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Study 1 Overview (Bretthauer et al)
Objective: To evaluate the impact of screening colonoscopy on colon cancer–related death.
Design: Randomized trial conducted in 4 European countries.
Setting and participants: Presumptively healthy men and women between the ages of 55 and 64 years were selected from population registries in Poland, Norway, Sweden, and the Netherlands between 2009 and 2014. Eligible participants had not previously undergone screening. Patients with a diagnosis of colon cancer before trial entry were excluded.
Intervention: Participants were randomly assigned in a 1:2 ratio to undergo colonoscopy screening by invitation or to no invitation and no screening. Participants were randomized using a computer-generated allocation algorithm. Patients were stratified by age, sex, and municipality.
Main outcome measures: The primary endpoint of the study was risk of colorectal cancer and related death after a median follow-up of 10 to 15 years. The main secondary endpoint was death from any cause.
Main results: The study reported follow-up data from 84,585 participants (89.1% of all participants originally included in the trial). The remaining participants were either excluded or data could not be included due to lack of follow-up data from the usual-care group. Men (50.1%) and women (49.9%) were equally represented. The median age at entry was 59 years. The median follow-up was 10 years. Characteristics were otherwise balanced. Good bowel preparation was reported in 91% of all participants. Cecal intubation was achieved in 96.8% of all participants. The percentage of patients who underwent screening was 42% for the group, but screening rates varied by country (33%-60%). Colorectal cancer was diagnosed at screening in 62 participants (0.5% of screening group). Adenomas were detected in 30.7% of participants; 15 patients had polypectomy-related major bleeding. There were no perforations.
The risk of colorectal cancer at 10 years was 0.98% in the invited-to-screen group and 1.2% in the usual-care group (risk ratio, 0.82; 95% CI, 0.7-0.93). The reported number needed to invite to prevent 1 case of colon cancer in a 10-year period was 455. The risk of colorectal cancer–related death at 10 years was 0.28% in the invited-to-screen group and 0.31% in the usual-care group (risk ratio, 0.9; 95% CI, 0.64-1.16). An adjusted per-protocol analysis was performed to account for the estimated effect of screening if all participants assigned to the screening group underwent screening. In this analysis, the risk of colorectal cancer at 10 years was decreased from 1.22% to 0.84% (risk ratio, 0.69; 95% CI, 0.66-0.83).
Conclusion: Based on the results of this European randomized trial, the risk of colorectal cancer at 10 years was lower among those who were invited to undergo screening.
Study 2 Overview (Forsberg et al)
Objective: To investigate the effect of colorectal cancer screening with once-only colonoscopy or fecal immunochemical testing (FIT) on colorectal cancer mortality and incidence.
Design: Randomized controlled trial in Sweden utilizing a population registry.
Setting and participants: Patients aged 60 years at the time of entry were identified from a population-based registry from the Swedish Tax Agency.
Intervention: Individuals were assigned by an independent statistician to once-only colonoscopy, 2 rounds of FIT 2 years apart, or a control group in which no intervention was performed. Patients were assigned in a 1:6 ratio for colonoscopy vs control and a 1:2 ratio for FIT vs control.
Main outcome measures: The primary endpoint of the trial was colorectal cancer incidence and mortality.
Main results: A total of 278,280 participants were included in the study from March 1, 2014, through December 31, 2020 (31,140 in the colonoscopy group, 60,300 in the FIT group, and 186,840 in the control group). Of those in the colonoscopy group, 35% underwent colonoscopy, and 55% of those in the FIT group participated in testing. Colorectal cancer was detected in 0.16% (49) of people in the colonoscopy group and 0.2% (121) of people in the FIT test group (relative risk, 0.78; 95% CI, 0.56-1.09). The advanced adenoma detection rate was 2.05% in the colonoscopy group and 1.61% in the FIT group (relative risk, 1.27; 95% CI, 1.15-1.41). There were 2 perforations noted in the colonoscopy group and 15 major bleeding events. More right-sided adenomas were detected in the colonoscopy group.
Conclusion: The results of the current study highlight similar detection rates in the colonoscopy and FIT group. Should further follow-up show a benefit in disease-specific mortality, such screening strategies could be translated into population-based screening programs.
Commentary
The first colonoscopy screening recommendations were established in the mid 1990s in the United States, and over the subsequent 2 decades colonoscopy has been the recommended method and main modality for colorectal cancer screening in this country. The advantage of colonoscopy over other screening modalities (sigmoidoscopy and fecal-based testing) is that it can examine the entire large bowel and allow for removal of potential precancerous lesions. However, data to support colonoscopy as a screening modality for colorectal cancer are largely based on cohort studies.1,2 These studies have reported a significant reduction in the incidence of colon cancer. Additionally, colorectal cancer mortality was notably lower in the screened populations. For example, one study among health professionals found a nearly 70% reduction in colorectal cancer mortality in those who underwent at least 1 screening colonoscopy.3
There has been a lack of randomized clinical data to validate the efficacy of colonoscopy screening for reducing colorectal cancer–related deaths. The current study by Bretthauer et al addresses an important need and enhances our understanding of the efficacy of colorectal cancer screening with colonoscopy. In this randomized trial involving more than 84,000 participants from Poland, Norway, Sweden, and the Netherlands, there was a noted 18% decrease in the risk of colorectal cancer over a 10-year period in the intention-to-screen population. The reduction in the risk of death from colorectal cancer was not statistically significant (risk ratio, 0.90; 95% CI, 0.64-1.16). These results are surprising and certainly raise the question as to whether previous studies overestimated the effectiveness of colonoscopy in reducing the risk of colorectal cancer–related deaths. There are several limitations to the Bretthauer et al study, however.
Perhaps the most important limitation is the fact that only 42% of participants in the invited-to-screen cohort underwent screening colonoscopy. Therefore, this raises the question of whether the efficacy noted is simply due to a lack of participation in the screening protocol. In the adjusted per-protocol analysis, colonoscopy was estimated to reduce the risk of colorectal cancer by 31% and the risk of colorectal cancer–related death by around 50%. These findings are more in line with prior published studies regarding the efficacy of colorectal cancer screening. The authors plan to repeat this analysis at 15 years, and it is possible that the risk of colorectal cancer and colorectal cancer–related death can be reduced on subsequent follow-up.
While the results of the Bretthauer et al trial are important, randomized trials that directly compare the effectiveness of different colorectal cancer screening strategies are lacking. The Forsberg et al trial, also an ongoing study, seeks to address this vitally important gap in our current data. The SCREESCO trial is a study that compares the efficacy of colonoscopy with FIT every 2 years or no screening. The currently reported data are preliminary but show a similarly low rate of colonoscopy screening in those invited to do so (35%). This is a similar limitation to that noted in the Bretthauer et al study. Furthermore, there is some question regarding colonoscopy quality in this study, which had a very low reported adenoma detection rate.
While the current studies are important and provide quality randomized data on the effect of colorectal cancer screening, there remain many unanswered questions. Should the results presented by Bretthauer et al represent the current real-world scenario, then colonoscopy screening may not be viewed as an effective screening tool compared to simpler, less-invasive modalities (ie, FIT). Further follow-up from the SCREESCO trial will help shed light on this question. However, there are concerns with this study, including a very low participation rate, which could greatly underestimate the effectiveness of screening. Additional analysis and longer follow-up will be vital to fully understand the benefits of screening colonoscopy. In the meantime, screening remains an important tool for early detection of colorectal cancer and remains a category A recommendation by the United States Preventive Services Task Force.4
Applications for Clinical Practice and System Implementation
Current guidelines continue to strongly recommend screening for colorectal cancer for persons between 45 and 75 years of age (category B recommendation for those aged 45 to 49 years per the United States Preventive Services Task Force). Stool-based tests and direct visualization tests are both endorsed as screening options. Further follow-up from the presented studies is needed to help shed light on the magnitude of benefit of these modalities.
Practice Points
- Current guidelines continue to strongly recommend screening for colon cancer in those aged 45 to 75 years.
- The optimal modality for screening and the impact of screening on cancer-related mortality requires longer- term follow-up from these ongoing studies.
–Daniel Isaac, DO, MS
1. Lin JS, Perdue LA, Henrikson NB, Bean SI, Blasi PR. Screening for Colorectal Cancer: An Evidence Update for the U.S. Preventive Services Task Force [Internet]. Rockville (MD): Agency for Healthcare Research and Quality (US); 2021 May. Report No.: 20-05271-EF-1.
2. Lin JS, Perdue LA, Henrikson NB, Bean SI, Blasi PR. Screening for colorectal cancer: updated evidence report and systematic review for the US Preventive Services Task Force. JAMA. 2021;325(19):1978-1998. doi:10.1001/jama.2021.4417
3. Nishihara R, Wu K, Lochhead P, et al. Long-term colorectal-cancer incidence and mortality after lower endoscopy. N Engl J Med. 2013;369(12):1095-1105. doi:10.1056/NEJMoa1301969
4. U.S. Preventive Services Task Force. Colorectal cancer: screening. Published May 18, 2021. Accessed November 8, 2022. https://uspreventiveservicestaskforce.org/uspstf/recommendation/colorectal-cancer-screening
Study 1 Overview (Bretthauer et al)
Objective: To evaluate the impact of screening colonoscopy on colon cancer–related death.
Design: Randomized trial conducted in 4 European countries.
Setting and participants: Presumptively healthy men and women between the ages of 55 and 64 years were selected from population registries in Poland, Norway, Sweden, and the Netherlands between 2009 and 2014. Eligible participants had not previously undergone screening. Patients with a diagnosis of colon cancer before trial entry were excluded.
Intervention: Participants were randomly assigned in a 1:2 ratio to undergo colonoscopy screening by invitation or to no invitation and no screening. Participants were randomized using a computer-generated allocation algorithm. Patients were stratified by age, sex, and municipality.
Main outcome measures: The primary endpoint of the study was risk of colorectal cancer and related death after a median follow-up of 10 to 15 years. The main secondary endpoint was death from any cause.
Main results: The study reported follow-up data from 84,585 participants (89.1% of all participants originally included in the trial). The remaining participants were either excluded or data could not be included due to lack of follow-up data from the usual-care group. Men (50.1%) and women (49.9%) were equally represented. The median age at entry was 59 years. The median follow-up was 10 years. Characteristics were otherwise balanced. Good bowel preparation was reported in 91% of all participants. Cecal intubation was achieved in 96.8% of all participants. The percentage of patients who underwent screening was 42% for the group, but screening rates varied by country (33%-60%). Colorectal cancer was diagnosed at screening in 62 participants (0.5% of screening group). Adenomas were detected in 30.7% of participants; 15 patients had polypectomy-related major bleeding. There were no perforations.
The risk of colorectal cancer at 10 years was 0.98% in the invited-to-screen group and 1.2% in the usual-care group (risk ratio, 0.82; 95% CI, 0.7-0.93). The reported number needed to invite to prevent 1 case of colon cancer in a 10-year period was 455. The risk of colorectal cancer–related death at 10 years was 0.28% in the invited-to-screen group and 0.31% in the usual-care group (risk ratio, 0.9; 95% CI, 0.64-1.16). An adjusted per-protocol analysis was performed to account for the estimated effect of screening if all participants assigned to the screening group underwent screening. In this analysis, the risk of colorectal cancer at 10 years was decreased from 1.22% to 0.84% (risk ratio, 0.69; 95% CI, 0.66-0.83).
Conclusion: Based on the results of this European randomized trial, the risk of colorectal cancer at 10 years was lower among those who were invited to undergo screening.
Study 2 Overview (Forsberg et al)
Objective: To investigate the effect of colorectal cancer screening with once-only colonoscopy or fecal immunochemical testing (FIT) on colorectal cancer mortality and incidence.
Design: Randomized controlled trial in Sweden utilizing a population registry.
Setting and participants: Patients aged 60 years at the time of entry were identified from a population-based registry from the Swedish Tax Agency.
Intervention: Individuals were assigned by an independent statistician to once-only colonoscopy, 2 rounds of FIT 2 years apart, or a control group in which no intervention was performed. Patients were assigned in a 1:6 ratio for colonoscopy vs control and a 1:2 ratio for FIT vs control.
Main outcome measures: The primary endpoint of the trial was colorectal cancer incidence and mortality.
Main results: A total of 278,280 participants were included in the study from March 1, 2014, through December 31, 2020 (31,140 in the colonoscopy group, 60,300 in the FIT group, and 186,840 in the control group). Of those in the colonoscopy group, 35% underwent colonoscopy, and 55% of those in the FIT group participated in testing. Colorectal cancer was detected in 0.16% (49) of people in the colonoscopy group and 0.2% (121) of people in the FIT test group (relative risk, 0.78; 95% CI, 0.56-1.09). The advanced adenoma detection rate was 2.05% in the colonoscopy group and 1.61% in the FIT group (relative risk, 1.27; 95% CI, 1.15-1.41). There were 2 perforations noted in the colonoscopy group and 15 major bleeding events. More right-sided adenomas were detected in the colonoscopy group.
Conclusion: The results of the current study highlight similar detection rates in the colonoscopy and FIT group. Should further follow-up show a benefit in disease-specific mortality, such screening strategies could be translated into population-based screening programs.
Commentary
The first colonoscopy screening recommendations were established in the mid 1990s in the United States, and over the subsequent 2 decades colonoscopy has been the recommended method and main modality for colorectal cancer screening in this country. The advantage of colonoscopy over other screening modalities (sigmoidoscopy and fecal-based testing) is that it can examine the entire large bowel and allow for removal of potential precancerous lesions. However, data to support colonoscopy as a screening modality for colorectal cancer are largely based on cohort studies.1,2 These studies have reported a significant reduction in the incidence of colon cancer. Additionally, colorectal cancer mortality was notably lower in the screened populations. For example, one study among health professionals found a nearly 70% reduction in colorectal cancer mortality in those who underwent at least 1 screening colonoscopy.3
There has been a lack of randomized clinical data to validate the efficacy of colonoscopy screening for reducing colorectal cancer–related deaths. The current study by Bretthauer et al addresses an important need and enhances our understanding of the efficacy of colorectal cancer screening with colonoscopy. In this randomized trial involving more than 84,000 participants from Poland, Norway, Sweden, and the Netherlands, there was a noted 18% decrease in the risk of colorectal cancer over a 10-year period in the intention-to-screen population. The reduction in the risk of death from colorectal cancer was not statistically significant (risk ratio, 0.90; 95% CI, 0.64-1.16). These results are surprising and certainly raise the question as to whether previous studies overestimated the effectiveness of colonoscopy in reducing the risk of colorectal cancer–related deaths. There are several limitations to the Bretthauer et al study, however.
Perhaps the most important limitation is the fact that only 42% of participants in the invited-to-screen cohort underwent screening colonoscopy. Therefore, this raises the question of whether the efficacy noted is simply due to a lack of participation in the screening protocol. In the adjusted per-protocol analysis, colonoscopy was estimated to reduce the risk of colorectal cancer by 31% and the risk of colorectal cancer–related death by around 50%. These findings are more in line with prior published studies regarding the efficacy of colorectal cancer screening. The authors plan to repeat this analysis at 15 years, and it is possible that the risk of colorectal cancer and colorectal cancer–related death can be reduced on subsequent follow-up.
While the results of the Bretthauer et al trial are important, randomized trials that directly compare the effectiveness of different colorectal cancer screening strategies are lacking. The Forsberg et al trial, also an ongoing study, seeks to address this vitally important gap in our current data. The SCREESCO trial is a study that compares the efficacy of colonoscopy with FIT every 2 years or no screening. The currently reported data are preliminary but show a similarly low rate of colonoscopy screening in those invited to do so (35%). This is a similar limitation to that noted in the Bretthauer et al study. Furthermore, there is some question regarding colonoscopy quality in this study, which had a very low reported adenoma detection rate.
While the current studies are important and provide quality randomized data on the effect of colorectal cancer screening, there remain many unanswered questions. Should the results presented by Bretthauer et al represent the current real-world scenario, then colonoscopy screening may not be viewed as an effective screening tool compared to simpler, less-invasive modalities (ie, FIT). Further follow-up from the SCREESCO trial will help shed light on this question. However, there are concerns with this study, including a very low participation rate, which could greatly underestimate the effectiveness of screening. Additional analysis and longer follow-up will be vital to fully understand the benefits of screening colonoscopy. In the meantime, screening remains an important tool for early detection of colorectal cancer and remains a category A recommendation by the United States Preventive Services Task Force.4
Applications for Clinical Practice and System Implementation
Current guidelines continue to strongly recommend screening for colorectal cancer for persons between 45 and 75 years of age (category B recommendation for those aged 45 to 49 years per the United States Preventive Services Task Force). Stool-based tests and direct visualization tests are both endorsed as screening options. Further follow-up from the presented studies is needed to help shed light on the magnitude of benefit of these modalities.
Practice Points
- Current guidelines continue to strongly recommend screening for colon cancer in those aged 45 to 75 years.
- The optimal modality for screening and the impact of screening on cancer-related mortality requires longer- term follow-up from these ongoing studies.
–Daniel Isaac, DO, MS
Study 1 Overview (Bretthauer et al)
Objective: To evaluate the impact of screening colonoscopy on colon cancer–related death.
Design: Randomized trial conducted in 4 European countries.
Setting and participants: Presumptively healthy men and women between the ages of 55 and 64 years were selected from population registries in Poland, Norway, Sweden, and the Netherlands between 2009 and 2014. Eligible participants had not previously undergone screening. Patients with a diagnosis of colon cancer before trial entry were excluded.
Intervention: Participants were randomly assigned in a 1:2 ratio to undergo colonoscopy screening by invitation or to no invitation and no screening. Participants were randomized using a computer-generated allocation algorithm. Patients were stratified by age, sex, and municipality.
Main outcome measures: The primary endpoint of the study was risk of colorectal cancer and related death after a median follow-up of 10 to 15 years. The main secondary endpoint was death from any cause.
Main results: The study reported follow-up data from 84,585 participants (89.1% of all participants originally included in the trial). The remaining participants were either excluded or data could not be included due to lack of follow-up data from the usual-care group. Men (50.1%) and women (49.9%) were equally represented. The median age at entry was 59 years. The median follow-up was 10 years. Characteristics were otherwise balanced. Good bowel preparation was reported in 91% of all participants. Cecal intubation was achieved in 96.8% of all participants. The percentage of patients who underwent screening was 42% for the group, but screening rates varied by country (33%-60%). Colorectal cancer was diagnosed at screening in 62 participants (0.5% of screening group). Adenomas were detected in 30.7% of participants; 15 patients had polypectomy-related major bleeding. There were no perforations.
The risk of colorectal cancer at 10 years was 0.98% in the invited-to-screen group and 1.2% in the usual-care group (risk ratio, 0.82; 95% CI, 0.7-0.93). The reported number needed to invite to prevent 1 case of colon cancer in a 10-year period was 455. The risk of colorectal cancer–related death at 10 years was 0.28% in the invited-to-screen group and 0.31% in the usual-care group (risk ratio, 0.9; 95% CI, 0.64-1.16). An adjusted per-protocol analysis was performed to account for the estimated effect of screening if all participants assigned to the screening group underwent screening. In this analysis, the risk of colorectal cancer at 10 years was decreased from 1.22% to 0.84% (risk ratio, 0.69; 95% CI, 0.66-0.83).
Conclusion: Based on the results of this European randomized trial, the risk of colorectal cancer at 10 years was lower among those who were invited to undergo screening.
Study 2 Overview (Forsberg et al)
Objective: To investigate the effect of colorectal cancer screening with once-only colonoscopy or fecal immunochemical testing (FIT) on colorectal cancer mortality and incidence.
Design: Randomized controlled trial in Sweden utilizing a population registry.
Setting and participants: Patients aged 60 years at the time of entry were identified from a population-based registry from the Swedish Tax Agency.
Intervention: Individuals were assigned by an independent statistician to once-only colonoscopy, 2 rounds of FIT 2 years apart, or a control group in which no intervention was performed. Patients were assigned in a 1:6 ratio for colonoscopy vs control and a 1:2 ratio for FIT vs control.
Main outcome measures: The primary endpoint of the trial was colorectal cancer incidence and mortality.
Main results: A total of 278,280 participants were included in the study from March 1, 2014, through December 31, 2020 (31,140 in the colonoscopy group, 60,300 in the FIT group, and 186,840 in the control group). Of those in the colonoscopy group, 35% underwent colonoscopy, and 55% of those in the FIT group participated in testing. Colorectal cancer was detected in 0.16% (49) of people in the colonoscopy group and 0.2% (121) of people in the FIT test group (relative risk, 0.78; 95% CI, 0.56-1.09). The advanced adenoma detection rate was 2.05% in the colonoscopy group and 1.61% in the FIT group (relative risk, 1.27; 95% CI, 1.15-1.41). There were 2 perforations noted in the colonoscopy group and 15 major bleeding events. More right-sided adenomas were detected in the colonoscopy group.
Conclusion: The results of the current study highlight similar detection rates in the colonoscopy and FIT group. Should further follow-up show a benefit in disease-specific mortality, such screening strategies could be translated into population-based screening programs.
Commentary
The first colonoscopy screening recommendations were established in the mid 1990s in the United States, and over the subsequent 2 decades colonoscopy has been the recommended method and main modality for colorectal cancer screening in this country. The advantage of colonoscopy over other screening modalities (sigmoidoscopy and fecal-based testing) is that it can examine the entire large bowel and allow for removal of potential precancerous lesions. However, data to support colonoscopy as a screening modality for colorectal cancer are largely based on cohort studies.1,2 These studies have reported a significant reduction in the incidence of colon cancer. Additionally, colorectal cancer mortality was notably lower in the screened populations. For example, one study among health professionals found a nearly 70% reduction in colorectal cancer mortality in those who underwent at least 1 screening colonoscopy.3
There has been a lack of randomized clinical data to validate the efficacy of colonoscopy screening for reducing colorectal cancer–related deaths. The current study by Bretthauer et al addresses an important need and enhances our understanding of the efficacy of colorectal cancer screening with colonoscopy. In this randomized trial involving more than 84,000 participants from Poland, Norway, Sweden, and the Netherlands, there was a noted 18% decrease in the risk of colorectal cancer over a 10-year period in the intention-to-screen population. The reduction in the risk of death from colorectal cancer was not statistically significant (risk ratio, 0.90; 95% CI, 0.64-1.16). These results are surprising and certainly raise the question as to whether previous studies overestimated the effectiveness of colonoscopy in reducing the risk of colorectal cancer–related deaths. There are several limitations to the Bretthauer et al study, however.
Perhaps the most important limitation is the fact that only 42% of participants in the invited-to-screen cohort underwent screening colonoscopy. Therefore, this raises the question of whether the efficacy noted is simply due to a lack of participation in the screening protocol. In the adjusted per-protocol analysis, colonoscopy was estimated to reduce the risk of colorectal cancer by 31% and the risk of colorectal cancer–related death by around 50%. These findings are more in line with prior published studies regarding the efficacy of colorectal cancer screening. The authors plan to repeat this analysis at 15 years, and it is possible that the risk of colorectal cancer and colorectal cancer–related death can be reduced on subsequent follow-up.
While the results of the Bretthauer et al trial are important, randomized trials that directly compare the effectiveness of different colorectal cancer screening strategies are lacking. The Forsberg et al trial, also an ongoing study, seeks to address this vitally important gap in our current data. The SCREESCO trial is a study that compares the efficacy of colonoscopy with FIT every 2 years or no screening. The currently reported data are preliminary but show a similarly low rate of colonoscopy screening in those invited to do so (35%). This is a similar limitation to that noted in the Bretthauer et al study. Furthermore, there is some question regarding colonoscopy quality in this study, which had a very low reported adenoma detection rate.
While the current studies are important and provide quality randomized data on the effect of colorectal cancer screening, there remain many unanswered questions. Should the results presented by Bretthauer et al represent the current real-world scenario, then colonoscopy screening may not be viewed as an effective screening tool compared to simpler, less-invasive modalities (ie, FIT). Further follow-up from the SCREESCO trial will help shed light on this question. However, there are concerns with this study, including a very low participation rate, which could greatly underestimate the effectiveness of screening. Additional analysis and longer follow-up will be vital to fully understand the benefits of screening colonoscopy. In the meantime, screening remains an important tool for early detection of colorectal cancer and remains a category A recommendation by the United States Preventive Services Task Force.4
Applications for Clinical Practice and System Implementation
Current guidelines continue to strongly recommend screening for colorectal cancer for persons between 45 and 75 years of age (category B recommendation for those aged 45 to 49 years per the United States Preventive Services Task Force). Stool-based tests and direct visualization tests are both endorsed as screening options. Further follow-up from the presented studies is needed to help shed light on the magnitude of benefit of these modalities.
Practice Points
- Current guidelines continue to strongly recommend screening for colon cancer in those aged 45 to 75 years.
- The optimal modality for screening and the impact of screening on cancer-related mortality requires longer- term follow-up from these ongoing studies.
–Daniel Isaac, DO, MS
1. Lin JS, Perdue LA, Henrikson NB, Bean SI, Blasi PR. Screening for Colorectal Cancer: An Evidence Update for the U.S. Preventive Services Task Force [Internet]. Rockville (MD): Agency for Healthcare Research and Quality (US); 2021 May. Report No.: 20-05271-EF-1.
2. Lin JS, Perdue LA, Henrikson NB, Bean SI, Blasi PR. Screening for colorectal cancer: updated evidence report and systematic review for the US Preventive Services Task Force. JAMA. 2021;325(19):1978-1998. doi:10.1001/jama.2021.4417
3. Nishihara R, Wu K, Lochhead P, et al. Long-term colorectal-cancer incidence and mortality after lower endoscopy. N Engl J Med. 2013;369(12):1095-1105. doi:10.1056/NEJMoa1301969
4. U.S. Preventive Services Task Force. Colorectal cancer: screening. Published May 18, 2021. Accessed November 8, 2022. https://uspreventiveservicestaskforce.org/uspstf/recommendation/colorectal-cancer-screening
1. Lin JS, Perdue LA, Henrikson NB, Bean SI, Blasi PR. Screening for Colorectal Cancer: An Evidence Update for the U.S. Preventive Services Task Force [Internet]. Rockville (MD): Agency for Healthcare Research and Quality (US); 2021 May. Report No.: 20-05271-EF-1.
2. Lin JS, Perdue LA, Henrikson NB, Bean SI, Blasi PR. Screening for colorectal cancer: updated evidence report and systematic review for the US Preventive Services Task Force. JAMA. 2021;325(19):1978-1998. doi:10.1001/jama.2021.4417
3. Nishihara R, Wu K, Lochhead P, et al. Long-term colorectal-cancer incidence and mortality after lower endoscopy. N Engl J Med. 2013;369(12):1095-1105. doi:10.1056/NEJMoa1301969
4. U.S. Preventive Services Task Force. Colorectal cancer: screening. Published May 18, 2021. Accessed November 8, 2022. https://uspreventiveservicestaskforce.org/uspstf/recommendation/colorectal-cancer-screening