Median Thickness of Submucosa in the Resected Specimen Is Less With Underwater Than Conventional EMR for Polyps <20 mm
Douglas K. Rex, MD, MASGE, reviewing Nomura H, et al. Endosc Int Open 2022 May 30.
The thickness of submucosal tissue resection can be important for predicting whether the resection margin and submucosal assessment will be adequate when there is suspicion of submucosal invasion. Recent data suggest that resected submucosa is thicker with underwater endoscopic mucosal resection (UEMR) than with traditional hot snare or cold snare polypectomy.
In a retrospective study, propensity score matching was used to compare 54 lesions removed by 9 endoscopists using conventional EMR (CEMR) and 54 lesions removed by 4 endoscopists using UEMR. The median lesion size was 12 mm in both groups. All specimens in both groups contained submucosal tissue, but the median thickness of submucosa was lower in the UEMR group at 950 microns than in the CEMR group at 1235 microns.
COMMENTTwo recent studies have found that UEMR produces a submucosal thickness of about 1 mm. Previous randomized trials found that as lesion size increases, particularly in those ranging in size from 15 to 30 mm, UEMR produces more en bloc resections than CEMR. It is interesting that this study demonstrated no advantage for UEMR in the depth of submucosal tissue resected in lesions with a median size of 12 mm.
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.
CITATION(S)
Nomura H, Tsuji S, Utsonomiya M, et al. Resection depth and layer of underwater versus conventional endoscopic mucosal resection of intermediate-sized colorectal polyps: a pilot study. Endosc Int Open 2022 May 30. (Epub ahead of print) (https://doi.org/10.1055/a-1864-6452)
