American College of Gastroenterology Annual Meeting

American College of Gastroenterology Annual Meeting

November 13, 2019
1 min read

Underwater endoscopic mucosal resection viable alternative to conventional treatment

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SAN ANTONIO — Underwater endoscopic mucosal resection was a safe and effective alternative to conventional resection in patients with large laterally spreading colorectal tumors, according to study results presented at the American College of Gastroenterology Annual Meeting.

David P. Lee, MD, MPH, of the University of California Irvine Medical Center, said the technique involves replacing luminal air insufflation with water immersion, which allows for resection without the need for submucosal injections. Although previous studies have looked at the efficacy of underwater endoscopic mucosal resection (UEMR), they have mostly been restricted to cases series and retrospective analyses.

“That brings to our study, the objective of which was to compare the outcomes and safety of underwater EMR vs. conventional injection-assisted EMR,” Lee said in his presentation.

The study comprised 303 patients with large colon polyps at least 15 mm in size. Researchers randomly assigned the patients to undergo either UEMR (n = 158) or conventional EMR (n = 145; CEMR). The primary outcome of the study was rate of curative resection, which was documented by the presence of residual neoplasia on a 3- to 6-month surveillance colonoscopy.

During the study, 13 patients crossed from CEMR to UEMR, and one patient crossed from UEMR to CEMR.

Of the 95 patients who completed a surveillance colonoscopy in the CEMR arm, investigators identified residual neoplasia in 16 patients (16.8%). Among 118 patients who completed a follow-up colonoscopy in the UEMR arm, they identified residual neoplasia in 10 patients (8.5%; P = .06).

Additionally, researchers found that the resection time and total procedure time were lower in the UEMR arm, and patients in that group experienced a higher rate of en bloc resection compared with patients in the CEMR group (P < .01). There was also no difference in the rate of adverse events.

“This study adds to the broad body of literature demonstrating the safety and efficacy of underwater EMR technique,” Lee said.


Hamerski C, et al. Abstract 70. Presented at: American College of Gastroenterology Annual Meeting; Oct. 25-30, 2019; San Antonio.

Disclosures: Lee reports no relevant financial disclosures.