Colonoscopy versus biennial FIT screening: a post hoc sustained-strategy analysis of the COLONPREV Trial

Abstract

BACKGROUND: Pragmatic colorectal cancer (CRC) screening trials compare colonoscopy with faecal immunochemical testing (FIT), but differences in adherence complicate interpretation of comparative outcomes. OBJECTIVE: To compare 10-year risks of CRC mortality, CRC incidence and all-cause mortality under one-time colonoscopy versus sustained FIT strategies in the COLONPREV Trial. DESIGN: We conducted a post hoc per-protocol analysis of 17 270 screening initiators aged 50-69 years in eight Spanish regions, using inverse probability weighting to adjust for observed confounding and informative protocol deviations. RESULTS: Weighted 10-year risks were similar for CRC incidence (0.80% FIT vs 0.86% colonoscopy; risk difference (RD) 0.06%, 95% CI -0.25% to 0.37%) and all-cause mortality (4.02% vs 4.09%; RD 0.07%, 95% CI -0.76% to 0.84%). CRC mortality was lower with colonoscopy (0.072% FIT vs 0.042% colonoscopy; RD -0.03%, 95% CI -0.12% to 0.06%), but estimates were imprecise. CONCLUSION: Sustained colonoscopy and FIT showed similar 10-year outcomes overall, highlighting the importance of adherence pathways in pragmatic screening trials. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov: NCT00906997.