgery by Heal et al, including a 2006 study that showed a wound infection rate of 8.6%.¹⁰ The significance of the higher infection rate is unknown, but there is no clear reason why non-sterile gloves might be less effective in preventing infection in environments with lower infection rates.

This was not a double-blinded study, and physicians might change their behavior during a procedure depending on the type of gloves they are wearing. The sterile gloves used in this study contained powder, while the non-sterile gloves were powderless, but this variable is not known to affect infection rates. A study of Mohs surgery avoided this variable by only using powderless gloves, and had similar outcomes in terms of the difference in infection rate between sterile and non-sterile gloves.⁴

CHALLENGES TO IMPLEMENTATION:  Ingrained habits can be hard to change

Tradition and training die hard. While multiple studies in several settings have found non-sterile gloves are non-inferior to sterile gloves in preventing surgical site infection after minor skin surgeries, this single study in the primary care office setting may not be enough to sway family physicians from ingrained habits.

ACKNOWLEDGEMENT 
The PURLs Surveillance System was supported in part by Grant Number UL1RR024999 from the National Center For Research Resources, a Clinical Translational Science Award to the University of Chicago. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Center For Research Resources or the National Institutes of Health.

ILLUSTRATIVE CASE

A 60-year-old assembly line worker reports bilateral hand numbness and tingling that frequently awaken her at night. What is the best office test to determine if she has CTS?

CTS is one of the most common causes of disability in the United States.² Among patients with hand paresthesias, one in 5 has CTS.² Factory workers whose jobs involve repetitive hand movements, females, and the elderly are at increased risk.³ If left untreated, the symptoms are likely to become constant, with thenar muscle wasting and weakness.

Traditional diagnostic test has only 50% sensitivity
In the traditional Phalen’s test (TPT)—commonly used in an office setting—the patient holds his or her wrists in a position of fixed flexion for one minute. The onset of paresthesias is considered a positive result.

The TPT was found in the study reported here to be 100% specific;¹ however, other studies have found a wider range of specificity (33%-86%).⁴ The TPT has a sensitivity of only 50%, which increases the risk that cases of CTS will be missed. This is an important consideration because establishing a diagnosis early in the course of CTS has been shown to minimize disability.⁵

STUDY SUMMARY: Modified Phalen’s has higher sensitivity

Bilkis et al developed a modified Phalen’s test (MPT) and compared it with the TPT, as well as with electrodiagnostic studies (EDS)—the gold standard for CTS diagnosis. The MPT begins with the TPT position and adds sensory testing with a Semmes-Weinstein 2.83-unit monofilament.

See how the modified Phalen’s test is done

Courtesy of Clinically Relevant Technologies

The filament is applied perpendicular to the palmar and lateral surface of each distal finger 3 times, with enough pressure to bend the monofilament. In this study, the test was considered positive if the patient did not feel the monofilament in any finger along the distribution of the median nerve. The MPT was negative if the patient correctly reported being touched along this distribution. The fifth, or “pinkie,” finger, which is less likely to be affected by CTS, was used as a control.

Participants in the study were adult patients—mostly women between the ages of 27 and 88 years—at a neurology clinic. Exclusion criteria included cervical radiculopathy, a history of stroke, diabetes mellitus, and concomitant neck injury. A total of 66 hands (and 37 participants) underwent TPT and MPT testing by trained examiners, followed by EDS to confirm the findings.

EDS found evidence of CTS in 46 of the 66 hands studied. The MPT correctly identified 39 of the 46, while the TPT correctly identified 23. Both the traditional and the modified Phalen’s were found to be 100% specific, but the sensitivity of the MPT was 85% (95% confidence interval [CI], 71%-93%), compared with 50% (95% CI, 35%-65%) for the TPT.

WHAT’S NEW: Better results can be achieved in seconds

The addition of monofilament testing to the TPT increases the sensitivity in identifying CTS. The MPT is simple to learn (watch the video on jfponline.com) and, based on our observations, adds only about 10 to 15 seconds to the clinical exam.

CAVEATS: Modification is untested in primary care

A diagnosis of CTS is rarely made on the basis of one test, but rather on a set of signs, symptoms, and physical exam maneuvers. The added value of the MPT needs to be evaluated in the larger context of the comprehensive clinical examination for CTS.⁶

Notably, the study participants were seen in a neurology clinic, which suggests that they may have had more advanced CTS than typical primary care patients. That would help explain the 100% specificity of both the traditional and modified tests reported by the researchers. The sensitivity of the MPT may therefore be lower in a family physician’s office because the spectrum of disease may be wider. Another study is needed to evaluate the performance of the MPT in a primary care setting.

The monofilament used (Semmes-Weinstein 2.83) is not the same as the typical 5.07 (10-g) monofilament used in diabetic foot screenings. Using this heavier monofilament with a stronger pressure point would likely decrease the sensitivity of the MPT.

CHALLENGES TO IMPLEMENTATION: Taking the time, obtaining the monofilament

Additional time to obtain the correct monofilament and administer the MPT are the key challenges to implementation.

Acknowledgement

The PURLs Surveillance System was supported in part by Grant Number UL1RR024999 from the National Center for Research Resources, a Clinical Translational Science Award to the University of Chicago. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Center for Research Resources or the National Institutes of Health.

ILLUSTRATIVE CASE

A 60-year-old assembly line worker reports bilateral hand numbness and tingling that frequently awaken her at night. What is the best office test to determine if she has CTS?

CTS is one of the most common causes of disability in the United States.² Among patients with hand paresthesias, one in 5 has CTS.² Factory workers whose jobs involve repetitive hand movements, females, and the elderly are at increased risk.³ If left untreated, the symptoms are likely to become constant, with thenar muscle wasting and weakness.

Traditional diagnostic test has only 50% sensitivity
In the traditional Phalen’s test (TPT)—commonly used in an office setting—the patient holds his or her wrists in a position of fixed flexion for one minute. The onset of paresthesias is considered a positive result.

The TPT was found in the study reported here to be 100% specific;¹ however, other studies have found a wider range of specificity (33%-86%).⁴ The TPT has a sensitivity of only 50%, which increases the risk that cases of CTS will be missed. This is an important consideration because establishing a diagnosis early in the course of CTS has been shown to minimize disability.⁵

STUDY SUMMARY: Modified Phalen’s has higher sensitivity

Bilkis et al developed a modified Phalen’s test (MPT) and compared it with the TPT, as well as with electrodiagnostic studies (EDS)—the gold standard for CTS diagnosis. The MPT begins with the TPT position and adds sensory testing with a Semmes-Weinstein 2.83-unit monofilament.

See how the modified Phalen’s test is done

Courtesy of Clinically Relevant Technologies

The filament is applied perpendicular to the palmar and lateral surface of each distal finger 3 times, with enough pressure to bend the monofilament. In this study, the test was considered positive if the patient did not feel the monofilament in any finger along the distribution of the median nerve. The MPT was negative if the patient correctly reported being touched along this distribution. The fifth, or “pinkie,” finger, which is less likely to be affected by CTS, was used as a control.

Participants in the study were adult patients—mostly women between the ages of 27 and 88 years—at a neurology clinic. Exclusion criteria included cervical radiculopathy, a history of stroke, diabetes mellitus, and concomitant neck injury. A total of 66 hands (and 37 participants) underwent TPT and MPT testing by trained examiners, followed by EDS to confirm the findings.

EDS found evidence of CTS in 46 of the 66 hands studied. The MPT correctly identified 39 of the 46, while the TPT correctly identified 23. Both the traditional and the modified Phalen’s were found to be 100% specific, but the sensitivity of the MPT was 85% (95% confidence interval [CI], 71%-93%), compared with 50% (95% CI, 35%-65%) for the TPT.

WHAT’S NEW: Better results can be achieved in seconds

The addition of monofilament testing to the TPT increases the sensitivity in identifying CTS. The MPT is simple to learn (watch the video on jfponline.com) and, based on our observations, adds only about 10 to 15 seconds to the clinical exam.

CAVEATS: Modification is untested in primary care

A diagnosis of CTS is rarely made on the basis of one test, but rather on a set of signs, symptoms, and physical exam maneuvers. The added value of the MPT needs to be evaluated in the larger context of the comprehensive clinical examination for CTS.⁶

Notably, the study participants were seen in a neurology clinic, which suggests that they may have had more advanced CTS than typical primary care patients. That would help explain the 100% specificity of both the traditional and modified tests reported by the researchers. The sensitivity of the MPT may therefore be lower in a family physician’s office because the spectrum of disease may be wider. Another study is needed to evaluate the performance of the MPT in a primary care setting.

The monofilament used (Semmes-Weinstein 2.83) is not the same as the typical 5.07 (10-g) monofilament used in diabetic foot screenings. Using this heavier monofilament with a stronger pressure point would likely decrease the sensitivity of the MPT.

CHALLENGES TO IMPLEMENTATION: Taking the time, obtaining the monofilament

Additional time to obtain the correct monofilament and administer the MPT are the key challenges to implementation.

Acknowledgement

The PURLs Surveillance System was supported in part by Grant Number UL1RR024999 from the National Center for Research Resources, a Clinical Translational Science Award to the University of Chicago. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Center for Research Resources or the National Institutes of Health.

ILLUSTRATIVE CASE

A 60-year-old assembly line worker reports bilateral hand numbness and tingling that frequently awaken her at night. What is the best office test to determine if she has CTS?

CTS is one of the most common causes of disability in the United States.² Among patients with hand paresthesias, one in 5 has CTS.² Factory workers whose jobs involve repetitive hand movements, females, and the elderly are at increased risk.³ If left untreated, the symptoms are likely to become constant, with thenar muscle wasting and weakness.

Traditional diagnostic test has only 50% sensitivity
In the traditional Phalen’s test (TPT)—commonly used in an office setting—the patient holds his or her wrists in a position of fixed flexion for one minute. The onset of paresthesias is considered a positive result.

The TPT was found in the study reported here to be 100% specific;¹ however, other studies have found a wider range of specificity (33%-86%).⁴ The TPT has a sensitivity of only 50%, which increases the risk that cases of CTS will be missed. This is an important consideration because establishing a diagnosis early in the course of CTS has been shown to minimize disability.⁵

STUDY SUMMARY: Modified Phalen’s has higher sensitivity

Bilkis et al developed a modified Phalen’s test (MPT) and compared it with the TPT, as well as with electrodiagnostic studies (EDS)—the gold standard for CTS diagnosis. The MPT begins with the TPT position and adds sensory testing with a Semmes-Weinstein 2.83-unit monofilament.

See how the modified Phalen’s test is done

Courtesy of Clinically Relevant Technologies

The filament is applied perpendicular to the palmar and lateral surface of each distal finger 3 times, with enough pressure to bend the monofilament. In this study, the test was considered positive if the patient did not feel the monofilament in any finger along the distribution of the median nerve. The MPT was negative if the patient correctly reported being touched along this distribution. The fifth, or “pinkie,” finger, which is less likely to be affected by CTS, was used as a control.

Participants in the study were adult patients—mostly women between the ages of 27 and 88 years—at a neurology clinic. Exclusion criteria included cervical radiculopathy, a history of stroke, diabetes mellitus, and concomitant neck injury. A total of 66 hands (and 37 participants) underwent TPT and MPT testing by trained examiners, followed by EDS to confirm the findings.

EDS found evidence of CTS in 46 of the 66 hands studied. The MPT correctly identified 39 of the 46, while the TPT correctly identified 23. Both the traditional and the modified Phalen’s were found to be 100% specific, but the sensitivity of the MPT was 85% (95% confidence interval [CI], 71%-93%), compared with 50% (95% CI, 35%-65%) for the TPT.

WHAT’S NEW: Better results can be achieved in seconds

The addition of monofilament testing to the TPT increases the sensitivity in identifying CTS. The MPT is simple to learn (watch the video on jfponline.com) and, based on our observations, adds only about 10 to 15 seconds to the clinical exam.

CAVEATS: Modification is untested in primary care

A diagnosis of CTS is rarely made on the basis of one test, but rather on a set of signs, symptoms, and physical exam maneuvers. The added value of the MPT needs to be evaluated in the larger context of the comprehensive clinical examination for CTS.⁶

Notably, the study participants were seen in a neurology clinic, which suggests that they may have had more advanced CTS than typical primary care patients. That would help explain the 100% specificity of both the traditional and modified tests reported by the researchers. The sensitivity of the MPT may therefore be lower in a family physician’s office because the spectrum of disease may be wider. Another study is needed to evaluate the performance of the MPT in a primary care setting.

The monofilament used (Semmes-Weinstein 2.83) is not the same as the typical 5.07 (10-g) monofilament used in diabetic foot screenings. Using this heavier monofilament with a stronger pressure point would likely decrease the sensitivity of the MPT.

CHALLENGES TO IMPLEMENTATION: Taking the time, obtaining the monofilament

Additional time to obtain the correct monofilament and administer the MPT are the key challenges to implementation.

Acknowledgement

The PURLs Surveillance System was supported in part by Grant Number UL1RR024999 from the National Center for Research Resources, a Clinical Translational Science Award to the University of Chicago. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Center for Research Resources or the National Institutes of Health.

ILLUSTRATIVE CASES

A 65-year-old obese man with high blood pressure comes in for a complete physical and asks if he should have the “blood test for cancer.” He had a normal prostate specific antigen (PSA) the last time he was tested, but that was 10 years ago. What should you tell him?

A 55-year-old man schedules a routine check-up and requests a PSA test. His last test, at age 50, was normal. The patient has no known medical problems and no family history of prostate cancer, and he exercises regularly and doesn’t smoke. How should you respond to his request for a PSA test?

Prostate cancer is the second leading cause of cancer deaths among men in the United States, after lung cancer. One in 6 American men will be diagnosed with prostate cancer; for about 3% of them, the cancer will be fatal.^3,4

Widespread testing without evidence of efficacy
The PSA test was approved by the US Food and Drug Administration (FDA) in 1986.⁵ Its potential to detect early prostate cancer in the hope of decreasing morbidity and mortality led to widespread PSA screening in the 1990s, before data on the efficacy of routine screening existed.

By 2002, only one low-quality RCT that compared screening with no screening had been published. The investigators concluded that screening resulted in lower mortality rates, but a subsequent (and superior) intention-to-treat analysis showed no mortality benefit.⁶ Two large RCTs, both published in 2009, reported conflicting results.^7,8

The European Randomized Study of Screening for Prostate Cancer (ERSPC) enrolled 182,000 men ages 50 to 74 years and randomized them to either PSA screening every 4 years or no screening. Prostate cancer-specific mortality was 20% lower for those in the screening group compared with the no-screening group; however, the absolute risk reduction was only 0.71 deaths per 1000 men.⁷

The US Prostate, Lung, Colorectal, Ovarian Cancer (PLCO) Screening Trial randomized 77,000 men ages 55 to 74 years to either annual PSA and digital rectal examination (DRE) screening or usual care. After 7 years of follow-up, no significant difference was found in prostate cancer deaths or all-cause mortality in the screening group vs the control group. It is important to note, however, that 52% of the men in the control group had ≥1 PSA screening during the study period, which decreased the researchers’ ability to fully assess the benefits of screening.⁸

PSA’s limitations and potential harmful effects
The PSA test’s significant limitations and potentially harmful effects counter the potential benefits of screening. About 75% of positive tests are false positives, which are associated with psychological harm in some men for up to a year after the test.⁶ In addition, diagnostic testing and treatment for what may be nonlife-threatening prostate cancer can cause harm, including erectile dysfunction (ED), urinary incontinence, bowel dysfunction, and death. Rates of ED and incontinence 18 months after radical prostatectomy are an estimated 59.9% and 8.4%, respectively.⁹

Do the benefits of PSA testing outweigh the harms—and for which men? The meta-analysis and post hoc analysis detailed in this PURL help clear up the controversy.

STUDY SUMMARY: Widespread screening doesn’t save lives

Djulbegovic et al examined 6 RCTs, including the ERSPC and PLCO studies described earlier, that compared screening for prostate cancer (PSA with or without DRE) with no screening or usual care.¹ Together, the studies included nearly 390,000 men ages 45 to 80 years, and had 4 to 15 years of follow-up. The results showed that routine screening for prostate cancer had no statistically significant effect on all-cause mortality (relative risk [RR]=0.99; 95% confidence interval [CI], 0.97-1.01), death from prostate cancer (RR=0.88; 95% CI, 0.71-1.09), or diagnosis of stage III or IV prostate cancer (RR=0.94; 95% CI, 0.85-1.04). Routine screening did, however, increase the probability of being diagnosed with prostate cancer at any stage, especially at stage I. For every 1000 men screened, on average, 20 more cases of prostate cancer were diagnosed.

Healthy men may benefit from screening
Crawford et al conducted a post hoc analysis of the PLCO trial, which had found no benefit to annual PSA testing and serial DRE compared with usual care for the general population.² Their analysis compared the mortality benefits (both prostate cancer–specific and overall) of annual PSA screening for healthy men with no or minimal comorbidities vs the mortality benefits for men with any risk factor for the 2 leading causes of death: cancer and cardiovascular disease.

Annual PSA testing yielded more diagnoses of prostate cancer in both healthy and at-risk men. Deaths from prostate cancer were infrequent in both groups, occurring in 0.22% (164/73,378) of all participants.

Men with ≥1 risk factor had similar prostate cancer–specific deaths with both yearly screening and usual care (62 vs 42 deaths, adjusted hazard ratio [AHR]=1.43; 95% CI, 0.96-2.11); their prostate cancer–specific mortality rate was 0.27% (95% CI, 0.21-0.34) and 0.19% (95% CI, 0.14-0.25), respectively.

However, healthy men younger than 75 years had fewer prostate cancer–specific deaths with annual PSA screenings (22 vs 38; AHR=0.56; 95% CI, 0.33-0.95; P=.03). Specifically, the prostate cancer mortality rate was 0.17% (95% CI, 0.11-0.25) in the group that received screening vs 0.31% (95% CI, 0.22-0.42) in the usual care group. Thus, the absolute risk reduction for prostate cancer-specific mortality in men without comorbidities who received yearly screening instead of usual care was 0.14% (0.31% vs 0.17%, P=.03), with a number needed to screen of 723 to prevent one death from prostate cancer. There was a non-significant reduction in all-cause mortality in the intervention group vs the control group (AHR=0.93; 95% CI, 0.86-1.02; P=.11).

WHAT’S NEW: At best, screening has a small benefit

These trials indicate that only a small group of men will potentially benefit from PSA screening. Prior to this meta-analysis, a Cochrane review published in 2006 had concluded that there was insufficient evidence to support or refute the routine use of mass screening for prostate can-cer.¹⁰ The meta-analysis by Djulbegovic et al, which included 4 additional trials, 2 of them large, found no benefit of PSA screening in reducing mortality from prostate cancer for the general population.¹

Annual screening does appear to provide a small reduction in prostate cancer deaths but no significant reduction in all-cause mortality in men younger than age 75 who have no risk factors for cancer or cardiovascular disease.

CAVEATS: Study limitations, some unknowns

These studies did not address whether certain groups at higher risk of developing prostate cancer, such as African American men and those with a family history of prostate cancer, would benefit from PSA screening. In addition, both of the studies detailed in this PURL had substantive weaknesses.

Methodological limitations of the studies in the meta-analysis included the lack of intention-to-treat analysis and allocation concealment, which favors finding a benefit for the screening arm, and PSA screening in the nonscreening arm, which biases the results toward not finding a screening benefit that might exist. Despite these weaknesses, this meta-analysis brings together the best available evidence of the value of screening for prostate cancer.

In addition, there was no quantitative assessment of complication rates included in the meta-analysis. None of the 6 trials collected data on the effect of screening or treatment on participants’ quality of life.

In the post hoc study showing a benefit for screening healthy men, the decrease in prostate cancer deaths was small in magnitude, did not have an impact on all-cause mortality, and was of marginal statistical significance. Although the data came from the largest multicenter study to date of prostate cancer screening, the results of a post hoc analysis of a single trial should be interpreted with caution. The study was initially designed to test the effect of screening on a general population. Whenever a study deviates from the original hypothesis to evaluate a subset of the study population, the investigators increase the risk of finding a difference where none exists. Thus, it is possible that the findings of benefit for healthy men may not truly be present.

What’s more, the risk factors identified by the authors could be interpreted as arbitrary. They included diverticulosis, which is not known to increase the likelihood of cancer or heart disease, as a risk factor. By the same token, smoking—a known risk factor for both cancer and cardiovascular disease—was not addressed. Finally, potential harms associated with false-positive tests and prostate cancer treatment were not addressed in these studies.

CHALLENGES TO IMPLEMENTATION: Old habits die hard

Clinicians have recommended PSA screening for men >50 years, and men have requested such screening, for more than 2 decades. Physicians often opt to order a PSA test rather than to take the time to explain potential harms and benefits and listen to the patient’s thoughts and feelings about the value of screening. In addition, physicians who believe the lack of benefit from screening does not apply to their patients will continue to order the PSA test. (See “The perils of PSA screening”.)

Patients may opt to continue to be screened although they have developed a risk factor for cardiovascular disease. Also, a decision not to screen directly contradicts the recommendation of the American Urological Association, which calls for annual PSA testing for asymptomatic men with a life expectancy >10 years starting at 40 years of age.¹¹

Shared decision-making
The US Preventive Services Task Force (USPSTF) provides a basis for shared decision-making between physicians and patients concerning prostate cancer screening. The USPSTF states that there is insufficient evidence to recommend for or against prostate cancer screening for the general male population younger than age 75 and recommends against screening men age 75 and older or those with a life expectancy of less than 10 years.¹²

Decisions regarding PSA screening should be shared and documented for all men between the ages of 50 and 75 years. Advise patients with risk factors that the evidence shows little value and possible harm from screening. Tell healthier men that PSA testing appears to offer a small benefit, at best.

Acknowledgement

The PURLs Surveillance System is supported in part by Grant Number UL1RR024999 from the National Center for Research Resources; the grant is a Clinical Translational Science Award to the University of Chicago. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Center for Research Resources or the National Institutes of Health.

ILLUSTRATIVE CASES

A 65-year-old obese man with high blood pressure comes in for a complete physical and asks if he should have the “blood test for cancer.” He had a normal prostate specific antigen (PSA) the last time he was tested, but that was 10 years ago. What should you tell him?

A 55-year-old man schedules a routine check-up and requests a PSA test. His last test, at age 50, was normal. The patient has no known medical problems and no family history of prostate cancer, and he exercises regularly and doesn’t smoke. How should you respond to his request for a PSA test?

Prostate cancer is the second leading cause of cancer deaths among men in the United States, after lung cancer. One in 6 American men will be diagnosed with prostate cancer; for about 3% of them, the cancer will be fatal.^3,4

Widespread testing without evidence of efficacy
The PSA test was approved by the US Food and Drug Administration (FDA) in 1986.⁵ Its potential to detect early prostate cancer in the hope of decreasing morbidity and mortality led to widespread PSA screening in the 1990s, before data on the efficacy of routine screening existed.

By 2002, only one low-quality RCT that compared screening with no screening had been published. The investigators concluded that screening resulted in lower mortality rates, but a subsequent (and superior) intention-to-treat analysis showed no mortality benefit.⁶ Two large RCTs, both published in 2009, reported conflicting results.^7,8

The European Randomized Study of Screening for Prostate Cancer (ERSPC) enrolled 182,000 men ages 50 to 74 years and randomized them to either PSA screening every 4 years or no screening. Prostate cancer-specific mortality was 20% lower for those in the screening group compared with the no-screening group; however, the absolute risk reduction was only 0.71 deaths per 1000 men.⁷

The US Prostate, Lung, Colorectal, Ovarian Cancer (PLCO) Screening Trial randomized 77,000 men ages 55 to 74 years to either annual PSA and digital rectal examination (DRE) screening or usual care. After 7 years of follow-up, no significant difference was found in prostate cancer deaths or all-cause mortality in the screening group vs the control group. It is important to note, however, that 52% of the men in the control group had ≥1 PSA screening during the study period, which decreased the researchers’ ability to fully assess the benefits of screening.⁸

PSA’s limitations and potential harmful effects
The PSA test’s significant limitations and potentially harmful effects counter the potential benefits of screening. About 75% of positive tests are false positives, which are associated with psychological harm in some men for up to a year after the test.⁶ In addition, diagnostic testing and treatment for what may be nonlife-threatening prostate cancer can cause harm, including erectile dysfunction (ED), urinary incontinence, bowel dysfunction, and death. Rates of ED and incontinence 18 months after radical prostatectomy are an estimated 59.9% and 8.4%, respectively.⁹

Do the benefits of PSA testing outweigh the harms—and for which men? The meta-analysis and post hoc analysis detailed in this PURL help clear up the controversy.

STUDY SUMMARY: Widespread screening doesn’t save lives

Djulbegovic et al examined 6 RCTs, including the ERSPC and PLCO studies described earlier, that compared screening for prostate cancer (PSA with or without DRE) with no screening or usual care.¹ Together, the studies included nearly 390,000 men ages 45 to 80 years, and had 4 to 15 years of follow-up. The results showed that routine screening for prostate cancer had no statistically significant effect on all-cause mortality (relative risk [RR]=0.99; 95% confidence interval [CI], 0.97-1.01), death from prostate cancer (RR=0.88; 95% CI, 0.71-1.09), or diagnosis of stage III or IV prostate cancer (RR=0.94; 95% CI, 0.85-1.04). Routine screening did, however, increase the probability of being diagnosed with prostate cancer at any stage, especially at stage I. For every 1000 men screened, on average, 20 more cases of prostate cancer were diagnosed.

Healthy men may benefit from screening
Crawford et al conducted a post hoc analysis of the PLCO trial, which had found no benefit to annual PSA testing and serial DRE compared with usual care for the general population.² Their analysis compared the mortality benefits (both prostate cancer–specific and overall) of annual PSA screening for healthy men with no or minimal comorbidities vs the mortality benefits for men with any risk factor for the 2 leading causes of death: cancer and cardiovascular disease.

Annual PSA testing yielded more diagnoses of prostate cancer in both healthy and at-risk men. Deaths from prostate cancer were infrequent in both groups, occurring in 0.22% (164/73,378) of all participants.

Men with ≥1 risk factor had similar prostate cancer–specific deaths with both yearly screening and usual care (62 vs 42 deaths, adjusted hazard ratio [AHR]=1.43; 95% CI, 0.96-2.11); their prostate cancer–specific mortality rate was 0.27% (95% CI, 0.21-0.34) and 0.19% (95% CI, 0.14-0.25), respectively.

However, healthy men younger than 75 years had fewer prostate cancer–specific deaths with annual PSA screenings (22 vs 38; AHR=0.56; 95% CI, 0.33-0.95; P=.03). Specifically, the prostate cancer mortality rate was 0.17% (95% CI, 0.11-0.25) in the group that received screening vs 0.31% (95% CI, 0.22-0.42) in the usual care group. Thus, the absolute risk reduction for prostate cancer-specific mortality in men without comorbidities who received yearly screening instead of usual care was 0.14% (0.31% vs 0.17%, P=.03), with a number needed to screen of 723 to prevent one death from prostate cancer. There was a non-significant reduction in all-cause mortality in the intervention group vs the control group (AHR=0.93; 95% CI, 0.86-1.02; P=.11).

WHAT’S NEW: At best, screening has a small benefit

These trials indicate that only a small group of men will potentially benefit from PSA screening. Prior to this meta-analysis, a Cochrane review published in 2006 had concluded that there was insufficient evidence to support or refute the routine use of mass screening for prostate can-cer.¹⁰ The meta-analysis by Djulbegovic et al, which included 4 additional trials, 2 of them large, found no benefit of PSA screening in reducing mortality from prostate cancer for the general population.¹

Annual screening does appear to provide a small reduction in prostate cancer deaths but no significant reduction in all-cause mortality in men younger than age 75 who have no risk factors for cancer or cardiovascular disease.

CAVEATS: Study limitations, some unknowns

These studies did not address whether certain groups at higher risk of developing prostate cancer, such as African American men and those with a family history of prostate cancer, would benefit from PSA screening. In addition, both of the studies detailed in this PURL had substantive weaknesses.

Methodological limitations of the studies in the meta-analysis included the lack of intention-to-treat analysis and allocation concealment, which favors finding a benefit for the screening arm, and PSA screening in the nonscreening arm, which biases the results toward not finding a screening benefit that might exist. Despite these weaknesses, this meta-analysis brings together the best available evidence of the value of screening for prostate cancer.

In addition, there was no quantitative assessment of complication rates included in the meta-analysis. None of the 6 trials collected data on the effect of screening or treatment on participants’ quality of life.

In the post hoc study showing a benefit for screening healthy men, the decrease in prostate cancer deaths was small in magnitude, did not have an impact on all-cause mortality, and was of marginal statistical significance. Although the data came from the largest multicenter study to date of prostate cancer screening, the results of a post hoc analysis of a single trial should be interpreted with caution. The study was initially designed to test the effect of screening on a general population. Whenever a study deviates from the original hypothesis to evaluate a subset of the study population, the investigators increase the risk of finding a difference where none exists. Thus, it is possible that the findings of benefit for healthy men may not truly be present.

What’s more, the risk factors identified by the authors could be interpreted as arbitrary. They included diverticulosis, which is not known to increase the likelihood of cancer or heart disease, as a risk factor. By the same token, smoking—a known risk factor for both cancer and cardiovascular disease—was not addressed. Finally, potential harms associated with false-positive tests and prostate cancer treatment were not addressed in these studies.

CHALLENGES TO IMPLEMENTATION: Old habits die hard

Clinicians have recommended PSA screening for men >50 years, and men have requested such screening, for more than 2 decades. Physicians often opt to order a PSA test rather than to take the time to explain potential harms and benefits and listen to the patient’s thoughts and feelings about the value of screening. In addition, physicians who believe the lack of benefit from screening does not apply to their patients will continue to order the PSA test. (See “The perils of PSA screening”.)

Patients may opt to continue to be screened although they have developed a risk factor for cardiovascular disease. Also, a decision not to screen directly contradicts the recommendation of the American Urological Association, which calls for annual PSA testing for asymptomatic men with a life expectancy >10 years starting at 40 years of age.¹¹

Shared decision-making
The US Preventive Services Task Force (USPSTF) provides a basis for shared decision-making between physicians and patients concerning prostate cancer screening. The USPSTF states that there is insufficient evidence to recommend for or against prostate cancer screening for the general male population younger than age 75 and recommends against screening men age 75 and older or those with a life expectancy of less than 10 years.¹²

Decisions regarding PSA screening should be shared and documented for all men between the ages of 50 and 75 years. Advise patients with risk factors that the evidence shows little value and possible harm from screening. Tell healthier men that PSA testing appears to offer a small benefit, at best.

Acknowledgement

The PURLs Surveillance System is supported in part by Grant Number UL1RR024999 from the National Center for Research Resources; the grant is a Clinical Translational Science Award to the University of Chicago. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Center for Research Resources or the National Institutes of Health.

ILLUSTRATIVE CASES

A 65-year-old obese man with high blood pressure comes in for a complete physical and asks if he should have the “blood test for cancer.” He had a normal prostate specific antigen (PSA) the last time he was tested, but that was 10 years ago. What should you tell him?

A 55-year-old man schedules a routine check-up and requests a PSA test. His last test, at age 50, was normal. The patient has no known medical problems and no family history of prostate cancer, and he exercises regularly and doesn’t smoke. How should you respond to his request for a PSA test?

Prostate cancer is the second leading cause of cancer deaths among men in the United States, after lung cancer. One in 6 American men will be diagnosed with prostate cancer; for about 3% of them, the cancer will be fatal.^3,4

Widespread testing without evidence of efficacy
The PSA test was approved by the US Food and Drug Administration (FDA) in 1986.⁵ Its potential to detect early prostate cancer in the hope of decreasing morbidity and mortality led to widespread PSA screening in the 1990s, before data on the efficacy of routine screening existed.

By 2002, only one low-quality RCT that compared screening with no screening had been published. The investigators concluded that screening resulted in lower mortality rates, but a subsequent (and superior) intention-to-treat analysis showed no mortality benefit.⁶ Two large RCTs, both published in 2009, reported conflicting results.^7,8

The European Randomized Study of Screening for Prostate Cancer (ERSPC) enrolled 182,000 men ages 50 to 74 years and randomized them to either PSA screening every 4 years or no screening. Prostate cancer-specific mortality was 20% lower for those in the screening group compared with the no-screening group; however, the absolute risk reduction was only 0.71 deaths per 1000 men.⁷

The US Prostate, Lung, Colorectal, Ovarian Cancer (PLCO) Screening Trial randomized 77,000 men ages 55 to 74 years to either annual PSA and digital rectal examination (DRE) screening or usual care. After 7 years of follow-up, no significant difference was found in prostate cancer deaths or all-cause mortality in the screening group vs the control group. It is important to note, however, that 52% of the men in the control group had ≥1 PSA screening during the study period, which decreased the researchers’ ability to fully assess the benefits of screening.⁸

PSA’s limitations and potential harmful effects
The PSA test’s significant limitations and potentially harmful effects counter the potential benefits of screening. About 75% of positive tests are false positives, which are associated with psychological harm in some men for up to a year after the test.⁶ In addition, diagnostic testing and treatment for what may be nonlife-threatening prostate cancer can cause harm, including erectile dysfunction (ED), urinary incontinence, bowel dysfunction, and death. Rates of ED and incontinence 18 months after radical prostatectomy are an estimated 59.9% and 8.4%, respectively.⁹

Do the benefits of PSA testing outweigh the harms—and for which men? The meta-analysis and post hoc analysis detailed in this PURL help clear up the controversy.

STUDY SUMMARY: Widespread screening doesn’t save lives

Djulbegovic et al examined 6 RCTs, including the ERSPC and PLCO studies described earlier, that compared screening for prostate cancer (PSA with or without DRE) with no screening or usual care.¹ Together, the studies included nearly 390,000 men ages 45 to 80 years, and had 4 to 15 years of follow-up. The results showed that routine screening for prostate cancer had no statistically significant effect on all-cause mortality (relative risk [RR]=0.99; 95% confidence interval [CI], 0.97-1.01), death from prostate cancer (RR=0.88; 95% CI, 0.71-1.09), or diagnosis of stage III or IV prostate cancer (RR=0.94; 95% CI, 0.85-1.04). Routine screening did, however, increase the probability of being diagnosed with prostate cancer at any stage, especially at stage I. For every 1000 men screened, on average, 20 more cases of prostate cancer were diagnosed.

Healthy men may benefit from screening
Crawford et al conducted a post hoc analysis of the PLCO trial, which had found no benefit to annual PSA testing and serial DRE compared with usual care for the general population.² Their analysis compared the mortality benefits (both prostate cancer–specific and overall) of annual PSA screening for healthy men with no or minimal comorbidities vs the mortality benefits for men with any risk factor for the 2 leading causes of death: cancer and cardiovascular disease.

Annual PSA testing yielded more diagnoses of prostate cancer in both healthy and at-risk men. Deaths from prostate cancer were infrequent in both groups, occurring in 0.22% (164/73,378) of all participants.

Men with ≥1 risk factor had similar prostate cancer–specific deaths with both yearly screening and usual care (62 vs 42 deaths, adjusted hazard ratio [AHR]=1.43; 95% CI, 0.96-2.11); their prostate cancer–specific mortality rate was 0.27% (95% CI, 0.21-0.34) and 0.19% (95% CI, 0.14-0.25), respectively.

However, healthy men younger than 75 years had fewer prostate cancer–specific deaths with annual PSA screenings (22 vs 38; AHR=0.56; 95% CI, 0.33-0.95; P=.03). Specifically, the prostate cancer mortality rate was 0.17% (95% CI, 0.11-0.25) in the group that received screening vs 0.31% (95% CI, 0.22-0.42) in the usual care group. Thus, the absolute risk reduction for prostate cancer-specific mortality in men without comorbidities who received yearly screening instead of usual care was 0.14% (0.31% vs 0.17%, P=.03), with a number needed to screen of 723 to prevent one death from prostate cancer. There was a non-significant reduction in all-cause mortality in the intervention group vs the control group (AHR=0.93; 95% CI, 0.86-1.02; P=.11).

WHAT’S NEW: At best, screening has a small benefit

These trials indicate that only a small group of men will potentially benefit from PSA screening. Prior to this meta-analysis, a Cochrane review published in 2006 had concluded that there was insufficient evidence to support or refute the routine use of mass screening for prostate can-cer.¹⁰ The meta-analysis by Djulbegovic et al, which included 4 additional trials, 2 of them large, found no benefit of PSA screening in reducing mortality from prostate cancer for the general population.¹

Annual screening does appear to provide a small reduction in prostate cancer deaths but no significant reduction in all-cause mortality in men younger than age 75 who have no risk factors for cancer or cardiovascular disease.

CAVEATS: Study limitations, some unknowns

These studies did not address whether certain groups at higher risk of developing prostate cancer, such as African American men and those with a family history of prostate cancer, would benefit from PSA screening. In addition, both of the studies detailed in this PURL had substantive weaknesses.

Methodological limitations of the studies in the meta-analysis included the lack of intention-to-treat analysis and allocation concealment, which favors finding a benefit for the screening arm, and PSA screening in the nonscreening arm, which biases the results toward not finding a screening benefit that might exist. Despite these weaknesses, this meta-analysis brings together the best available evidence of the value of screening for prostate cancer.

In addition, there was no quantitative assessment of complication rates included in the meta-analysis. None of the 6 trials collected data on the effect of screening or treatment on participants’ quality of life.

In the post hoc study showing a benefit for screening healthy men, the decrease in prostate cancer deaths was small in magnitude, did not have an impact on all-cause mortality, and was of marginal statistical significance. Although the data came from the largest multicenter study to date of prostate cancer screening, the results of a post hoc analysis of a single trial should be interpreted with caution. The study was initially designed to test the effect of screening on a general population. Whenever a study deviates from the original hypothesis to evaluate a subset of the study population, the investigators increase the risk of finding a difference where none exists. Thus, it is possible that the findings of benefit for healthy men may not truly be present.

What’s more, the risk factors identified by the authors could be interpreted as arbitrary. They included diverticulosis, which is not known to increase the likelihood of cancer or heart disease, as a risk factor. By the same token, smoking—a known risk factor for both cancer and cardiovascular disease—was not addressed. Finally, potential harms associated with false-positive tests and prostate cancer treatment were not addressed in these studies.

CHALLENGES TO IMPLEMENTATION: Old habits die hard

Clinicians have recommended PSA screening for men >50 years, and men have requested such screening, for more than 2 decades. Physicians often opt to order a PSA test rather than to take the time to explain potential harms and benefits and listen to the patient’s thoughts and feelings about the value of screening. In addition, physicians who believe the lack of benefit from screening does not apply to their patients will continue to order the PSA test. (See “The perils of PSA screening”.)

Patients may opt to continue to be screened although they have developed a risk factor for cardiovascular disease. Also, a decision not to screen directly contradicts the recommendation of the American Urological Association, which calls for annual PSA testing for asymptomatic men with a life expectancy >10 years starting at 40 years of age.¹¹

Shared decision-making
The US Preventive Services Task Force (USPSTF) provides a basis for shared decision-making between physicians and patients concerning prostate cancer screening. The USPSTF states that there is insufficient evidence to recommend for or against prostate cancer screening for the general male population younger than age 75 and recommends against screening men age 75 and older or those with a life expectancy of less than 10 years.¹²

Decisions regarding PSA screening should be shared and documented for all men between the ages of 50 and 75 years. Advise patients with risk factors that the evidence shows little value and possible harm from screening. Tell healthier men that PSA testing appears to offer a small benefit, at best.

Acknowledgement

The PURLs Surveillance System is supported in part by Grant Number UL1RR024999 from the National Center for Research Resources; the grant is a Clinical Translational Science Award to the University of Chicago. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Center for Research Resources or the National Institutes of Health.