Comparison of adenoma miss rate and adenoma detection rate between conventional colonoscopy and colonoscopy with second generation distal attachment cuff: a multicenter, randomized, back-to-back trial

Background and aims Endocuff VisionTM has been designed to enhance mucosal visualization thereby improving detection of (pre-)malignant colorectal lesions. This multicenter, international, back-to-back, randomized colonoscopy trial compared adenoma detection rate (ADR) and adenoma miss rate (AMR) between Endocuff Vision-assisted colonoscopy (EVC) and conventional colonoscopy (CC). Methods Patients aged 40-75 years referred for non-immunochemical fecal occult blood test-based screening, surveillance, or diagnostic colonoscopy were included at ten hospitals and randomized into four groups: Group 1; 2xCC, Group 2; CC followed by EVC, Group 3; EVC followed CC and Group 4; 2xEVC. Primary outcomes included ADR and AMR. Results A total of 717 patients were randomized of which 661 patients (92.2%) had one and 646 (90.1%) patients had two completed back-to-back colonoscopies. EVC did not significantly improve ADR compared to CC (41.1% [95%-CI;36.1-46.3] versus 35.5% [95%-CI;30.7-40.6], respectively, P=0.125), but EVC did reduced AMR by 11.7% (29.6% [95%-CI;23.6-36.5] versus 17.9% [95%-CI;12.5-23.5], respectively, P=0.049). AMR of 2xCC compared to 2xEVC was also not significantly different (25.9% [95%-CI;19.3-33.9] versus 18.8% [95%-CI;13.9-24.8], respectively, P=0.172). Only 3.7% of the polyps missed during the first procedures had advanced pathologic features. Factors affecting risk of missing adenomas were age (P=0.002), Boston Bowel Preparation Scale (P=0.008) and region where colonoscopy was performed (P<0.001). Conclusions Our trial shows that EVC reduces the risk of missing adenomas but does not lead to a significant improved ADR. Remarkably, 25% of adenomas are still missed during conventional colonoscopies, which is not different from miss rates reported 25 years ago; reassuringly, advanced features were only found in 3.7% of these missed lesions. Trail registration number NCT03418948