Impact of Colonoscopy Insertion Techniques on Adenoma Detection

Low adenoma detection rate (ADR) predicts development of interval cancers, found mainly in the right (cecum-ascending) colon, where poor bowel preparation is an associated factor. Single-site studies reported increased detection of adenomas in the proximal colon segments by water exchange (WE). Data about colon cleansing revealed that WE had the greatest impact in the right colon. To test the hypothesis that WE had the greatest impact on ADR in colon segments with the most favorable bowel cleanliness scores, namely the right colon. We pooled right colon and overall ADR data of three similarly designed colonoscopy trials that compared WE, water immersion (WI) and insufflation of air or carbon dioxide (AICD) in a mixed gender European population. In this study, 1200 (704 males) subjects and were included. 288 were screening cases. Demographic and procedural data were comparable. Water exchange achieved significantly higher right colon < 10 mm ADR (11.9 %, vs WI 6.9 %, p = 0.016; vs AICD 7.2 %, p = 0.025). Water exchange achieved the lowest proportions of poor bowel preparation and the highest right colon and overall Boston bowel preparation scale scores (p range 0.003, < 0.0005). In patients with right colon excellent bowel cleanliness, water exchange was the only method significantly associated with right colon adenoma detection. One of the limitations is unblinded colonoscopists. In a mixed gender European population, water exchange is confirmed to be a superior insertion technique showing a significant increase in < 10 mm right colon adenoma detection, achieving the cleanest colon and lowest proportions of poor bowel preparation requiring repeat procedures. NCT01781650, 01954862, 01780818.