Is early colonoscopy after CT-diagnosed diverticulitis still necessary?

WHO GLOBOCAN 2012 data showed that Australia and New Zealand have the highest incidence rates of colorectal cancer in the world (Ferlay et al. 1). Current guidelines recommend that patients admitted for an episode of acute diverticulitis require an early follow-up colonoscopy to rule out colorectal malignancy as reported by Fozard et al. (Colorectal Dis 13:1-11, 2011). Recent studies however have indicated that this may not be warranted (Brar et al. Dis Colon rectum 56:1259-1264, 2013). This study aimed to review the current practice by looking at our institution's rate of colorectal malignancy diagnosed after an episode of acute diverticulitis.

We conducted a retrospective analysis of patients who presented with acute diverticulitis at our institution between 2011 and 2013. Included in the study were patients who received follow-up colonic evaluation in the next 12 months after admission. Patients who had a colonoscopy in the last year prior to emergency presentation were excluded. The primary outcome measure was the incidence of histologically confirmed colorectal carcinoma diagnosed on follow-up colonoscopy. Secondary outcome measures were incidence of low-grade or advanced adenoma on follow-up colonic evaluation.

A total of 523 cases of acute diverticulitis were diagnosed on CT scan. Out of 351 patients with uncomplicated diverticulitis, 196 had follow-up colonoscopy, with one case of colorectal malignancy recorded. Low-grade and advanced adenomas were found on 10.7 and 2.0% of colonoscopies performed respectively in this subgroup. Seventy-four out of 172 patients with complicated diverticulitis had follow-up evaluation, with four cases of colorectal malignancy discovered. Low-grade and advanced adenomas were found on 6.75 and 5.41% of colonoscopies performed respectively in this subgroup.

Routine interval colonoscopy following an episode of conservatively managed uncomplicated diverticulitis may not be necessary. Interval colonoscopy is still indicated in patients with complicated diverticulitis. Further collaborative study across different institutions may be warranted to gain better statistical significance.