Endoscopic resection therapies for rectal neuroendocrine tumors: A systematic review and meta-analysis

Background and Aim: Among various endoscopic resection therapies, including conventional endoscopic mucosal resection (EMR) only with a snare after submucosal injection, modified EMR (m-EMR) with other assistant devices such as a ligation band or a suction cap, and endoscopic submucosal dissection (ESD), we aimed to study which is the best choice for rectal neuroendocrine tumors. Methods: A broad literature research was performed, and a systematic review and meta-analysis were conducted. Results: Ten retrospective studies with 650 patients were included. Complete resection rates were significantly higher in the ESD group compared with the EMR group (relative risk [RR] 0.89, 95% confidence interval [CI] [0.79, 0.99]), in the m-EMR group compared with the conventional EMR group (RR 0.72, 95% CI [0.60, 0.86]), and was comparable between the ESD group and the m-EMR group (RR 1.03, 95% CI [0.95, 1.11]). Procedure time was significantly longer in the ESD group than in the EMR group (standard mean differences -1.37, 95% CI [-1.99, -0.75]), but there was no significant difference between that of the m-EMR group and ESD group (standard mean differences -1.50, 95% CI [-3.14, 0.14]). Local recurrence occurred in five cases in the EMR group (5/328) and did not occur in the ESD group (0/209). Conclusions: ESD or m-EMR techniques could be applied to rectal neuroendocrine tumors with indications for endoscopic treatment. m-EMR procedures appear to be comparable with ESD in the treatment of rectal neuroendocrine tumors. However, the findings have to be carefully interpreted due to the lower level of evidence.