Quality of total mesorectal excision and depth of circumferential resection margin in rectal cancer: a matched comparison of the first 20 robotic cases

Abstract

Aim: There are concerns about the impact of robotic proctectomy on the quality of total mesorectal excision (TME) and the impact of laparoscopic proctectomy on the depth of the circumferential resection margin (CRM). The aim of this study was to compare the first 20 consecutive robotic proctectomies performed in our unit with matched series of open and laparoscopic proctocolectomy performed by the same surgeon.

Method: Data on the first 20 consecutive patients treated with robotic proctectomy for rectal cancer, <12 cm from the anal verge, by the senior author (RB) were extracted from a prospectively maintained database. Groups of patients treated with open and laparoscopic proctectomy, matched for age, gender and body mass index (BMI) with those undergoing robotic proctectomy, were selected. The quality of the TME was judged as complete, nearly complete or incomplete. CRM clearance was reported in millimetres. Physiological parameters and operative severity were assessed.

Results: Age (P = 0.619), Physiological and Operative Severity Score for the Enumeration of Morbidity and Mortality (POSSUM) score (P = 0.657), operative severity score (P = 0.977), predicted mortality (P = 0.758), comorbidities (P = 0.427), previous abdominal surgery (P = 0.941), tumour height (P = 0.912), location (P = 0.876), stage (P = 0.984), neoadjuvant chemoradiation (P = 0.625), operating time (P = 0.066), blood loss (P = 0.356), ileostomy (P = 0.934), conversion (P = 0.362), resection type (P = 1.000), flatus (P = 0.437), diet (P = 0.439), length of hospital stay (P = 0.978), complications (P = 0.671), reoperations (P = 0.804), reinterventions (P = 0.612), readmissions (P = 0.349), tumour size (P = 0.542; P = 0.532; P = 0.238), distal margin (P = 0.790), nodes harvested (P = 0.338) and pathology stage (P = 0.623) did not differ among the three groups. The quality of TME showed a trend to be lower following robotic surgery, although this was not statistically significant [open 95/5/15 (complete/nearly complete/incompete) vs laparoscopic 95/5/15 vs robotic 80/5/15; P = 0.235], but the degree of clearance at the CRM was significantly greater in robotic patients [open 8 (0-30) mm vs laparoscopic 4 (0-30) mm vs robotic 10.5 (1-30) mm; P = 0.02].

Conclusion: The study reports no statistically significant difference between open and laparoscopic techniques in the quality of TME during the learning curve of robotic proctectomy for rectal cancer and demonstrates an improved CRM.

Keywords: Rectal cancer; circumferential resection margin; laparoscopic surgery; learning curve; total mesorectal excision.