Water immersion sigmoidoscopy versus standard insufflation for colorectal cancer screening: A cohort study.

Background Although the efficacy of water-assisted colonoscopy is well established, the role of water immersion sigmoidoscopy (WIS) remains unclear. We compared WIS with carbon dioxide insufflation sigmoidoscopy (CO2S) on patient outcomes. Methods We conducted an analysis of prospectively collected data from a single-center quality improvement program about patients undergoing unsedated screening sigmoidoscopy (WIS and CO2S) between May 2019 and January 2020. Outcomes studied included the following: Rates of severe pain 75% (proportion of Boston Bowel Preparation Scale score: 2-3) and adenoma detection rate (ADR). Results In total, 234 patients (111 WIS; 123 CO2S) were included. All patients were aged 58 years and 58.9% were female; baseline characteristics were comparable between groups. There were no significant differences in rates of severe pain (WIS: 16.5%, CO2S: 13.8%; P = 0.586), willingness to repeat the unsedated procedure (WIS: 82.3%, CO2S: 84.5%; P = 0.713), adequate bowel cleanliness (WIS: 78.4%, CO2S: 78%, P = 0.999) or ADR (WIS: 25.2%, CO2S: 16.3%; P = 0.106) between groups. However, average procedure times were longer with WIS (9.06 min) compared to CO2S (6.45 min; P < 0.001). Overall, 29.6% of women reported that they would repeat sigmoidoscopy only if sedated. Conclusions WIS does not ameliorate tolerance to and quality of sigmoidoscopy screening measured by several scores. When offered a choice, the women's willingness to repeat WIS or CO2S without sedation was poor and raises concern on the opportunity of screening sigmoidoscopy without sedation in these subjects.