Reduced adenoma miss rate with two versus a single forward-view examination of the proximal colon: a prospective, randomized tandem trial

Missed lesions in the proximal colon are a common cause of interval colorectal cancers detected before the next surveillance colonoscopy. This study aimed to determine whether two forward-view examinations of the proximal colon could reduce the adenoma miss rate compared to a single forward-view examination. Patients undergoing screening colonoscopy were enrolled in the study. After completing the first forward-view examination of the proximal colon (pass 1), patients were randomly assigned to either the intervention group, in which the proximal colon was re-examined twice (pass 2 and 3), or the control group, in which it was re-examined once (pass 2). The primary outcome was the proximal adenoma miss rate, defined as the number of proximal adenomas detected in the final pass (pass 3 for the intervention group and pass 2 for the control group) divided by the total number of proximal adenomas detected in that group. A total of 403 patients were enrolled (intervention group, n = 202; control group, n = 201). The proximal adenoma miss rate in the intervention group was significantly lower than that in the control group (10.8%; 95% CI 6.5% − 17.2% vs. 28.1%; 95% CI 20.7% − 36.9%, P < 0.001). The proximal polyp miss rate (16.0%; 95% CI 12.4% − 20.3% vs. 35.5%; 95% CI 30.2% − 41.3%, P < 0.001)and the proximal sessile serrated lesions miss rate (12.0%; 95% CI 3.2% − 32.3% vs. 40.0%; 95% CI 20.0% − 63.6%, P = 0.03) in the intervention group were also lower than those in the control group. Multivariate analysis showed that adenomas detected on the first proximal colon examination and the use of a single forward-view examination were both independent predictors of missed adenomas on the first withdrawal from the proximal colon. Two forward-view examinations of the proximal colon significantly reduced the proximal adenoma miss rate, proximal polyp miss rate and proximal sessile serrated lesions miss rate in patients undergoing screening colonoscopy. The study was registered by the Third People’s Hospital of Jingdezhen on ClinicalTrials.gov (Number: NCT 05712304; Date: 2023/01/25).