Prevalence of colorectal cancer in acute uncomplicated diverticulitis and the role of the interval colonoscopy.

purposeAlthough computed tomography (CT) is the imaging modality of choice for diagnosing colonic diverticulitis today, there remains a risk of colorectal cancer mimicking diverticulitis due to overlapping imaging features. Current practice guidelines recommend interval colonoscopy after diverticulitis to exclude occult malignancy. Some authors have suggested that this may be unnecessary in patients with uncomplicated diverticulitis. The aim of our study was to examine the prevalence of occult colorectal cancer in patients with CT-proven acute uncomplicated diverticulitis in an Asian population.

methodsThis was a retrospective study of all patients admitted for CT-proven acute uncomplicated diverticulitis between 2007 and 2011 in a single institution. Colonoscopy and histopathology reports were reviewed for patients who underwent interval colonic evaluation. For patients who defaulted follow-up, national health records were reviewed for any subsequent diagnoses of colorectal cancer. The primary outcome was prevalence of colorectal cancer in the cohort. Secondary outcome was prevalence of advanced adenomas.

resultsA total of 227 patients with acute uncomplicated diverticulitis were included in our study. One hundred and thirty-five patients (59.5%) underwent follow-up colonic evaluation. The overall prevalence of colorectal cancer was 1.8%, with half these patients presenting with acute colonic obstruction after defaulting follow-up evaluation. Of the patients, 1.5% who underwent colonoscopy had advanced adenomas.

conclusionPrevalence of colorectal cancer in patients with CT-proven acute uncomplicated diverticulitis may not be as low as previously suggested. We recommend that patients with acute uncomplicated diverticulitis continue to be offered interval colonoscopy until larger studies demonstrate the safety of omission.