Peri-operative, oncological and functional outcomes of robotic versus transanal total mesorectal excision in patients with rectal cancer: A systematic review and meta-analysis

Background Comparative outcomes of robotic low anterior resection (rTME) and trans-anal total mesorectal excision (TaTME) in patients with low rectal cancer were evaluated. Methods A systematic online search was conducted using the following databases: PubMed, Scopus, Cochrane database, The Virtual Health Library, Clinical trials.gov and Science Direct. Comparative studies of rTME versus TaTME for low rectal cancer were included. Primary outcomes were postoperative complications, including anastomotic leak, surgical site infection, and Clavien–Dindo complication rate. Total operative time, conversion to open surgery, intra-operative blood loss, intensive therapy unit (ITU) and total hospital length of stay (LOS), oncological outcomes and functional outcomes were the other evaluated outcome parameters. Results A total of 12 studies with a total number of 3025 patients divided between rTME ( n = 1881) and TaTME ( n = 1144) groups were included. There was no significant difference between the two groups for total operative time ( P = 0.39), conversion to open surgery ( P = 0.29) and intra-operative blood loss ( P = 0.62). Clavien−Dindo ≥ 3 complication rate ( P = 0.47), anastomotic leak ( P = 0.89), rates of re-operation ( P = 0.62) and re-admission ( P = 0.92), R0 resections ( P = 0.52), ITU LOS ( P = 0.63) and total hospital LOS ( P = 0.30) also showed similar results between the two groups. However, the rTME group had higher rates of total harvested lymph nodes ( P = 0.04) and complete total mesorectal excision (TME) resections ( P = 0.05). Albeit with a limited dataset, the Wexner and low anterior resection syndrome (LARS) scores showed better functional results in the rTME group compared with the TaTME group ( P = 0.0009 and P = 0.00001, respectively). Conclusion Compared with TaTME, rTME seems to provide better functional outcomes, higher lymph node yield and more complete TME resections with a similar post-operative complications profile.