Efficacy and Safety of Endoscopic Submucosal Dissection for Rectal Tumors Extending Versus Not to the Dentate Line A Systematic Review and Meta-Analysis

Goals: To evaluate the outcomes of endoscopic submucosal dissection (ESD) for rectal tumors extending to the dentate line (RTDLs) compared with rectal tumors not extending to the dentate line (non-RTDLs). Background: There is limited composite data on the outcomes of ESD for RTDLs versus non-RTDLs. Study: We performed a systematic review and meta-analysis of studies that reported the clinical outcomes of ESD for RTDLs and non-RTDLs. Main outcomes were pooled estimated rates of en bloc/complete/curative resection, local recurrence, and incidence of bleeding, perforation, stricture, anal pain, and fever. Results: Six studies were enrolled, including 265 cases of RTDLs and 788 cases of non-RTDLs. The en bloc resection rate was comparable for RTDLs and non-RTDLs [odds ratio (OR), 1.04; 95% confidence interval (CI), 0.55-1.95; P=0.90]. The complete resection rate was significantly lower for RTDLs (OR, 0.59; 95% CI, 0.41-0.83; P=0.003), as well as the curative resection rate (OR, 0.57; 95% CI, 0.38-0.87; P=0.010). The rates of stricture, postoperative anal pain and local recurrence were significantly higher for RTDLs than non-RTDLs (OR, 3.07; 95% CI, 1.01-9.31; P=0.05) (OR, 42.10; 95% CI, 4.73-374.97; P=0.0008) (OR, 3.00; 95% CI, 1.13-7.96; P=0.03), but the higher rates of postoperative bleeding and fever for RTDLs were not significantly (OR, 1.33; 95% CI, 0.53-3.30; P=0.54) (OR, 2.23; 95% CI, 0.55-9.07; P=0.26), as well as its lower perforation rate (OR, 0.85; 95% CI, 0.27-2.63; P=0.78). Conclusions: Despite its inferior outcomes than non-RTDLs, ESD is still a feasible and safe treatment for RTDLs if appropriate lesions are treated by experienced operators.