Long-term oncologic outcomes after transanal total mesorectal excision: a single-center cohort with a minimum of 5-year follow-up.

BACKGROUND: Transanal total mesorectal excision (TaTME) has gained increasing popularity for low to mid rectal cancer. Several studies have reported on short-term oncological outcomes and safety of this procedure, however, data regarding long-term outcomes are sparse. We aimed to evaluate the long-term oncologic and survival outcomes of patients who underwent TaTME at our center. METHODS: This study is based on our prospectively maintained TaTME database. We only included patients who had a minimum follow-up of five years. The primary endpoints were incidence of local recurrence (LR), distant recurrence (DR), overall survival (OS), and disease-free survival (DFS). Secondary endpoints included pathological outcomes and postoperative complications. We used the reverse Kaplan Meier method to calculate follow-up time, and the cumulative incidence function to calculate the probability of LR and DR, accounting for competing risks and avoiding biased estimation. We calculated subdistribution hazard ratios (SHRs) to assess the association between clinically relevant patient, disease, and pathology variables and disease recurrence (LR and DR separately). RESULTS: A total of 220 patients were included (160 male patients). At the time of analysis, 60.91% were alive, and 58.6% were alive and disease free. The incidence of LR at five years was 4.55%, and the incidence of DR was 15.94%. Anastomotic leakage was the only predictor of LR (SHR: 4.01, P = 0.012), while both pathologically positive nodal status and anastomotic leakage were significant predictors of DR (SHR: 3.58, P = 0.001 and SHR: 3.91, P = 0.008, respectively). CONCLUSION: We observed acceptable oncologic and survival outcomes following TaTME. Anastomotic leakage emerged as the strongest predictor of disease recurrence, underscoring the importance of meticulous surgical technique and optimal perioperative care in improving long-term oncologic outcomes.