Underwater cap-suction pseudopolyp formation for endoscopic mucosal resection: a simple technique for treating flat, appendiceal orifice or ileocecal valve colorectal lesions

Background We aimed to evaluate the safety and technical success of an easy- to-use technique that applies underwater cap suction pseudopolyp formation to facilitate the resection of flat lesions or those at the appendiceal orifice or ileocecal valve. Methods We retrospectively analyzed a register of consecutive cap suction underwater endoscopic mucosal resection ( CAP- UEMR) procedures performed at two centers between September 2020 and December 2021. Procedures were performed using a cone- shaped cap, extending 7mm from the endoscope tip, to suction the lesion while submerged underwater, followed by underwater snare resection. Our primary end point was technical success, defined as macroscopic complete resection. Results We treated 83 lesions (median size 20 mm; interquartile range [IQR] 15-30mm) with CAP-UEMR: 64 depressed or flat lesions (18 previously manipulated, 9 with difficult access), 11 from the appendix, and 8 from the ileocecal valve. Technical success was 100 %. There were seven intraprocedural bleedings and two delayed bleedings, all managed endoscopically. No perforations or other complications occurred. Among the 64 lesions with follow-up colonoscopy, only one recurrence was detected, which was treated endoscopically. Conclusions CAP-UEMR was a safe and effective technique for removing nonpolypoid colorectal lesions, including those arising from the appendiceal orifice or ileocecal valve.