Endoscopists who used the underwater endoscopic mucosal resection method were able to increase the proportion of R0 resections in patients with intermediate-size colorectal polyps.
Noriya Uedo, of the department of gastrointestinal oncology at the Osaka International Cancer Institute in Japan, and colleagues wrote that en bloc resection rates in traditional endoscopic mucosal resection (EMR) decreased as polyps increased in size larger than 10 mm, which led to piecemeal resection and an increased recurrence rate.
“Underwater EMR has emerged as an alternative to conventional EMR and is reported to be effective for removing flat or large colorectal polyps,” they wrote. “With underwater EMR, the bowel lumen is filled with water instead of air/CO2, and the lesion is captured and resected with a snare without submucosal injection of normal saline.”
Researchers conducted a randomized controlled trial at five Japanese centers composed of 210 patients with endoscopically diagnosed, intermediate size sessile colorectal lesions (10-20 mm). They randomly assigned patients to undergo either underwater EMR (n = 108) or conventional EMR (n = 102) and compared the difference in the R0 resection — defined as en bloc resection with a histologically confirmed negative resection margin — rates between the two groups after assessing just the most proximal lesion.
Uedo and colleagues found that the proportion of R0 resections was higher in the underwater EMR group (69%; 95% CI, 59%–77%) compared with the conventional EMR group (50%; 95% CI, 40%–60%; P = .011). The proportions of en bloc resections were also higher in the underwater EMR group (89%; 95% CI, 81%–94%) compared with the conventional group (75%; 95% CI, 65%–83%).
Additionally, there were no significant differences between groups in the median procedure time or proportion of patients with adverse events.
“Our randomized study suggests that underwater EMR significantly increases the R0 and en bloc resection rates without increasing the incidence of adverse events and procedure time,” Uedo and colleagues concluded. “On the basis of this evidence, the use of underwater EMR should be encouraged.” – by Alex Young
Disclosures: The authors report no relevant financial disclosures.