Cutting Plane Between Underwater and Conventional EMR Is Similar

Cutting Plane Between Underwater and Conventional EMR Is Similar

Douglas K. Rex, MD, MASGE, reviewing Matsueda K, et al. J Gastroenterol Hepatol 2022 Jan 2.

Randomized controlled trials (RCT) show that underwater EMR (UEMR) is more likely than conventional EMR (CEMR) to result in en bloc and R0 resection for 10- to 30-mm colorectal polyps. 

In a post hoc analysis of an RCT with 210 colorectal lesions that were 10 to 20 mm in size, one pathologist and two gastroenterologists reviewed the resection depth of the specimens from UEMR and CEMR and found them to be similar for maximum depth of the submucosal layer (1317 vs 1290 microns, respectively; P=.52) and mean depth of submucosa (619 vs 545 microns, respectively; P=.32).

Douglas K. Rex, MD, FASGE


Recent data have indicated that a disadvantage of cold resection is a more superficial cutting plane, sometimes failing to remove the muscularis mucosa. Thus, a more superficial cutting plane could result in a higher recurrence rate. In the case of en bloc resections, a superficial cutting plane could leave submucosal invasion on the resection line. This study establishes that UEMR, already known to produce more en bloc R0 resections among intermediate-sized lesions, also produces a similar depth of submucosa in the specimen compared with CEMR.

Note to readers: At the time we reviewed this paper, its publisher noted that it was not in final form and that subsequent changes might be made.


Matsueda K, Takeuchi Y, Kitamura M, et al. Depth of the cutting plane with underwater and conventional endoscopic mucosal resection: post hoc analysis of a randomized study. J Gastroenterol Hepatol 2022 Jan 2. (Epub ahead of print) (

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