Transanal total mesorectal excision: pathological results of 186 patients with mid and low rectal cancer

Transanal total mesorectal excision (TaTME) seems to be a valid alternative to the open or laparoscopic TME. Quality of the TME specimen is the most important prognostic factor in rectal cancer. This study shows the pathological results of the largest single-institution series published on TaTME in patients with mid and low rectal cancer.

We conducted a retrospective cohort study of all consecutive patients with rectal cancer, treated by TaTME between November 2011 and June 2016. Patient data were prospectively included in a standardized database. Patients with all TNM stages of mid (5-10 cm from the anal verge) and low (0-5 cm from the anal verge) rectal cancer were included.

A total of 186 patients were included. Tumor was in the mid and low rectum in, respectively, 62.9 and 37.1%. Neoadjuvant chemoradiotherapy was given in 62.4%, only radiotherapy in 3.2%, and only chemotherapy in 2.2%. Preoperative staging showed T1 in 3.2%, T2 in 20.4%, T3 in 67.7%, and T4 in 7.5%. Mesorectal resection quality was complete in 95.7% (n = 178), almost complete in 1.6% (n = 3), and incomplete in 1.1% (n = 2). Overall positive CRM (≤ 1 mm) and DRM (≤ 1 mm) were 8.1% (n = 15) and 3.2% (n = 6), respectively. The composite of complete mesorectal excision, negative CRM, and negative DRM was achieved in 88.1% (n = 155) of the patients. The median number of lymph nodes found per specimen was 14.0 (IQR 11-18).

The present study showed good rates regarding total mesorectal excision, negative circumferential, and distal resection margins. As the specimen quality is a surrogate marker for survival, TaTME can be regarded as a safe method to treat patients with rectal cancer, from an oncological point of view.