Yield of colonoscopy after recent CT-proven uncomplicated acute diverticulitis: a comparative cohort study

Current guidelines recommend routine follow-up colonoscopy after acute diverticulitis to confirm the diagnosis and exclude malignancy. Its value, however, has recently been questioned because of contradictory study results. Our objective was to compare the colonoscopic detection rate of advanced colonic neoplasia (ACN), comprising colorectal cancer (CRC) and advanced adenoma (AA), in patients after a CT-proven primary episode of uncomplicated acute diverticulitis with average risk participants in a primary colonoscopy CRC screening program. A retrospective comparison was performed of prospectively collected data from cohorts derived from two multicenter randomized clinical trials executed in the Netherlands between 2009 and 2013. 401 uncomplicated diverticulitis patients and 1,426 CRC screening participants underwent colonic evaluation by colonoscopy. Main outcome was the diagnostic yield for ACN, calculated as number of diverticulitis patients and screening participants with ACN relative to their totals, with differences expressed as odds ratios (OR). The histopathology outcome of removed lesions during colonoscopy was used as definitive diagnosis. AA detection was similar [5.5 vs. 8.7 %; OR 0.62 (95 % CI 0.38-1.01); P = 0.053]. CRC was detected in 1.2 % (5/401) of diverticulitis patients versus 0.6 % (9/1,426) of screening participants [OR 1.30 (95 % CI 0.39-4.36); P = 0.673]. ACN was diagnosed in 6.7 % (27/401) of diverticulitis patients versus 9.1 % (130/1,426) of screening participants [OR 0.71 (95 % CI 0.45-1.11); P = 0.134]. ORs were adjusted for age, family history of CRC, smoking, BMI, and cecal intubation rate. ACN detection does not differ significantly between patients with recent uncomplicated diverticulitis and average risk screening participants. Routine follow-up colonoscopy after primary CT-proven uncomplicated left-sided acute diverticulitis can be omitted; these patients can participate in CRC screening programs. Follow-up colonoscopy may be beneficial when targeted at high-risk patients, but such an approach first needs prospective evaluation.