Comparison of early experience of robotic and transanal total mesorectal excision using propensity score matching

Robotic surgery and transanal minimally invasive surgery are the two recently developed techniques, which can overcome the difficult pelvic dissection in conventional laparoscopy. This study aimed to compare the early cases of robotic and transanal total mesorectal excision (taTME) using propensity score matching.

The first 40 cases of taTME and the first 80 sphincter-saving robotic total mesorectal resection for rectal cancer were selected from the prospectively collected database. Using propensity score matching, the outcomes of 40 matched cases of robotic TME were compared with the 40 cases of taTME.

Before matching, patients in the taTME group were significantly younger. The tumors were smaller but more distally located. Significantly more patients in the taTME group received preoperative chemoradiation. After matching, the two groups did not show any differences in gender, age, comorbidity, the level of tumors, and incidences of preoperative chemoradiation. The operating time was significantly shorter (254 vs. 170 min, p < 0.05) and the blood loss was less (50 vs. 150 ml, p = 0.002) in the taTME group. Conversion rate was 5% in both groups. There was no difference in the hospital stay, overall morbidity, the anastomotic leakage rate, and the urinary complication rate between the two groups. More patients in the taTME group did not require a separate abdominal incision. The distal margin, the number of lymph nodes examined, and the rate positive circumferential margin (0 vs. 5%, p = 0.494) were also similar between the two groups.

Both taTME and robotic surgery can achieve favorable outcomes in the rectal cancer resection. Comparison of the early experience of the two procedures with propensity score matching showed the taTME was associated with a shorter operating time, less blood loss, and a higher rate of transanal extraction of the specimen. Further evaluation by randomized trials is warranted.