Cold versus hot endoscopic mucosal resection for nonpedunculated colorectal polyps sized 6-10 mm: a randomized trial

Cold snare polypectomy is an established method for the resection of small colorectal polyps; however, significant incomplete resection rates still leave room for improvement. We aimed to assess the efficacy of cold snare endoscopic mucosal resection (CS-EMR), compared with hot snare endoscopic mucosal resection (HS-EMR), for nonpedunculated polyps sized 6 - 10 mm.

This study was a dual-center, randomized, noninferiority trial. Consecutive adult patients with at least one nonpedunculated polyp sized 6 - 10 mm were enrolled. Eligible polyps were randomized (1:1) to be treated with either CS-EMR or HS-EMR. Both methods involved submucosal injection of a methylene blue-tinted normal saline solution. The primary noninferiority end point was histological eradication evaluated by postpolypectomy biopsies (noninferiority margin - 10 %). Secondary outcomes included occurrence of intraprocedural bleeding, clinically significant postprocedural bleeding, and perforation.

Among 689 patients screened, 155 patients with 164 eligible polyps were included (CS-EMR n = 83, HS-EMR n = 81). The overall rate of histological complete resection was 92.8 % in the CS-EMR group and 96.3 % in the HS-EMR group (difference 3.5 %; 95 % confidence interval [CI] - 4.15 to 11.56), showing noninferiority of CS-EMR compared with HS-EMR. CS-EMR was shown to be noninferior both for polyps measuring 6 - 7 mm (CS-EMR 93.3 %; HS-EMR 100 %; 95 %CI - 7.95 to 21.3) and those of 8 - 10 mm (92.5 % vs. 94.7 %, respectively; 95 %CI - 7.91 to 13.16). Rates of intraprocedural bleeding were similar between the two groups (CS-EMR 3.6 %, HS-EMR 1.2 %; P  = 0.30). No clinically significant postprocedural bleeding or perforation occurred in either group.

CS-EMR appears to be a valuable modification of the standard cold snare technique, obviating the need to use diathermy for nonpedunculated colorectal polyps sized 6 - 10 mm.