Pathologic outcomes of transanal versus laparoscopic total mesorectal excision for rectal cancer: a meta-analysis of 26 studies.

Purpose: Transanal total mesorectal excision (TaTME) has the potential advantages for patients with low rectal cancer. The objective of this meta-analysis was to identify the pathologic outcomes between the TaTME and laparoscopic total mesorectal excision (LaTME) in rectal cancer.

Methods: The literature searches were conducted in PubMed, Cochrane Library, and EMBASE with English language restriction. The primary endpoint was circumferential margin (CRM), and the secondary endpoints were distal resection margin (DRM), mesorectal excision quality, and harvested lymph nodes.

Results: Our research identified 1090 articles, and 26 studies met the inclusion criteria for the meta-analysis. The positive CRM was lower in the TaTME than the LaTME (OR = 0.72; 95% CI = 0.53, 0.98; P = 0.04). There was no significant difference in the positive CRM between the TaTME and LaTME published after 2016 (OR = 0.80; 95% CI = 0.57, 1.12; P = 0.19), prospective study (OR = 2.70; 95% CI = 0.51, 14.24; P = 0.24), respective study (OR = 0.76; 95% CI = 0.55, 1.04; P = 0.09), BMI > 26 (OR = 1.00; 95% CI = 0.63, 1.58; P = 0.98), or sample size > 100 (OR = 0.84; 95% CI = 0.57, 1.23; P = 0.38). In addition, there was no significant difference observed between the TaTME and LaTME in terms of DRM, mesorectum incompleteness, and harvested lymph nodes.

Conclusions: The TaTME is associated with lower positive CRM compared to the LaTME and similar pathologic outcomes including DRM, harvested lymph node, and mesorectal excision quality.