The volume-outcome relationship in robotic protectectomy: does center volume matter? Results of a national cohort study.

Abstract

Utilization of robotic proctectomy (RP) for rectal cancer has steadily increased since the inception of robotic surgery in 2002. Randomized control trials evaluating the safety of RP are in process to better understand the role of robotic assistance in proctectomy. This study aimed to characterize the trends in the use of RP for rectal cancer, and to compare oncologic outcomes with center-level RP volume. 8107 patients with rectal adenocarcinoma who underwent RP were identified in the National Cancer Database (2010-2015). Logistic regression was used to evaluate associations between center-level volume and conversion to open proctectomy, margin status, lymph node yield, 30- and 90-day post-operative mortality, and overall survival. The utilization of RP increased from 2010 to 2015. On multivariate regression, lower center-level volume of RP was associated with significantly higher rates of conversion to open, positive margins, inadequate lymph node harvest (≥ 12), and lower overall survival. The present study was limited by its retrospective design and lack of information regarding disease-specific survival. This series suggests a volume-outcome relationship association; patients who have robot-assisted proctectomies performed at low-volume centers are more likely to have poorer overall survival, positive margins, inadequate lymph node harvest, and require conversion to open surgery. While these data demonstrate the increased adoption of robot-assisted proctectomy, an understanding of the appropriateness of this intervention is still lacking. As with any new intervention, further information from ongoing randomized controlled trials is needed to better clarify the role of RP in order to optimize patient outcomes.