IntroductionTotal mesorectal excision (TME) is an essential component of surgical management of rectal cancer. Both open and laparoscopic TME have been proven to be oncologically safe. However, it remains a challenge to achieve complete TME with clear circumferential resections margin (CRM) with the conventional transabdominal approach, particularly in mid and low rectal tumours. Transanal TME (TaTME) was developed to improve oncological and functional outcomes of patients with mid and low rectal cancer.MethodsAn international, multicentre, superiority, randomised trial was designed to compare TaTME and conventional laparoscopic TME as the surgical treatment of mid and low rectal carcinomas. The primary endpoint is involved CRM. Secondary endpoints include completeness of mesorectum, residual mesorectum, morbidity and mortality, local recurrence, disease-free and overall survival, percentage of sphincter-saving procedures, functional outcome and quality of life. A Quality Assurance Protocol including centralised MRI review, histopathology re-evaluation, standardisation of surgical techniques, and monitoring and assessment of surgical quality will be conducted.DiscussionThe difference in involvement of CRM between the two treatment strategies is thought to be in favour of the TaTME. TaTME is therefore expected to be superior to laparoscopic TME in terms of oncological outcomes in case of mid and low rectal carcinomas.

Transanal TME appears associated with a significant higher rate of completeness of the mesorectum. Further studies are necessary to evaluate this novel technique.

TaTME is a safe alternative to standard laparoscopic TME in selected low-risk patients with rectal carcinoma when treated by an experienced colorectal team. In the future, randomized trials are necessary to prove its oncological safety.

Background: Laparoscopic resection of colorectal cancers is a safe alternative to open surgery. The conversion rate to open surgery remains fairly constant but is associated with increased morbidity. A new approach to the surgical excision of rectal cancer is transanal total mesorectal excision (TME), in which the rectum is mobilized peranally using endoscopic instruments. This feasibility study describes initial results with transanal TME. Conclusion:Transanal TME using the down-to-up principle is feasible. Whether the oncological and clinical results are comparable with those of standard laparoscopic or open TME has yet to be proven.

Patients undergoing laparoscopic or transanal TME showed comparable functional and QOL outcomes. Although the TaTME technique is still evolving, this study indicates that this technique is a safe alternative to laparoscopic surgery in terms of functional outcomes for mid and low rectal cancers.