For Resection Without Injection, Histologic Study Indicates Underwater Gives Most Complete Resection
Douglas K. Rex, MD, MASGE, reviewing Toyosawa J, et al. Endosc Int Open 2022 May.
Previous studies have indicated that cold snare polypectomy effectively removes colorectal lesions up to 15 mm in size but cuts more superficially than hot snare polypectomy. Understanding the relative depth of resection is important, particularly when encountering lesions with the potential for cancer, where a deeper depth of resection is preferred.
In a study of consecutive 6- to 9-mm lesions without endoscopic features of cancer, 53 lesions were removed, including 13 excluded from the study because of challenges in measuring resection depth. Of 14 lesions removed by cold snare polypectomy, muscularis mucosa (MM) was present in 57% and submucosa (SM) in 29%. Of 12 lesions removed by hot snare polypectomy, MM was present in 92% and SM in 83%. Of 14 removed by underwater EMR (UEMR), MM and SM were present in 100% and 100%. The mean thickness of resected SM tissue was 52 microns with cold snare, 623 microns with hot snare, and 1119 microns with UEMR.
COMMENTAlthough these results do not diminish the numerous studies showing the clinical effectiveness of complete resection by cold snare for polyps in this size range, I translate this result to an approach in which lesions up to 20 to 30 mm in size are resected when they have features suspicious for cancer. Namely, UEMR has a significant chance of achieving en bloc resection (based on previous studies comparing UEMR with conventional EMR), and UEMR achieves a substantial resection depth that could be important in assessments of any submucosal invasion.
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)
Toyosawa J, Yamasaki Y, Fujimoto T, et al. Resection depth for small colorectal polyps comparing cold snare polypectomy, hot snare polypectomy and underwater endoscopic mucosal resection. Endosc Int Open 2022;10:E602-E608. (https://dx.doi.org/10.1055%2Fa-1785-8616)
