Risk of Colorectal Cancer and Advanced Polyps One Year After Excision of High-Risk Adenomas

BACKGROUND: Patients with multiple or large adenomas are considered to be high-risk for metachronous colorectal cancer. OBJECTIVE: Evaluate the risks of detecting colorectal cancer, advanced adenoma, and advanced serrated polyps at 1-year surveillance colonoscopy in patients with >5 adenomas or adenomas >20 mm. DESIGN: Descriptive, retrospective, multicentric, cohort study. We calculated the absolute risk of developing colorectal cancer, advanced adenomas, and advanced serrated polyps at the 1-year surveillance colonoscopy. Potential risk factors for advanced neoplasia at follow-up were evaluated with univariable and multivariable logistic regression analyses. SETTINGS: This study included data from a multicenter cohort colorectal cancer screening program, conducted from January 2014 to December 2015, based on fecal immunochemical tests in Spain. PATIENTS: We included 2119 participants with at least 1 adenoma >= 20 mm or >= 5 adenomas of any size. MAIN OUTCOME MEASURES: We calculated the absolute risk of developing colorectal cancer, advanced adenomas, and advanced serrated polyps at the 1-year surveillance colonoscopy. Potential risk factors for advanced neoplasia at follow-up were evaluated with univariable and multivariable logistic regression analyses. RESULTS: At 1 year, participants displayed 6 colorectal cancers (0.3%), 228 advanced adenomas (10.5%), and 58 advanced serrated polyps (2.7%). The adjusted analysis identified 2 factors associated with advanced neoplasia: >5 adenomas (odds ratio 1.53; 95% CI: 1.15-2.03; p = 0.004) and polyps in a proximal location (OR 1.52; 95% CI: 1.15-2.02; p = 0.004). LIMITATIONS: First, the sample size was relatively small compared to other studies with similar aims. Another limitation was the lack of a comparison group, which could have provided more practical results in terms of surveillance recommendations. CONCLUSIONS: The colorectal cancer detection rate at a 1-year colonoscopy surveillance was low among patients classified at high risk of advanced neoplasia. The risk factors for advanced neoplasia were adenomas and proximal polyps at baseline. See Video Abstract at http:// links.lww.com/DCR/B820.