Underwater vs Conventional Endoscopic Mucosal Resection of Large Sessile or Flat Colorectal Polyps: A Prospective Randomized Controlled Trial.

BACKGROUND & AIMS: Conventional endoscopic mucosal resection (CEMR) with submucosal injection is the current standard for the resection of large, nonmalignant colorectal polyps. We investigated whether underwater endoscopic mucosal resection (UEMR) is superior to CEMR for large (20-40mm) sessile or flat colorectal polyps. METHODS: In this prospective randomized controlled study, patients with sessile or flat colorectal polyps between 20 and 40 mm in size were randomly assigned to UEMR or CEMR. The primary outcome was the recurrence rate after 6 months. Secondary outcomes included en bloc and R0 resection rates, number of resected pieces, procedure time, and adverse events. RESULTS: En bloc resection rates were 33.3% in the UEMR group and 18.4% in the CEMR group (P = .045); R0 resection rates were 32.1% and 15.8% for UEMR vs CEMR, respectively (P = .025). UEMR was performed with significantly fewer pieces compared to CEMR (2 pieces: 45.5% UEMR vs 17.7% CEMR; P = .001). The overall recurrence rate did not differ between both groups (P = .253); however, subgroup analysis showed a significant difference in favor of UEMR for lesions of >30 mm to ≤40 mm in size (P = .031). The resection time was significantly shorter in the UEMR group (8 vs 14 minutes; P < .001). Adverse events did not differ between both groups (P = .611). CONCLUSIONS: UEMR is superior to CEMR regarding en bloc resection, R0 resection, and procedure time for large colorectal lesions and shows significantly lower recurrence rates for lesions >30 mm to ≤40 mm in size. UEMR should be considered for the endoscopic resection of large colorectal polyps.

Complication risk despite preventive endoscopic measures in patients undergoing endoscopic mucosal resection of large duodenal adenomas.

BACKGROUND : Endoscopic mucosal resection (EMR) is the standard treatment of ampullary and nonampullary duodenal adenomas. EMR of large (10-29 mm) and giant (≥ 30 mm) lesions carries a risk of complications such as delayed bleeding and perforation. Prospective data on duodenal EMR are scarce. This study aimed to evaluate the efficacy of endoscopic procedures (clipping and coagulation of visible vessels) to prevent complications after EMR of large and giant lesions. METHODS : 110 patients with 118 adenomas (29 ampullary and 89 nonampullary) were included prospectively. RESULTS : 15 lesions were small (12.7 %), 68 were large (57.6 %), and 35 were giant (29.7 %). Endoscopic prevention of delayed complications was performed in 81.4 % (n = 96) of all lesions and 94.3 % (n = 33) of giant lesions. Complete resection was achieved in 111 lesions (94.1 %). Complications were 22 delayed bleedings (18.6 %), 3 intraprocedural perforations (2.5 %), 2 delayed perforations (1.7 %), and 1 stricture (0.8 %). Major complications were associated with lesions size ≥ 30 mm (28.6 % vs. 9.6 %; P = 0.02) and ampullary adenomas (27.6 % vs. 11.2 %; P = 0.07). All minor bleeding and 75 % of major bleeding episodes were treated endoscopically; 25 % of major bleedings needed radiologic embolization. Two fatal courses were observed when delayed perforation occurred after EMR of giant lesions. Residual adenoma was detected in 20.4 % at first follow-up. CONCLUSIONS : EMR of giant duodenal neoplasia carries a substantial risk of major complications and recurrences. Resection technique and prevention of delayed complications need to be improved. Further measures should be evaluated in randomized studies.