Association of Surgical Approaches and Outcomes in Total Mesorectal Excision and Margin Status for Rectal Cancer

Despite being a key metric with a significant correlation with the outcomes of patients with rectal cancer, the optimal surgical approach for total mesorectal excision (TME) has not yet been identified. The aim of this study was to assess the association of the surgical approach on the quality of TME and surgical margins and to characterize the surgical and long-term oncologic outcomes in patients undergoing robotic, laparoscopic, and open TME for rectal cancer.

Patients with primary, nonmetastatic rectal adenocarcinoma who underwent either lower anterior resection or abdominoperineal resection via robotic (Rob), laparoscopic (Lap), or open approaches were selected from the US Rectal Cancer Consortium database (2007-2017). Quasi-Poisson regression analysis with backward selection was used to investigate the relationship between the surgical approach and outcomes of interest.

Among the 664 patients included in the study, the distribution of surgical approaches was as follows: 351 (52.9%) underwent TME via the open approach, 159 (23.9%) via the robotic approach, and 154 (23.2%) via the laparoscopic approach. There were no significant differences in baseline demographics among the three cohorts. The laparoscopic cohort had fewer patients with low rectal cancer (<6 cm from the anal verge) than the robotic and open cohorts (Lap 28.6% versus Rob 59.1% versus Open 45.6%, P = 0.015). Patients who underwent Rob and Lap TME had lower intraoperative blood loss compared with the Open approach (Rob 200 mL [Q1, Q3: 100.0, 300.0] versus Lap 150 mL [Q1, Q3: 75.0, 250.0] versus Open 300 mL [Q1, Q3: 150.0, 600.0], P < 0.001). There was no difference in the operative time (Rob 243 min [Q1, Q3: 203.8, 300.2] versus Lap 241 min [Q1, Q3: 186, 336] versus Open 226 min [Q1, Q3: 178, 315.8], P = 0.309) between the three approaches. Postoperative length of stay was shorter with robotic and laparoscopic approach compared to open approach (Rob 5.0 d [Q1, Q3: 4, 8.2] versus Lap 5 d [Q1, Q3: 4, 8] versus Open 7.0 d [Q1, Q3: 5, 9], P < 0.001). There was no statistically significant difference in the quality of TME between the robotic, laparoscopic, and open approaches (79.2%, 64.9%, and 64.7%, respectively; P = 0.46). The margin positivity rate, a composite of circumferential margin and distal margin, was higher with the robotic and open approaches than with the laparoscopic approach (Rob 8.2% versus Open 6.6% versus Lap 1.9%, P = 0.17), Rob versus Lap (odds ratio 0.21; 95% confidence interval 0.05, 0.83) and Rob versus Open (odds ratio 0.5; 95% confidence interval 0.22, 1.12). There was no difference in long-term survival, including overall survival and recurrence-free survival, between patients who underwent robotic, laparoscopic, or open TME (Figure 1).

In patients undergoing surgery with curative intent for rectal cancer, we did not observe a difference in the quality of TME between the robotic, laparoscopic, or open approaches. Robotic and open TME compared to laparoscopic TME were associated with higher margin positivity rates in our study. This was likely due to the higher percentage of low rectal cancers in the robotic and open cohorts. We also reported no significant differences in overall survival and recurrence-free survival between the aforementioned surgical techniques.