Clinical Outcomes of Underwater versus Conventional Endoscopic Mucosal Resection in the Removal of Sessile or Flat Colorectal Polyps ≥10 mm: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Abstract

Background and Aims: Underwater endoscopic mucosal resection (U-EMR) and conventional endoscopic mucosal resection (C-EMR) are the primary techniques for the removal of colorectal polyps. The purpose of this study is to conduct a meta-analysis on the safety and efficacy of the two procedures, U-EMR and C-EMR.

Methods: We searched multiple databases for randomized controlled trials (RCTs) comparing U-EMR and C-EMR for the resection of sessile or flat colorectal polyps. Standard meta-analytic methods were employed using random-effects, and I² % was used to assess heterogeneity.

Results: A total of seven RCTs were included. Regarding the en bloc resection rate, U-EMR was superior to C-EMR [Risk Ratio (RR) 1.13, 95% confidence interval (CI): 1.02–1.24]. Subgroup analysis showed that the higher en bloc resection rate of U-EMR was mainly manifested in 10-20 mm polyps (RR=1.16, 95%CI: 1.07-1.25). In the analysis of R0 resection rate, U-EMR outperformed C-EMR (RR=1.28, 95%CI: 1.02–1.61). In terms of the incidence of adverse events and recurrence rate, U-EMR showed a trend lower than C-EMR in terms of intraoperative bleeding [odds ratio (OR) 0.83, 95%CI: 0.45-1.54), delayed bleeding (OR=0.61, 95%CI: 0.28-1.32), and recurrence rate (OR=0.53, 95%CI: 0.24-1.18), but none of them reached statistical significance. For procedure time, U-EMR demonstrated shorter resection times than C-EMR [mean difference (MD) –3.05 minutes, 95%CI: –5.17 to –0.92).

Conclusions: For sessile or flat colorectal polyps measuring ≥10 mm in diameter, U-EMR demonstrates superior efficacy compared with C-EMR.