Optimal "total mesorectal excision"-open, laparoscopic, robotic or transanal?

Background Total mesorectal excision (TME) has led to a significant improvement in the prognosis of patients with rectal cancer. TME may be performed using a variety of approaches; however, there is ongoing discussion regarding which technique is optimal. Objectives Based on the current literature, the different TME approaches with a focus on randomized trials with oncologic endpoints are reviewed and discussed. Materials and methods A literature search was done using the terms "rectal cancer", "open total mesorectal excision", "laparoscopic total mesorectal excision", "robotic total mesorectal excision", "transanal total mesorectal excision". Results TME has led to a decrease of local recurrence to less than 10%. Open and laparoscopic TME do not differ in local recurrence rate, disease-free survival and overall survival. To date, no oncologic long-term results on robotic TME are available. In individual subgroups, more favorable functional results after robotic TME are indicated. Using transanal TME, results were comparable to those with laparoscopic TME, but in some centers it was associated with high rates of early and multifocal recurrence. Conclusions Laparoscopic TME has shown advantages over open TME in the early postoperative course and seems to be equivalent in long-term oncologic endpoints. No advantage in primary endpoints for robotic TME over laparoscopic TME has been demonstrated. Transanal TME is technically demanding procedure with a flat learning curve. To date, robotic and transanal TME cannot be regarded as standard surgical procedures in the treatment of rectal cancer.