Comparison of short-term outcome between robotic-assisted and laparoscopic total mesorectal excision for mid to low rectal cancer

Abstract

Background: Laparoscopic total mesorectal excision (TME) is a technically challenging procedure. With its three dimensional vision, flexible instruments and powerful retraction, surgical robotic system may serve to be a better tool in performing complex procedures inside a confined bony pelvis. Yet there is a concern for increase in operative cost. This study aim to review and compare the short-term results of laparoscopic TME (L-TME) and robotic-assisted TME (R-TME) in a single centre. Methods: This study is based on a prospectively collected database of patients with mid to low rectal cancer undergoing either L-TME or R-TME from January 2006 to September 2014. Data on patient demographics, intraoperative parameters and short-term outcome were collected. All patients with cancer of rectum within 12cm from the anal verge (AV) were included. Those with multi-organ resections were excluded. Results: During this period, there were a total of 137 and 164 consecutive patients undergoing L-TME and R-TME respectively. The mean age was 66.4±13.2 and 65.7±10.9 years for L-TME and R-TME. The mean tumour distance from AV was 69.3±29.9 and 68.0±29.9mm for L-TME and R-TME. There was no difference between the demographics in terms of sex, American Society of Anesthesiologist score, preoperative radiation and tumour staging. The mean operating time for R-TME was significantly longer, 271.5±66.5 vs 229.2±60.7 min, p=0.00. Difference in terms of blood loss was not significant. Conversion rate of L-TME and R-TME was 2.9% and 1.8%, p=0.71. Sphincter-saving procedure was done in 91.2% of L-TME and 92.1% of R-TME. Mean hospital stay was 8.5±9.4 and 8.0±7.4 days for L-TME and R-TME, p=0.60. Mean distal margin of L-TME and R-TME was 33.4±15.2mm and 31.3±15.9mm, p-=0.25. Positive circumferential radial margin was found in 8.0% of L-TME and 4.9% of R-TME, p=0.34. Complications rate of L-TME and R-TME was 17.5% and 14.0%. In particular, there was a significantly higher percentage of postoperative urinary retentions in L-TME 11.7% vs 4.3%, p=0.02, RR 2.74, 95% CI 1.16–6.46. 30 day mortally L-TME and R-TME was 1.5% and 1.2%, p=0.61. Conclusion: In the treatment of mid to low rectal cancer, robotic-assisted and laparoscopic total mesorectal excision has comparable short–term outcome. Robotic-assisted approach, however, might offer better functional outcome as a result of autonomic nerve preservation.