Oncologic safety and technical feasibility of completion transanal total mesorectal excision after local excision; a cohort study from the International TaTME Registry

Background: As part of an organ sparing strategy, a surgical local excision may be performed in patients with early-stage rectal cancer or following neoadjuvant (chemo)radiotherapy. In selected cases, a completion total mesorectal excision may be recommended which can be more complex because of the preceding local excision. A transanal approach to perform completion total mesorectal excision may offer an advantage through the better visualization of the surgical field in the distal rectum and less forceful retraction for exposure. However, the oncologic safety and technical feasibility of this approach have yet to be demonstrated in these patients. Therefore, the aim of this study was to evaluate the oncological and technical safety of completion transanal total mesorectal excision following a local excision in patients with rectal cancer. Methods: Patients from the prospective International Transanal Total Mesorectal Excision Registry who underwent a surgical local excision prior to completion transanal total mesorectal excision were retrospectively analyzed. Results: In total, 189 patients were included of which 22% received neoadjuvant radiotherapy. In 94% of the patients, a low anterior resection was performed. A primary anastomosis was constructed in 91% (n = 171/189) of the patients, with the majority also receiving a defunctioning stoma (84%, n = 144/171), of which 69% (n = 100/144) were reversed. Within 30 days, 7% developed an anastomotic leakage. The two-year local recurrence rate was 5% (n = 5/104) with an estimated rate of 3% (95% CI 0–7%). Two-year disease-free survival was 85% (n = 88/104) and overall survival was 95% (n = 99/104). Conclusions: Transanal completion total mesorectal excision following local excision for rectal cancer is oncologically safe, with low complication rates and high restorative rates.