Reasons for Nonparticipation in a Colorectal Cancer Screening Trial Comparing Outcomes With Colonoscopy vs FIT

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In an analysis reported in JAMA Network Open, Robertson et al found U.S. veterans most frequently cited a preference for stool testing as a reason for declining participation in the CONFIRM trial, which compared the effect on colorectal cancer mortality with annual colonoscopy vs annual fecal immunochemical test (FIT).

Study Details

The CONFIRM trial aimed to assess colorectal cancer mortality among a target population of 50,000 veterans randomly assigned to undergo annual colonoscopy vs FIT. The current cross-sectional study within CONFIRM included 50,126 participants from 46 Veterans Affairs medical centers enrolled between May 2012 and December 2017; patients were aged 50 to 75 years, were at average risk for colorectal cancer, and were due for colorectal cancer screening.

Key Findings

Among a total of 50,126 recruited participants, 11,109 eligible individuals declined to participate in the trial (18.0%). Of the 11,109 who declined, 4,824 (43.4%) declined participation due to a stated preference for a specific screening test; fecal occult blood test [FOBT]/FIT was the most preferred method (2,820 [58.5%]) vs colonoscopy (1,958 [40.6%], P < .001) or other screening tests (46 [1.0%], P < .001). 

By region, preference for FOBT/FIT as a reason for declining participation was strongest in the West (963 [65.4%] of 1,472), followed by the Midwest (884 [57.3%] of 1,543), the South (774 [55.6%] of 1,392), and the Northeast (199 [53.6%] of 371; overall P = .001). In analysis adjusting for region, preference for FOBT/FIT as the reason for declining participation increased by 19% per recruitment year (odds ratio = 1.19, 95% confidence interval = 1.14–1.25)—from 59 (45.0%) of 131 in 2012 to 400 (65.5%) of 611 in 2017.

The investigators concluded, “In this cross-sectional analysis of veterans choosing nonenrollment in the CONFIRM study, those who declined participation more often preferred FOBT or FIT over colonoscopy. This preference increased over time and was strongest in the western United States and may provide insight into trends in colorectal cancer screening preferences.”

Douglas J. Robertson, MD, MPH, of the Section of Gastroenterology, VA Medical Center, White River Junction, Vermont, is the corresponding author for the JAMA Network Open article.

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