Long-Term Colorectal Cancer Incidence After Adenoma and Serrated Polyp Removal: Results From the Colonprev Trial

Abstract

BACKGROUND: The risk of colorectal cancer (CRC) after serrated polyp resection remains unclear, and current surveillance recommendations rely on limited evidence. We evaluated CRC incidence in individuals with advanced serrated lesions (ASL) detected at baseline colonoscopy and compared risk according to the most advanced lesion identified. METHODS: Participants undergoing colonoscopy within the COLONPREV trial (n = 8989) were included in this post hoc analysis. Individuals were classified according to the most advanced baseline lesion: no lesion, non-advanced adenoma, advanced adenoma, or ASL. The primary outcome was incident CRC. Cumulative incidence and hazard ratios (HR) were estimated using Cox proportional hazard models. RESULTS: At baseline colonoscopy, serrated polyps were detected in 19.8% of participants, including ASL in 2.5%. Over a mean follow-up of 9.5 years, 44 CRC cases were diagnosed (cumulative incidence 0.49%; incidence rate 0.52 per 1000 person-years). The 10-year cumulative incidence was 0.27% in individuals without baseline lesions (n = 5496), 0.57% in those with non-advanced adenomas (n = 2091), 1.23% in advanced adenomas (n = 1218), and 1.09% in ASL (n = 184). In multivariable analysis, CRC risk was increased for non-advanced adenomas (HR 3.25, 95% CI 1.48-7.16), advanced adenomas (HR 9.77, 95% CI 4.24-22.50), and ASL (HR 6.37, 95% CI 1.42-28.54). Surveillance colonoscopy was associated with lower CRC incidence (HR 0.46, 95% CI 0.22-0.95 for one colonoscopy; HR 0.09, 95% CI 0.02-0.40 for ? 2 colonoscopies). CONCLUSION: In this screening cohort, ASL were associated with increased CRC risk in the range of advanced adenomas. These findings provide risk estimates relevant to post-polypectomy management. TRIAL REGISTRATION NUMBER: NCT00906997.