UNDERWATER- VERSUS CONVENTIONAL ENDOSCOPIC MUCOSAL RESECTION OF LARGE SESSILE OR FLAT COLONIC POLYPS: PRELIMINARY RESULTS OF A PROSPECTIVE RANDOMIZED CONTROLLED TRIAL

Aims Conventional endoscopic mucosal resection (CEMR) with submucosal injection is the current standard for the resection of large, non-malignant colonic polyps. Underwater EMR (UWEMR) is a novel technique and has been shown to be more effective than CEMR for colonic polyps up to 20 mm in size. In this study, we present preliminary results of a randomized, controlled trial to demonstrate the efficacy, safety and feasibility of UWEMR for large sessile or flat colonic polyps between 20 mm and 40 mm.

Methods Patients with sessile or flat colonic lesions between 20 and 40 mm in size were randomly assigned to UWEMR or CEMR. For this preliminary paper, we analyzed the outcome of 58 colonic lesions in the UWEMR group and 59 in the CEMR group as regards en bloc resection rate / number of resected pieces, complication rate and resection time.

Results Total en bloc resection rates were 27,6% in the UWEMR group vs 18,6% in the CEMR group (P = .2792). In case of piecemeal resection, UWEMR was performed with significantly fewer pieces compared to CEMR (2 - 3 pieces: 69% UWEMR vs 37,5% CEMR) (P = .0035). Mean resection time was 12.5 minutes for UWEMR and 18.0 minutes for CEMR (p=.481). Bleeding rates were similar in both groups (15,5% UEMR vs 16,9% CEMR) (P = 1.0) and no perforation occured in either groups.

Conclusions UWEMR is safe and feasible even for large colonic lesions with a trend towards a higher en bloc resection rate and a faster resection time as compared to CEMR. There were significantly fewer resected pieces in piecemeal UWEMR. Follow-up data on R0 resection as well as recurrence rates after 6 and 12 months will be presented subsequently.