Cap-fitted colonoscopy: a randomized, tandem colonoscopy study of adenoma miss rates

David G. Hewett, Douglas K. Rex

Failures of adenoma detection diminish the effectiveness of colonoscopy. This study investigated the impact of cap-fitted colonoscopy (CFC) on the adenoma miss rate at colonoscopy. Randomized, tandem colonoscopy study. University hospital. This study involved patients undergoing elective screening or surveillance colonoscopy. Patients were randomized to undergo cap-fitted (n = 52) or regular, high-definition (n = 48) colonoscopy before undergoing a second colonoscopy by the alternate method. During CFC, a plastic cap or hood was attached to the tip of the colonoscope, which was used to flatten haustral folds and improve mucosal exposure. The primary outcome measure was the miss rate for adenomas between patients who underwent CFC first and patients who underwent regular colonoscopy first. A total of 238 adenomas were detected in 67 patients (67%), with a combined overall miss rate of 27.7%, comprising 66 missed adenomas in 38 patients. Patients undergoing initial CFC had a significantly lower miss rate for all adenomas compared with that of patients undergoing regular colonoscopy (21% vs 33%, P = .039). Miss rates with CFC were significantly lower for adenomas of ≤5 mm (22% vs 35%; P = .037). There was no significant difference in per-patient miss rates between the initial CFC group (51%, n = 18) and the initial regular colonoscopy group (63%, n = 20, P = .36). Single-center study with two endoscopists. CFC reduces miss rates for all adenomas and specifically for small adenomas. ( NCT00577083).