Abstract
Background Recently, underwater endoscopic mucosal resection (UEMR) has shown promising results
in the management of colorectal polyps. Some studies have shown better outcomes compared
to conventional endoscopic mucosal resection (EMR). We conducted this systematic review
and meta-analysis to compare UEMR and EMR in the management of colorectal polyps.
Methods We searched several databases from inception to November 2019 to identify studies
comparing UEMR and EMR. Outcomes assessed included rates of en bloc resection, complete
macroscopic resection, recurrent/residual polyps on follow-up colonoscopy, complete
resection confirmed by histology and adverse events. Pooled risk ratios (RR) with
95 % confidence interval were calculated using a fixed effect model. Heterogeneity
was assessed by I2 statistic. Funnel plots and Egger’s test were used to assess publication bias. We
used the Newcastle-Ottawa scale (NOS) for assessment of quality of observational studies,
and the Cochrane tool for assessing risk of bias for RCTs
Results Seven studies with 1291 patients were included; two were randomized controlled trials
and five were observational. UEMR demonstrated statistically significantly better
efficacy in rates of en bloc resection, pooled RR 1.16 (1.08, 1.26), complete macroscopic
resection, pooled RR 1.28 (1.18, 1.39), recurrent/residual polyps; pooled RR 0.26
(0.12, 0.56) and complete resection confirmed by histology; pooled RR 0.75 (0.57,
0.98). There was no significant difference in adverse events (AEs); pooled RR 0.68
(0.44, 1.05).
Conclusions This meta-analysis found statistically significantly better rates of en bloc resection,
complete macroscopic resection, and lower risk of recurrent/residual polyps with UEMR
compared to EMR. We found no significant difference in AEs between the two techniques.