Systematic review of endoscopic mucosal resection versus transanal endoscopic microsurgery for large rectal adenomas

Background and study aims: Large (>2 cm) rectal adenomas are currently treated by either transanal endoscopic microsurgery (TEM) or piecemeal endoscopic mucosal resection (EMR). The potential lower morbidity of EMR may become irrelevant if EMR is less effective. The aim of this study was to compare the safety and effectiveness of EMR and TEM for large rectal adenomas. Patients and methods: A systematic review of the literature published between January 1980 and January 2009 was conducted. Pooled estimates of the proportion of patients with recurrence or complications in EMR and TEM studies were compared using random effects meta-regression analysis. Early (after single intervention) and late (excluding re-treatment of residual adenoma detected within 3 months) recurrence rates were calculated. Results: A total of 20 EMR studies and 48 TEM studies were included. No studies directly compared EMR with TEM. Mean polyp size was 31 mm (range 2-86 mm) for EMR vs. 37 mm (range 3-182 mm) for TEM (P =0.02). Early recurrence rates were 11.2% (95% confidence interval [CI] 6.0-19.9) for EMR vs. 5.4% (95 % CI 4.0-7.3) for TEM (P=0.04). Late recurrence rates were 1.5% (95 % CI 0.6-3.9) for EMR vs. 3.0% (95 % CI 1.3-6.9) for TEM (P= 0.29). Postoperative complication rates were 3.8% (95 % CI 2.8-5.3) for EMR vs. 13.0 % (95 % CI 9.8-17.0) for TEM (P<0.001). Conclusions: After single intervention, EMR for large rectal adenomas appears to be less effective but safer than TEM. When outcome data for re-treatment of residual adenoma within 3 months are included, EMR and TEM seem equally effective. Nevertheless, the added morbidity of additional EMRs could not be accounted for in this analysis. A prospective randomized trial seems imperative before making recommendations concerning the treatment of large rectal adenomas.