To compare early oncological outcomes, particularly the R1 resection rate (defined as positive circumferential resection margin [CRM+] or distal resection margin [DRM+]), between transanal total mesorectal excision (TaTME) and laparoscopic total mesorectal excision (LaTME) for the treatment of rectal cancer.

This was a retrospective single-center case-control study including 58 patients matched for age, sex, and preoperative tumor stage, who underwent surgery between 2010 and 2020. The primary endpoint was the composite R1 resection rate. Secondary endpoints included pathological characteristics, local recurrence rates, progression-free survival, and postoperative complications.

The R1 resection rate was 14.3% in the TaTME group and 10.0% in the LaTME group ( P = 0.70). CRM+ was observed exclusively in the TaTME group (3.6%; P = 0.48). There were no statistically significant differences between groups regarding local recurrence rates (11.1% vs. 0%, P = 0.24), local progression-free survival (39.8 vs. 33.5 months, P = 0.44), or severe postoperative complications (Clavien-Dindo ≥ III: 25.0% vs. 20.0%, P = 0.41). A trend toward improved R1 resection rates with increasing surgical experience in TaTME was noted (30% initially vs. 0% in later cases, P = 0.17).

In this single-center study, TaTME did not demonstrate clear oncological superiority over LaTME but showed a potential for improvement with increased surgical experience. These findings underscore the importance of structured implementation and ongoing evaluation of the technique in controlled clinical settings.