Abstract
INTRODUCTION: Colorectal cancer (CRC) is a leading cause of global cancer-related morbidity and mortality. This study examines the impact of first-time screening colonoscopy on CRC incidence in obese individuals aged 75 and older using a large US retrospective cohort. METHODS: Obese adults aged ≥ 75 were divided into two groups: those undergoing their first screening colonoscopy after 75 (Cases) and those without prior colonoscopy (Controls), using TrinetX database data. RESULTS: Propensity-matched cohorts of 123,930 patients each showed reduced CRC incidence (0.08% vs. 0.52%; OR: 0.157, p < 0.001) and lower all-cause mortality (9.6% vs. 17.3%; OR: 0.510, p < 0.001) in the colonoscopy group. The number needed to treat to prevent one CRC case was 227. Perforation rates were similar (0.2%, p = NS), but gastrointestinal bleeding was higher (5.2% vs. 4.4%; OR: 1.187, p < 0.001). CONCLUSION: Screening colonoscopy after age 75 significantly reduces CRC incidence and mortality, with manageable complication rates.