Meta-analysis of transanal total mesorectal excision versus laparoscopic total mesorectal excision in management of rectal cancer.

Objectives: To evaluate comparative outcomes of transanal total mesorectal excision (TaTME) and laparoscopic TME (LaTME) in patients with rectal cancer.

Methods: We systematically searched multiple databases and bibliographic reference lists. A combination of free text and controlled vocabulary search adapted to thesaurus headings, search operators, and limits were applied. Overall intraoperative complications, overall postoperative complications, anastomotic leak, surgical site infections (SSIs), completeness of mesorectal excision, R0 resection, distal (DRM) and circumferential resection margin (CRM), number of harvested lymph nodes, and procedure time were the evaluated outcome parameters.

Results: We identified 18 comparative studies reporting a total of 2048 patients evaluating outcomes of TaTME (n = 1000) and LaTME (n = 1048) in patients with rectal cancer. TaTME was associated with significantly higher number of R0 resection (OR 1.67, P = 0.01) and harvested lymph nodes (MD 1.08, P = 0.01), and lower rate of positive CRM (OR 0.67, P = 0.04) and conversion to an open procedure (OR 0.17, P < 0.00001) compared with LaTME. However, there was no significant difference in intraoperative complications (OR 1.18, P = 0.54), postoperative complications (OR 0.89, P = 0.24), anastomotic leak (OR 0.88, P = 0.42), SSIs (OR 0.64, P = 0.26), completeness of mesorectal excision (OR 1.43, P = 0.19), DRM (MD 1.87, P = 0.16), CRM (MD 0.36, P = 0.58), and procedure time (MD - 10.87, P = 0.18) between TaTME and LaTME. Moreover, for low rectal tumours, TaTME was associated with significantly lower rate of anastomotic leak and higher number of lymph nodes (MD 2.06, P = 0.002).

Conclusions: Although the meta-analysis of best available evidence (level 2) demonstrated that TaTME may be associated with better short-term oncological outcomes and similar clinical outcomes compared with LaTME, the differences between the two groups were small questioning their clinical relevance. No solid conclusions can be made due to lack of high quality randomised studies.