Laparoscopic Versus Robot-Assisted Low Anterior Resection With Mesorectal Excision For Rectal Cancer (2014–2021): A Propensity-Weighted Multicentre Cohort Study of Long-term Oncological Outcomes (RESOLUTION)

BACKGROUND: Robot-assisted total mesorectal excision was introduced to overcome several technical constraints associated with conventional laparoscopic total mesorectal excision in rectal cancer surgery. Nevertheless, data on long-term oncological outcomes remain limited. OBJECTIVE: This study compared long-term oncological outcomes between robot-assisted total mesorectal excision and laparoscopic total mesorectal excision for rectal cancer. DESIGN: Retrospective, multicenter, international cohort study employing inverse probability of treatment weighting to minimize confounding. SETTINGS: Expert centers specialized in colorectal cancer for their respective surgical approach across the United Kingdom, the Netherlands, and France. PATIENTS: There were 1077 rectal cancer patients with at least 3 years of follow-up who underwent either laparoscopic or robot-assisted total mesorectal excision from 2014 to 2021. MAIN OUTCOME MEASURES: The primary outcome was 3-year disease-free survival. Secondary outcomes included 3-year local recurrence, 3-year systemic recurrence, and three-year overall survival. RESULTS: A total of 435.8 laparoscopic and 637.4 robot-assisted cases were analyzed after weighting. More robot-assisted cases were graded as complete total mesorectal excision than in the laparoscopic group (76.5% vs. 87.5%, p < 0.001), but without significant differences in circumferential resection margin positivity, conversion rates, or postoperative complications. Robot-assisted surgery led to higher restorative low anterior resection rates (93.2% vs 80.6%, p < 0.001), and less stoma creation (69.1% vs 80.9%, p < 0.001). No significant differences were found in 3-year disease-free survival (75.1% vs 75.2%, HR 1.04, CI: 0.80-1.34), overall survival (81.6% vs 81.7%, HR 1.14, CI: 0.80-1.61), local recurrence (3.7% vs 3.0%, HR 0.89, CI 0.45-1.80), or systemic recurrence (15.1% vs 15.3%, HR 0.97, CI: 0.69-1.34). LIMITATIONS: Because this is an observational propensity-weighted analysis, these results should be interpreted as an absence of observed differences rather than evidence of equivalence, and residual confounding (including temporal and center-level factors) may remain. CONCLUSION: Robot-assisted surgery was associated with improved pathological specimen grade and more restorative procedures, while no statistically significant differences were observed in 3-year oncological outcomes. See Video Abstract.Clinical study registry: https://www.isrctn.com/ISRCTN75281193.