Underwater versus conventional endoscopic mucosal resection for sessile colorectal polyps: an updated systematic review and meta-analysis

Rev Esp Enferm Dig. 2022 Sep 23. doi: 10.17235/reed.2022.8956/2022. Online ahead of print.


Background: Underwater endoscopic mucosal resection (uEMR) without submucosal injection for sessile colorectal polyps was introduced as a newer replacement for conventional EMR (cEMR). However, the optimal resection strategy remains a topic of debate. Hence, this meta-analysis was conducted to compare the efficacy and safety of uEMR and cEMR in patients with sessile colorectal polyps.

Methods: A comprehensive search of literature from 2000 till January 2022 from MEDLINE, CENTRAL and EMBASE for randomized controlled trials (RCTs) comparing cEMR vs. uEMR for colorectal polyps. The evaluated outcomes included En-bloc resection, R0 resection, procedural time, overall bleeding, and recurrence. Pooled risk ratios (RR) with 95% confidence interval were calculated using a random effect model.

Results: Six studies were included out of which four were full-text articles and two were conference abstracts. En-bloc resection (RR 1.26, 95% CI 1.00 - 1.60), R0 resection (RR 1.10, 95% CI 0.96 - 1.26), overall bleeding (RR 0.85, 95% CI 0.54 - 1.34) and recurrence rate (RR 0.75, 95% CI 0.45 - 1.27) were comparable between uEMR and cEMR. However, uEMR was associated with a lower procedural time (Mean difference -1.55 minutes, 95% CI -2.71 to -0.39). On subgroup analysis, uEMR led to a higher rate of en-bloc resection (RR 1.41, 95% CI 1.07 - 1.86) and R0 resection (RR 1.19, 95% CI 1.01 - 1.41) for polyps with size ≥ 10 mm.

Conclusion: Both uEMR and cEMR have comparable safety and efficacy. For polyps larger than 10 mm, uEMR may have an advantage over cEMR and should be the topic for future studies.