Transanal total mesorectal excision versus anterior total mesorectal excision for rectal cancer: a propensity-score matched, population-based study in Catalonia, Spain

Background: the clinical value of transanal total mesorectal excision is debated. Objective: to compare short- and medium-term effects of transanal versus anterior total mesorectal excision for rectal cancer. Design: this was a multicenter retrospective cohort study. Setting: the study included all Catalonian public hospitals. Patients: all non-metastatic patients receiving transanal or anterior total mesorectal excision (open or laparoscopic) for primary rectal cancer in 2015-16. Main outcome measures: data on vital status were collected to March 2019. Between-group differences were minimized by applying propensity score matching to baseline patient characteristics. Competing risk models were used to assess systemic and local recurrence along with death at two years, and multivariable Cox regression to assess two-year disease-free survival. Results are expressed with their 95% confidence intervals. Results: the final subsample was 537 patients receiving total mesorectal excision (transanal approach: n=145; anterior approach: n=392). Median follow-up was 39.2 months (interquartile range 33.0-45.8). Accounting for death as a competing event, there was no association between transanal total mesorectal excision and local recurrence (matched sub-hazard ratio 1.28, 0.55-2.96). There were no statistical differences in the comparative rate of local recurrence (transanal: 1.77 per 100 person-years, 0.76-3.34; anterior: 1.37 per 100 person-year, 0.8-2.15) or mortality (transanal: 3.98 per 100 person-year, 2.36-6.16; anterior: 2.99 per 100 person-years, 2.1-4.07). Groups presented similar two-year cumulative incidence of local recurrence (4.83% versus 3.57%, respectively) and disease-free survival (hazard ratio 1.33, 0.92-1.92). Limitations: we used data only from the public system, the study is retrospective, and data on individual surgeons are not reported. Conclusion: these population-based results support the use of either the transanal, open, or laparoscopic approach for rectal cancer in Catalonia. See Video Abstract at http://links.lww.com/DCR/B744