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Comment on: Meta‐analysis of the role of colonoscopy after an episode of left‐sided acute diverticulitis

Editor We read with interest the systematic review and meta-analysis by Rottier et al.1. The authors searched the literature to April 2018 for studies including patients with CT-proven colon diverticulitis and reporting rates of colorectal cancer (CRC) found at colonoscopy. They included 17 studies (3296 patients) and reported a pooled prevalence of CRC of 2⋅1 (95 per cent c.i. 1⋅5 to 3⋅1) per cent. In patients with uncomplicated diverticulitis, the prevalence of CRC was 0⋅5 (95 per cent c.i. 0⋅2 to 1⋅2) per cent. The authors concluded that ‘routine colonoscopy may be omitted in patients with uncomplicated diverticulitis if CT imaging is otherwise clear’. In the same month, we also published a systematic review and meta-analysis on the subject (CRD42017083272) and considered studies based on cancer registries2. We included 31 studies (50 445 patients) and reported a pooled prevalence of CRC of 1⋅9 (95 per cent c.i. 1⋅5 to 2⋅3) per cent. We stated that the prevalence of CRC was 1⋅3 (95 per cent c.i. 0⋅1 to 2⋅0) per cent in patients with uncomplicated diverticulitis, which is higher than the prevalence reported by Rottier et al., and 7⋅9 (95 per cent c.i. 3⋅9 to 15⋅3) per cent in patients with a complicated episode. Moreover, Soh et al.3 recently reported a prevalence of CRC of 1⋅8 per cent in 227 patients with uncomplicated diverticulitis and recommended to continue performing endoscopy to exclude colorectal cancer. Further, Daniels et al.4 described that 401 patients with uncomplicated diverticulitis had higher prevalence of CRC (1⋅2 per cent, adjusted odds ratio 1⋅30, 95 per cent c.i. 0⋅39 to 4⋅36) than 1426 patients from a CRC colonoscopy screening programme (0⋅6 per cent), but this difference did not reach significance. In a retrospective cohort study with comparison to a reference population, we reported a prevalence of CRC which was 40-fold (standardized incidence ratio, 95 per cent c.i. 18⋅58 to 75⋅96) higher in patients with uncomplicated diverticulitis than in an ageand gender-matched population5. To conclude, we believe that patients with uncomplicated diverticulitis should undergo endoscopy to rule out CRC6.