Comparative Effectiveness of Surveillance Colonoscopy Intervals on Colorectal Cancer Outcomes in a National Cohort of Patients with Inflammatory Bowel Disease

BACKGROUND & AIMS: Surveillance colonoscopy is recommended to reduce colorectal cancer (CRC)-related morbidity and mortality in patients with inflammatory bowel disease (IBD). The comparative effectiveness of varying colonoscopy intervals on CRC outcomes among patients with IBD is unknown. METHODS: We performed a retrospective cohort study of patients with confirmed CRC within a cohort of 77,824 patients with IBD during 2000 to 2015 in the National Veterans Health Administration. We examined the association between colonoscopy surveillance intervals on CRC stage, treatment, or all-cause and cancer-specific mortality. The interval of colonoscopy prior to CRC diagnosis was categorized as those performed within <1 year, 1 to 3 years, 3 to 5 years, or none within 5 years. RESULTS: Among 566 patients with CRC-IBD, most (69.4%) did not have colonoscopy within 5 years prior to CRC diagnosis, whereas 9.7% had colonoscopy within 1 year prior to diagnosis, 17.7% within 1 to 3 years, and 3.1% between 3 and 5 years. Compared with no surveillance, colonoscopy within 1 year (adjusted odds ratio, 0.40; 95% confidence interval [CI], 0.20-0.82), and 1 to 3 years (adjusted odds ratio, 0.56; 95% CI, 0.32-0.98) were less likely to be diagnosed at late stage. Regardless of IBD type and duration, colonoscopy within 1 year was associated with a lower all-cause mortality (adjusted hazard ratio, 0.56; 95% CI, 0.36-0.88). CONCLUSIONS: In a national cohort of patients with CRC-IBD, colonoscopy within 3 years prior to CRC diagnosis was associated with early tumor stage at diagnosis, and colonoscopy within 1 year was associated with a reduced all-cause mortality compared with no colonoscopy. Our findings support colonoscopy intervals of 1 to 3 years in patients with IBD to reduce late-stage CRC and all-cause mortality.