Total mesorectal excision for low and middle rectal cancer: laparoscopic versus transanal approach-a meta-analysis

Transanal total mesorectal excision (TaTME) appeared to be a challenging alternative to Laparoscopic Total Mesorectal Excision (LaTME) for low and middle rectal cancer. However, evidence remains low on the possible benefits of TaTME. The aim of this study was to perform a meta-analysis of comparative studies between TaTME and LaTME.

A systematic review and meta-analysis based on Preferred Reporting Items for Systematic reviews and Meta-analysis (PRISMA) guidelines was conducted on Medline, Embase, and Cochrane database. The following outcomes were assessed: conversion, operative time, morbidity, length of stay, readmission rate, and pathological and oncological results.

After review of 756 identified records, 14 studies were included (case-matched control n = 10, prospective cohort n = 3, retrospective study n = 1) comparing 495 TaTME and 547 LaTME. No randomized trial was available. Following criteria were significantly improved after TaTME vs. LaTME: readmission's rate (9% after TaTME vs. 18% after LaTME, OR 0.44, 95%CI 0.26-0.74, p = 0.002), length of stay (OR - 2.17, 95%CI - 3.68 to - 0.66, p = 0.005), overall morbidity (34 vs. 41%, OR 0.65, 95%CI 0.46-0.91, p = 0.001), major morbidity (8.7 vs. 14%, OR 0.53, 95%CI 0.34-0.83, p = 0.005), anastomotic leak (6.4 vs. 11.6%, OR 0.53, 95%CI 0.31-0.93, p = 0.03), and circumferential resection margin (CRM) involvement (4 vs. 8.8%, OR 0.48, 95%CI 0.27-0.86, p = 0.01). No significant differences were observed between TaTME and LaTME regarding conversion's rate (3.2 vs. 8.8%, p = 0.09), operative time (OR - 10.73, p = 0.26), intraoperative complications (8.1 vs. 6.3%, p = 0.48), minor morbidity (27.9 vs. 29.6%, p = 0.27), positive distal resection margin (1.4 vs. 1.4%, p = 0.93), complete TME (75 vs. 75%, p = 0.74), harvested lymph nodes (OR 0.38, p = 0.44), and local recurrence rate (3.5 vs. 2.2%, p = 0.64).

This meta-analysis based on nonrandomized studies suggests that TaTME seems better than LaTME in terms of overall and major morbidities, anastomotic leak, readmission rate, CRM involvement, and length of stay. These results need to be confirmed by randomized controlled trial.