Prognostic Value of the Circumferential Resection Margin After Curative Surgery for Rectal Cancer: A Multicenter Propensity Score-Matched Analysis

BACKGROUND: Recently, positive circumferential resection margin has been found to be an indicator of advanced disease with a high risk of distant recurrence rather than local recurrence. OBJECTIVE: The study aimed to analyze the prognostic impact of the circumferential resection margin on longterm oncological outcomes in patients with rectal cancer. DESIGN: This was a multicenter, propensity score-matched (2:1) analysis comparing the positive and negative circumferential resection margins. SETTINGS: The study was conducted at 5 high-volume centers in Spain. PATIENTS: Patients who underwent total mesorectal excision with curative intent for middle-low rectal cancer between 2006 and 2014 were included. MAIN OUTCOME MEASURES: The main outcomes were local recurrence, distant recurrence, overall survival, and disease-free survival. RESULTS: The unmatched initial cohort consisted of 1599 patients, of whom 4.9% had a positive circumferential resection margin. After matching, 234 patients were included (156 with a negative circumferential margin and 78 with a positive circumferential margin). The median follow-up period was 52.5 (22.0-69.5) months. Local recurrence was significantly higher in patients with a positive circumferential margin (33.3% vs 11.5%; p < 0.001). Distant recurrence was similar in both groups (46.2% vs 42.3%; p = 0.651). There were no statistically significant differences in 5-year overall survival (48.6% vs 43.6%; p = 0.14). Disease-free survival was lower in patients with a positive circumferential margin (36.1% vs 52.3%; p = 0.026). LIMITATIONS: This study was limited by its retrospective design. The different neoadjuvant treatment options were not included in the propensity score. CONCLUSIONS: The positive circumferential resection margin was associated with a higher local recurrence rate and worse disease-free survival in comparison with the negative circumferential resection margin. However, the positive circumferential resection margin was not a prognostic indicator of distant recurrence and overall survival. See Video Abstract at http://links.lww.com/DCR/ B950.