Introduction Adenoma detection rate (ADR) is the most important measure of mucosal visualisation at lower gastrointestinal endoscopy. Higher ADRs are associated with lower post-colonoscopy colorectal cancer (PCCRC) rates with a 3% reduction in PCCRCs with every 1% increase in ADR. In the English flexible sigmoidoscopy screening programme (Bowel scope) there is also significant variation in ADRs across screening centres. Large studies have demonstrated improved detection rates during screening procedures utilising Endocuff Vision™ (EV). The aim of this study is to determine the effect of Endocuff Vision on ADR in a flexible sigmoidoscopy bowel cancer screening population.

Methods B-ADENOMA was a multicentre, randomised controlled trial involving 16 English Bowel scope screening centres, performed between February 2017 and April 2018. Patients attending for Bowel scope screening were randomised to Endocuff™-assisted Bowel scope (EAB) or Standard Bowel scope (SB). Adenoma Detection Rate (ADR) was compared between trial arms on an intention-to-treat basis. Secondary analyses compared Mean number of Adenomas per Procedure (MAP), Polyp Detection Rate (PDR), characteristics and location of polyps, procedural characteristics between arms and made comparisons with national Bowel scope data. Patient experience, procedure extent and complication rates were assessed for non-inferiority.

Results 3222 patients were randomised (53% male) to receive EAB (n=1610) or SB (n=1612). Baseline demographics were comparable between the two arms. ADR in the EAB arm was 13.3% and in the SB arm was 12.2% (p=0.353). Also, no statistically significant differences between arms were found in MAP, PDR, polyp morphology or location. Patient experience and complication rates were similar in both arms. The cuff exchange rate in the EAB arm was 4.2%. ADR in the SB arm was 3.1% higher than the national ADR (9.1%).

Conclusions EV did not improve Bowel scope ADR when compared with standard Bowel scope. ADR in both arms was higher than the national ADR. This suggests that, where detection rates are already high, use of EV does not improve detection further. Reasons for the high ADR in the SB arm require further exploration but may include selection effects at centre level and contamination effects at endoscopist level.