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.