Comparing pathologic outcomes for robotic versus laparoscopic Surgery in rectal cancer resection: a propensity adjusted analysis of 7616 patients.

BACKGROUND: Margin negative resection of rectal cancer with minimally invasive techniques remains technically challenging. Robotic surgery has potential advantages over traditional laparoscopy. We hypothesize that the difference in the rate of negative margin status will be < 6% between laparoscopic and robotic approach. METHODS: The National Cancer Database (2010-2014) was queried for adults with locally advanced rectal cancer who underwent neoadjuvant chemoradiation and curative resection to conduct an observational retrospective cohort study of a prospectively maintained database. Patients were grouped by either robotic (ROB) or laparoscopic (LAP) approach in an intent-to-treat analysis. Primary outcome was negative margin status, defined as a composite of circumferential resection margin and distal margin. Secondary outcomes included length of stay (LOS), readmission, 90-day mortality, and overall survival. RESULTS: 7616 patients with locally advanced rectal cancer who underwent minimally invasive resection were identified. 2472 (32%) underwent attempted robotic approach. The overall conversion rate was 13% and was increased in the laparoscopic group [LAP: 15% vs. ROB: 8%; OR 0.47; 95% CI (0.39, 0.57)]. Differences in margin negative resection rate were within the prespecified range of practical equivalence (LAP: 93% vs.: ROB 94%; 95% CI (0.69, 1.06); [Formula: see text] = 1). For secondary outcomes, there was no difference in 30-day readmission [LAP: 9% vs.: ROB 8%; 95% CI (0.84, 1.24)] and 90-day mortality [LAP: 1% vs.: ROB 1%; 95% CI (0.38, 1.24)]. While the median LOS was 5 days in both groups, the mean LOS was 0.6 (95% CI: 0.24, 0.89) days shorter in the robotic group. CONCLUSION: This robust analysis supports either robotic or laparoscopic approach for resection of locally advanced rectal cancer from a margin perspective. Both have similar readmission and 5-year overall survival rates. Patients undergoing robotic surgery have a 0.6-day decrease in LOS and decreased conversion rate.