Comparison of the short-term efficacy of two types of robotic total mesorectal excision for rectal cancer.

BACKGROUND The advantages and disadvantages of robotic technology compared with conventional surgery for low rectal cancer have been discussed extensively. However, a few studies on the efficacy of total mesorectal excision (TME) with different robotic technologies have been reported. The aim of this study was to evaluate the efficacy of two types of robot-assisted TME (R-TME) compared with laparoscopic TME (L-TME). METHODS A prospective comparative study was conducted comparing da Vinci R-TME, Micro Hand S R-TME, and L-TME for rectal cancer. This study was registered with "Clinicaltrials.gov" (ID: NCT02752698) and approved by the Association for the Accreditation of Human Research Protection Program (AAHRPP) (Project number: T16007). Between January 2017 and May 2019, patients with rectal cancer (cT1-3NxM0) were prospectively registered in the Third Xiangya Hospital. The integrity of the TME sample served as the primary outcome. Secondary outcomes included the involvement of the circumferential and distal resection margins (CRM and DRM), number of lymph nodes retrieved, blood loss, operative time, conversion rate, comprehensive complication index score, the International Prostate Symptom score, the International Index of Erectile Function, and the Female Sexual Function Index. RESULTS Of 134 patients with rectal cancer (74 males, mean age [SD] 59.1 ± 8.27 years), 46 patients underwent laparoscopic TME, 45 patients underwent da Vinci R-TME, and 43 patients underwent Micro Hand S R-TME. There were no differences in results between the two types of R-TME. Compared with laparoscopic TME, significant reductions in blood loss (median 65.50 ml da Vinci; median 66.54 ml Micro Hand S vs median 95.04 ml L-TME p = 0.037 and p = 0.041, respectively) and conversion rate (2.2% da Vinci; 2.3% Micro Hand S vs 6.8% L-TME p = 0,040 for the comparison daVinci L-TME and p = 0.038 for the comparison Micro Hand S vs. L-TME) with da Vinci Si and Micro Hand S R-TME were noted, and significant increases in operation time (230.05 min da Vinci; 235.03 min Micro Hand S vs. 205.53 min L-TME p = 0.045 and p = 0.043, respectively) was observed. Additionally, more patients underwent TME with sphincter-preserving methods in the two R-TME groups based on the type of operation (da Vinci 97.7%; Micro Hand S 97.9% vs. L-TME 82% resulting in  p = 0.033 for the comparison daVinci L-TME and p = 0.035 for the comparison Micro Hand S vs. L-TME). In comparison with L-TME, there was a larger number of lymph nodes retrieved (da Vinci mean 17.54; Micro Hand S mean 17.32 vs. L-TME mean 14.96 p = 0.031 for the comparison daVinci L-TME and p = 0.033 for the comparison Micro Hand S vs L-TME) and less blood loss (da Vinci mean 65.50 ml; Micro Hand S mean 66.54 ml vs. L-TME mean 95.04 ml, p = 0.037 for the comparison daVinci L-TME and p = 0.041 for the comparison Micro Hand S vs. L-TME), and incidence of severe postoperative complications was similar among three TME groups except for the earlier recovery of urogenital function (mean IPSS score da Vinci 7.73±1.35; Micro Hand S7.75±1.47 vs L-TME 14.26±1.41 p<0.001 for the comparison da Vinci L-TME and p<0.001 for the comparison Microhand S vs L-TME) in the two R-TME groups. CONCLUSIONS In our study, compared with laparoscopic surgery, da Vinci or Micro Hand R-TME exhibited similar superiority in the quality of oncologic resection, postoperative morbidity, and recovery of postoperative function.