Robotic surgery has been taken as a new modality to surpass the technical limitations of conventional surgery. In this retrospective study, we aim to compare the short- and long-term oncologic outcomes in patients with rectal cancer who receive robotic surgery vs. laparoscopic surgery. Interestingly, we found patients underwent robotic surgery had lower tumor location and higher clinical T stage, compared to those receiving laparoscopic surgery. Operation on patients with lower tumor location and higher clinical T stage usually means more challenging and requires higher surgical techniques than those without, indicating robotic surgery may have advantages in rectal surgery on more sophisticated cases due to its better visualization and a finer and dexterous pelvic dissection within a narrow pelvic cavity. Importantly, time to 1st gas passing and 1st soft diet and the length of hospital stay were significantly shorter in the robot group, indicating that robotic surgery might avail to enhance recovery after surgery. No significant difference was observed with respect to the most of postoperative short- or long-term adverse events, while the incidence of urinary retention is significantly decreased in patients with robotic surgery, compared to those with laparoscopic surgery, which also indicated the superiority of robotic surgery to laparoscopy on an easier identification of the inferior hypogastric plexus.
Postoperative pathological parameters that can measure the quality of rectal surgery are CRM positivity and number of harvested lymph nodes of the resected specimen, which both has no significant difference between robotic and laparoscopic surgical approach. CRM involvement rate in this study was 1.3% vs. 0 between the Robot and Laparoscopy group, which was comparable with the previous studies (0%-16%)[5, 7, 12, 16]. In the Robot group, there were totally 4 cases (4/317) with positive CRM, and local recurrence occurred in 2 cases with positive CRM. However, in the laparoscopy group, there were no cases with positive CRM, and local recurrence occurred in 12 cases (12/224) with negative CRM. A positive CRM did not seem to be translated to local recurrence. That CRM was not a prognostic factor for predicting survival by multivariate analysis could support this finding.
Cumulative OS and DFS, the gold prognosticator, indicates the long-term oncologic outcomes, and also reflect the superiority of surgical technique in cancer resection. Few previous studies showed the cumulative OS and DFS between the Robot and Laparoscopy group. Baek, et al reported that the 3-year OS and DFS were 96.2% and 73.7% respectively, for patients with stages I-III rectal cancer who underwent robotic surgery from the 1-arm case series study. Pigazzi et al presented similar 3-year oncologic results of robotic rectal cancer surgery with data from three different centers. Baek, et al also compared the short- and long-term outcomes between robotic and laparoscopic ultra low anterior resection and coloanal anastomosis, and reported no difference was shown in local recurrence, 3-year OS, or DFS between the two groups. Park, et al reported that the 5-year OS was 92.8% in robotic surgery, and 93.5% in laparoscopic surgical procedures, while the 5-year DFS was 81.9% and 78.7%, respectively. Here, we presented that the 1-, 3- and 5-year OS was 96.6-, 88.4-, 87.3% in the Robot group and 96.8-, 87.4-, 77.7% in the Laparoscopy group. The 1-, 3- and 5-year DFS was 98.6-, 79.1-, 72.5% in the Robot group and 95.4-, 86.5-, 80.4% in the Laparoscopy group.
Robotic surgery requires a surgeon to take a long time to learn to adapt to new surgical techniques, such as controlling consoles, manipulating new instruments, and cooperation with the surgical team[20, 21, 22]. Our team has adequate experience in robotic surgery, with nearly 200 cases of robotic surgery on rectal cancer per year, and that is why our study demonstrated the operation time and intraoperative bleeding were both significantly less than that of laparoscopy. The high cost of robotic surgery is also a problem, which make it cannot be widely recommended for patients. Nevertheless, the robotic system is continuously being improved and more advanced technologies will be developed, such as a novel Senhance® robotic system (TransEnterix Surgical Inc., Morrisville, NC, USA), which has been proved to be feasible and safe in general surgery, gynecology, and urology. We suppose the cost of robotic system will become more and more acceptable
In conclusion, among patients with rectal cancer, the robotic surgery was not associated with an improved survival compared to the laparoscopic surgery, however, the robot surgery is a safe and feasible surgical procedure, especially for some sophisticated cases with lower tumor location. Further prospective randomized trials are needed to clarify these findings.