S169 Prevalence of Colon Cancer in Patients Undergoing Colonoscopy With a Diverticulitis Indication Compared to a Screening Population

Introduction: Colonoscopy is recommended for patients with acute diverticulitis to exclude colon cancer. The risk of misdiagnosis is based on limited evidence. We aimed to estimate the prevalence and relative risk of adenocarcinoma and advanced neoplasia on colonoscopy in patients with a diverticulitis indication compared to screening using information from a large colonoscopy database. Methods: GIQuIC is a US endoscopy registry that collects colonoscopy data from hundreds of ambulatory surgical centers, teaching and nonteaching hospitals, and physician offices. We included patients ³40 years with an outpatient colonoscopy report for an indication of diverticulitis or average risk screening between January 1, 2012 and December 31, 2021. The primary outcome was prevalence of adenocarcinoma on colonoscopy. The secondary outcome was advanced neoplasia (advanced adenoma, advanced serrated lesion, adenocarcinoma). Covariates included age, sex, race/ethnicity, ASA class, cecal photo, bowel preparation, and endoscopist ADR. To estimate the association between diverticulitis indication and the outcomes defined above, we used logistic regression to estimate odds ratios (ORs) and 95% confidence intervals (CIs). Models were adjusted for confounding variables. Results: We identified 91,993 colonoscopies with a diverticulitis indication and 4,591,921 screening colonoscopies. Among screening, adenocarcinoma prevalence was 0.33% and advanced neoplasia 6.9%. Among all diverticulitis, adenocarcinoma prevalence was 0.31% and advanced neoplasia 5.2%. Compared with screening, patients with diverticulitis were less likely to have adenocarcinoma (aOR 0.84, 95% CI 0.74-0.94). Among indications of follow-up for diverticulitis-only, adenocarcinoma prevalence was 0.17% and advanced neoplasia 4.3%. Compared with screening, patients with follow-up diverticulitis-only were less likely to have adenocarcinoma (aOR 0.49, 95% CI 0.36-0.68). Among diverticulitis complicated by abscess or perforation, adenocarcinoma prevalence was 1.43% and advanced neoplasia 8.1%. Compared with screening, patients with complicated diverticulitis were more likely to have adenocarcinoma (aOR 3.57, 95% CI 1.59-8.01). Conclusion: Though higher in patients with complicated diverticulitis, the prevalence of colon cancer and advanced neoplasia were lower among all patients with diverticulitis compared to the screening population. Our work suggests that follow up colonoscopy be restricted to complicated diverticulitis.