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

Background: Failures of adenoma detection diminish the effectiveness of colonoscopy.

Objective: This study investigated the impact of cap-fitted colonoscopy (CFC) on the adenoma miss rate at colonoscopy.

Design: Randomized, tandem colonoscopy study.

Setting: University hospital.

Patients: This study involved patients undergoing elective screening or surveillance colonoscopy.

Intervention: 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.

Main outcome measurements: The primary outcome measure was the miss rate for adenomas between patients who underwent CFC first and patients who underwent regular colonoscopy first.

Results: 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).

Limitations: Single-center study with two endoscopists.

Conclusion: CFC reduces miss rates for all adenomas and specifically for small adenomas. (

Clinical trial registration number: NCT00577083).