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A next-generation stool DNA test for colorectal cancer (CRC) screening had higher sensitivity for all screening-relevant lesions but lower specificity than a currently available fecal immunochemical test (FIT), according to the large prospective BLUE-C study.

The multi-target assay by Exact Sciences Corporation, the makers of Cologuard, includes new biomarkers designed to increase specificity without decreasing sensitivity. It showed a sensitivity for CRC of almost 94%, with more than 43% sensitivity for advanced precancerous lesions and nearly 91% specificity for advanced neoplasia, according to the study results, which were published in The New England Journal of Medicine.

Dr. Thomas F. Imperiale, Indiana University School of Medicine in Indianapolis
Indiana University School of Medicine
Dr. Thomas F. Imperiale

Adherence to CRC screening in the United States is well below the 80% national target, and the quest continues for noninvasive screening assays that might improve screening adherence, noted lead author Thomas F. Imperiale, MD, AGAF, a professor of medicine at Indiana University School of medicine in Indianapolis, and colleagues.

“The test’s manufacturer developed a new version of its existing Cologuard FIT/DNA test because it took to heart the feedback from primary care providers and gastroenterologists about the test’s low specificity,” Dr. Imperiale said in an interview. “The goal of the new test was to improve specificity without losing, and perhaps even gaining, some sensitivity — a goal that is not easily accomplished when you’re trying to improve on a sensitivity for colorectal cancer that was already 92.3% in the current version of Cologuard.”

Compared with the earlier version of Cologuard, he added, the new generation retained sensitivity for CRC and advanced precancerous lesions or polyps while improving specificity by 30% (90.6% vs 86.6%) for advanced neoplasia — a combination of CRC and advanced precancerous lesions, he said. “This with the caveat, however, that the two versions were not compared head-to-head in this new study,” Dr. Imperiale said.

The higher specificity for advanced lesions is expected to translate to a lower false positive rate. Lowering false positive rates is crucial because that reduces the need for costly, invasive, and unnecessary colonoscopies, said Aasma Shaukat, MD, MPH, AGAF, director of outcomes research in NYU Langone Health’s division of gastroenterology and hepatology in New York City.

Aasma Shaukat, MD, MPH, AGAF, is Robert M. and Mary H. Glickman Professor of Medicine and Population Health and director of GI Outcomes Research at New York University.
New York University
Dr. Aasma Shaukat

“Many physicians felt there were too many false positives with the existing version, and that is anxiety-provoking in patients and providers,” said Dr. Shaukat, who was not involved in the study.

In her view, however, the test’s moderate improvements in detecting certain lesions does not make it demonstrably superior to its predecessor, and there is always the possibility of higher cost to consider.

While acknowledging that a higher sensitivity for all advanced precancerous lesions would have been welcome, Dr. Imperiale said the test detected 75% of the most worrisome of such lesions — “the ones containing high-grade dysplastic cells and suggesting near-term conversion to cancer. And its ability to detect other advanced lesions improved as the size of the lesions increased.”
 

 

 

Testing details

Almost 21,000 asymptomatic participants age 40 years and older undergoing screening colonoscopy were evaluated at 186 US sites during the period 2019 to 2023. Of the cohort, 98 had CRC, 2144 had advanced precancerous lesions, 6973 had nonadvanced adenomas, and 10,961 had nonneoplastic findings or negative colonoscopy.

Advanced precancerous lesions included one or more adenomas or sessile serrated lesions measuring at least 1 cm in the longest dimension, lesions with villous histologic features, and high-grade dysplasia. The new DNA test identified 92 of 98 participants with CRC and 76 of 82 participants with screening-relevant cancers. Among the findings for the new assay:

  • Sensitivity for any-stage CRC was 93.9% (95% confidence interval [CI], 87.1- 97.7)
  • Sensitivity for advanced precancerous lesions was 43.4% (95% CI, 41.3-45.6)
  • Sensitivity for high-grade dysplasia was 74.6% (95% CI, 65.6-82.3)
  • Specificity for advanced neoplasia was 90.6% (95% CI, 90.1- 91.0).
  • Specificity for nonneoplastic findings or negative colonoscopy was 92.7% (95% CI, 92.2-93.1)
  • Specificity for negative colonoscopy was 93.3 (95% CI, 92.8-93.9)
  • No adverse events occurred.

In the comparator assay, OC-AUTO FIT by Polymedco, sensitivity was 67.3% (95% CI, 57.1-76.5) for CRC, 23.3% (95% CI, 21.5-25.2) for advanced precancerous lesions, and 47.4% (95% CI, 37.9-56.9) for high-grade dysplasia. In the comparator FIT, however, specificity was better across all age groups — at 94.8% (95% CI, 94.4-95.1) for advanced neoplasia, 95.7% (95% CI, 95.3- 96.1) for nonneoplastic findings, and 96.0% (95% CI, 95.5-96.4) for negative colonoscopy.

In another article in the same issue of NEJM, Guardant Health’s cell-free DNA blood-based test had 83% sensitivity for CRC, 90% specificity for advanced neoplasia, and 13% sensitivity for advanced precancerous lesions in an average-risk population.

An age-related decrease in specificity was observed with the new Cologuard test, but that did not concern Dr. Imperiale because the same observation was made with the current version. “In fact, the next-gen version appears to have less of an age-related decrease in specificity than the current version, although, again, the two versions were not tested head-to-head,” he noted.

The effect of age-related background methylation of DNA is well known, he explained. “Clinicians and older patients in the screening age range do need to be aware of this effect on specificity before ordering or agreeing to do the test. I do not see this as a stumbling block to implementation, but it does require discussion between patient and ordering provider.”

The new version of the DNA test is expected to be available in about a year.

According to Dr. Imperiale, further research is needed to ascertain the test’s acceptability and adherence rates and to quantify its yield in population-based screening. Determining its cost-effectiveness and making it easier to use are other goals. “And most importantly, the degree of reduction in the incidence and mortality from colorectal cancer,” he said.

Cost-effectiveness and the selection of the testing interval may play roles in adherence, particularly in populations with lower rates of screening adherence than the general population, John M. Carethers, MD, AGAF, of the University of California, San Diego, noted in a related editorial.

“Adherence to screening varies according to age group, including persons in the 45- to 49-year age group who are now eligible for average-risk screening,” he wrote. “It is hoped that these newer tests will increase use and adherence and elevate the percentage of the population undergoing screening in order to reduce deaths from colorectal cancer.”

This study was sponsored by Exact Sciences Corporation, which conducted the stool testing at its laboratories.

Dr. Imperiale had no competing interests to disclose. Several study co-authors reported employment with Exact Sciences, or stock and intellectual property ownership. Dr. Shaukat disclosed consulting for Freenome. Dr. Carethers reported ties to Avantor Inc. and Geneoscopy.

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A next-generation stool DNA test for colorectal cancer (CRC) screening had higher sensitivity for all screening-relevant lesions but lower specificity than a currently available fecal immunochemical test (FIT), according to the large prospective BLUE-C study.

The multi-target assay by Exact Sciences Corporation, the makers of Cologuard, includes new biomarkers designed to increase specificity without decreasing sensitivity. It showed a sensitivity for CRC of almost 94%, with more than 43% sensitivity for advanced precancerous lesions and nearly 91% specificity for advanced neoplasia, according to the study results, which were published in The New England Journal of Medicine.

Dr. Thomas F. Imperiale, Indiana University School of Medicine in Indianapolis
Indiana University School of Medicine
Dr. Thomas F. Imperiale

Adherence to CRC screening in the United States is well below the 80% national target, and the quest continues for noninvasive screening assays that might improve screening adherence, noted lead author Thomas F. Imperiale, MD, AGAF, a professor of medicine at Indiana University School of medicine in Indianapolis, and colleagues.

“The test’s manufacturer developed a new version of its existing Cologuard FIT/DNA test because it took to heart the feedback from primary care providers and gastroenterologists about the test’s low specificity,” Dr. Imperiale said in an interview. “The goal of the new test was to improve specificity without losing, and perhaps even gaining, some sensitivity — a goal that is not easily accomplished when you’re trying to improve on a sensitivity for colorectal cancer that was already 92.3% in the current version of Cologuard.”

Compared with the earlier version of Cologuard, he added, the new generation retained sensitivity for CRC and advanced precancerous lesions or polyps while improving specificity by 30% (90.6% vs 86.6%) for advanced neoplasia — a combination of CRC and advanced precancerous lesions, he said. “This with the caveat, however, that the two versions were not compared head-to-head in this new study,” Dr. Imperiale said.

The higher specificity for advanced lesions is expected to translate to a lower false positive rate. Lowering false positive rates is crucial because that reduces the need for costly, invasive, and unnecessary colonoscopies, said Aasma Shaukat, MD, MPH, AGAF, director of outcomes research in NYU Langone Health’s division of gastroenterology and hepatology in New York City.

Aasma Shaukat, MD, MPH, AGAF, is Robert M. and Mary H. Glickman Professor of Medicine and Population Health and director of GI Outcomes Research at New York University.
New York University
Dr. Aasma Shaukat

“Many physicians felt there were too many false positives with the existing version, and that is anxiety-provoking in patients and providers,” said Dr. Shaukat, who was not involved in the study.

In her view, however, the test’s moderate improvements in detecting certain lesions does not make it demonstrably superior to its predecessor, and there is always the possibility of higher cost to consider.

While acknowledging that a higher sensitivity for all advanced precancerous lesions would have been welcome, Dr. Imperiale said the test detected 75% of the most worrisome of such lesions — “the ones containing high-grade dysplastic cells and suggesting near-term conversion to cancer. And its ability to detect other advanced lesions improved as the size of the lesions increased.”
 

 

 

Testing details

Almost 21,000 asymptomatic participants age 40 years and older undergoing screening colonoscopy were evaluated at 186 US sites during the period 2019 to 2023. Of the cohort, 98 had CRC, 2144 had advanced precancerous lesions, 6973 had nonadvanced adenomas, and 10,961 had nonneoplastic findings or negative colonoscopy.

Advanced precancerous lesions included one or more adenomas or sessile serrated lesions measuring at least 1 cm in the longest dimension, lesions with villous histologic features, and high-grade dysplasia. The new DNA test identified 92 of 98 participants with CRC and 76 of 82 participants with screening-relevant cancers. Among the findings for the new assay:

  • Sensitivity for any-stage CRC was 93.9% (95% confidence interval [CI], 87.1- 97.7)
  • Sensitivity for advanced precancerous lesions was 43.4% (95% CI, 41.3-45.6)
  • Sensitivity for high-grade dysplasia was 74.6% (95% CI, 65.6-82.3)
  • Specificity for advanced neoplasia was 90.6% (95% CI, 90.1- 91.0).
  • Specificity for nonneoplastic findings or negative colonoscopy was 92.7% (95% CI, 92.2-93.1)
  • Specificity for negative colonoscopy was 93.3 (95% CI, 92.8-93.9)
  • No adverse events occurred.

In the comparator assay, OC-AUTO FIT by Polymedco, sensitivity was 67.3% (95% CI, 57.1-76.5) for CRC, 23.3% (95% CI, 21.5-25.2) for advanced precancerous lesions, and 47.4% (95% CI, 37.9-56.9) for high-grade dysplasia. In the comparator FIT, however, specificity was better across all age groups — at 94.8% (95% CI, 94.4-95.1) for advanced neoplasia, 95.7% (95% CI, 95.3- 96.1) for nonneoplastic findings, and 96.0% (95% CI, 95.5-96.4) for negative colonoscopy.

In another article in the same issue of NEJM, Guardant Health’s cell-free DNA blood-based test had 83% sensitivity for CRC, 90% specificity for advanced neoplasia, and 13% sensitivity for advanced precancerous lesions in an average-risk population.

An age-related decrease in specificity was observed with the new Cologuard test, but that did not concern Dr. Imperiale because the same observation was made with the current version. “In fact, the next-gen version appears to have less of an age-related decrease in specificity than the current version, although, again, the two versions were not tested head-to-head,” he noted.

The effect of age-related background methylation of DNA is well known, he explained. “Clinicians and older patients in the screening age range do need to be aware of this effect on specificity before ordering or agreeing to do the test. I do not see this as a stumbling block to implementation, but it does require discussion between patient and ordering provider.”

The new version of the DNA test is expected to be available in about a year.

According to Dr. Imperiale, further research is needed to ascertain the test’s acceptability and adherence rates and to quantify its yield in population-based screening. Determining its cost-effectiveness and making it easier to use are other goals. “And most importantly, the degree of reduction in the incidence and mortality from colorectal cancer,” he said.

Cost-effectiveness and the selection of the testing interval may play roles in adherence, particularly in populations with lower rates of screening adherence than the general population, John M. Carethers, MD, AGAF, of the University of California, San Diego, noted in a related editorial.

“Adherence to screening varies according to age group, including persons in the 45- to 49-year age group who are now eligible for average-risk screening,” he wrote. “It is hoped that these newer tests will increase use and adherence and elevate the percentage of the population undergoing screening in order to reduce deaths from colorectal cancer.”

This study was sponsored by Exact Sciences Corporation, which conducted the stool testing at its laboratories.

Dr. Imperiale had no competing interests to disclose. Several study co-authors reported employment with Exact Sciences, or stock and intellectual property ownership. Dr. Shaukat disclosed consulting for Freenome. Dr. Carethers reported ties to Avantor Inc. and Geneoscopy.

A next-generation stool DNA test for colorectal cancer (CRC) screening had higher sensitivity for all screening-relevant lesions but lower specificity than a currently available fecal immunochemical test (FIT), according to the large prospective BLUE-C study.

The multi-target assay by Exact Sciences Corporation, the makers of Cologuard, includes new biomarkers designed to increase specificity without decreasing sensitivity. It showed a sensitivity for CRC of almost 94%, with more than 43% sensitivity for advanced precancerous lesions and nearly 91% specificity for advanced neoplasia, according to the study results, which were published in The New England Journal of Medicine.

Dr. Thomas F. Imperiale, Indiana University School of Medicine in Indianapolis
Indiana University School of Medicine
Dr. Thomas F. Imperiale

Adherence to CRC screening in the United States is well below the 80% national target, and the quest continues for noninvasive screening assays that might improve screening adherence, noted lead author Thomas F. Imperiale, MD, AGAF, a professor of medicine at Indiana University School of medicine in Indianapolis, and colleagues.

“The test’s manufacturer developed a new version of its existing Cologuard FIT/DNA test because it took to heart the feedback from primary care providers and gastroenterologists about the test’s low specificity,” Dr. Imperiale said in an interview. “The goal of the new test was to improve specificity without losing, and perhaps even gaining, some sensitivity — a goal that is not easily accomplished when you’re trying to improve on a sensitivity for colorectal cancer that was already 92.3% in the current version of Cologuard.”

Compared with the earlier version of Cologuard, he added, the new generation retained sensitivity for CRC and advanced precancerous lesions or polyps while improving specificity by 30% (90.6% vs 86.6%) for advanced neoplasia — a combination of CRC and advanced precancerous lesions, he said. “This with the caveat, however, that the two versions were not compared head-to-head in this new study,” Dr. Imperiale said.

The higher specificity for advanced lesions is expected to translate to a lower false positive rate. Lowering false positive rates is crucial because that reduces the need for costly, invasive, and unnecessary colonoscopies, said Aasma Shaukat, MD, MPH, AGAF, director of outcomes research in NYU Langone Health’s division of gastroenterology and hepatology in New York City.

Aasma Shaukat, MD, MPH, AGAF, is Robert M. and Mary H. Glickman Professor of Medicine and Population Health and director of GI Outcomes Research at New York University.
New York University
Dr. Aasma Shaukat

“Many physicians felt there were too many false positives with the existing version, and that is anxiety-provoking in patients and providers,” said Dr. Shaukat, who was not involved in the study.

In her view, however, the test’s moderate improvements in detecting certain lesions does not make it demonstrably superior to its predecessor, and there is always the possibility of higher cost to consider.

While acknowledging that a higher sensitivity for all advanced precancerous lesions would have been welcome, Dr. Imperiale said the test detected 75% of the most worrisome of such lesions — “the ones containing high-grade dysplastic cells and suggesting near-term conversion to cancer. And its ability to detect other advanced lesions improved as the size of the lesions increased.”
 

 

 

Testing details

Almost 21,000 asymptomatic participants age 40 years and older undergoing screening colonoscopy were evaluated at 186 US sites during the period 2019 to 2023. Of the cohort, 98 had CRC, 2144 had advanced precancerous lesions, 6973 had nonadvanced adenomas, and 10,961 had nonneoplastic findings or negative colonoscopy.

Advanced precancerous lesions included one or more adenomas or sessile serrated lesions measuring at least 1 cm in the longest dimension, lesions with villous histologic features, and high-grade dysplasia. The new DNA test identified 92 of 98 participants with CRC and 76 of 82 participants with screening-relevant cancers. Among the findings for the new assay:

  • Sensitivity for any-stage CRC was 93.9% (95% confidence interval [CI], 87.1- 97.7)
  • Sensitivity for advanced precancerous lesions was 43.4% (95% CI, 41.3-45.6)
  • Sensitivity for high-grade dysplasia was 74.6% (95% CI, 65.6-82.3)
  • Specificity for advanced neoplasia was 90.6% (95% CI, 90.1- 91.0).
  • Specificity for nonneoplastic findings or negative colonoscopy was 92.7% (95% CI, 92.2-93.1)
  • Specificity for negative colonoscopy was 93.3 (95% CI, 92.8-93.9)
  • No adverse events occurred.

In the comparator assay, OC-AUTO FIT by Polymedco, sensitivity was 67.3% (95% CI, 57.1-76.5) for CRC, 23.3% (95% CI, 21.5-25.2) for advanced precancerous lesions, and 47.4% (95% CI, 37.9-56.9) for high-grade dysplasia. In the comparator FIT, however, specificity was better across all age groups — at 94.8% (95% CI, 94.4-95.1) for advanced neoplasia, 95.7% (95% CI, 95.3- 96.1) for nonneoplastic findings, and 96.0% (95% CI, 95.5-96.4) for negative colonoscopy.

In another article in the same issue of NEJM, Guardant Health’s cell-free DNA blood-based test had 83% sensitivity for CRC, 90% specificity for advanced neoplasia, and 13% sensitivity for advanced precancerous lesions in an average-risk population.

An age-related decrease in specificity was observed with the new Cologuard test, but that did not concern Dr. Imperiale because the same observation was made with the current version. “In fact, the next-gen version appears to have less of an age-related decrease in specificity than the current version, although, again, the two versions were not tested head-to-head,” he noted.

The effect of age-related background methylation of DNA is well known, he explained. “Clinicians and older patients in the screening age range do need to be aware of this effect on specificity before ordering or agreeing to do the test. I do not see this as a stumbling block to implementation, but it does require discussion between patient and ordering provider.”

The new version of the DNA test is expected to be available in about a year.

According to Dr. Imperiale, further research is needed to ascertain the test’s acceptability and adherence rates and to quantify its yield in population-based screening. Determining its cost-effectiveness and making it easier to use are other goals. “And most importantly, the degree of reduction in the incidence and mortality from colorectal cancer,” he said.

Cost-effectiveness and the selection of the testing interval may play roles in adherence, particularly in populations with lower rates of screening adherence than the general population, John M. Carethers, MD, AGAF, of the University of California, San Diego, noted in a related editorial.

“Adherence to screening varies according to age group, including persons in the 45- to 49-year age group who are now eligible for average-risk screening,” he wrote. “It is hoped that these newer tests will increase use and adherence and elevate the percentage of the population undergoing screening in order to reduce deaths from colorectal cancer.”

This study was sponsored by Exact Sciences Corporation, which conducted the stool testing at its laboratories.

Dr. Imperiale had no competing interests to disclose. Several study co-authors reported employment with Exact Sciences, or stock and intellectual property ownership. Dr. Shaukat disclosed consulting for Freenome. Dr. Carethers reported ties to Avantor Inc. and Geneoscopy.

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