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: This study aimed 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 patients receiving transanal or anterior total mesorectal excision (open or laparoscopic) for nonmetastatic primary rectal cancer in 2015 to 2016 were included. 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 2 years, and multivariable Cox regression was used to assess 2-year disease-free survival. Results are expressed with their 95% CIs. 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 subhazard ratio 1.28, 95% CI 0.55-2.96). There were no statistical differences in the comparative rate of local recurrence (transanal: 1.77 per 100 person-years, 95% CI 0.76-3.34; anterior: 1.37 per 100 person-years, 95% CI 0.8-2.15) or mortality (transanal: 3.98 per 100 person-years, 95% CI 2.36-6.16; anterior: 2.99 per 100 person-years, 95% CI 2.1-4.07). Groups presented similar 2-year cumulative incidence of local recurrence (4.83% versus 3.57%) and disease-free survival (HR, 1.33; 95% CI 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.