Development and Validation of the Optimal Circumferential Resection Margin in Pathological T3 Esophageal Cancer: A Multicenter, Retrospective Study.

BACKGROUND: The clinical significance of circumferential resection margin (CRM) in esophageal squamous cell carcinoma (ESCC) remains unclear. Optimal CRM for predicting the recurrence of pathological T3 ESCC was investigated. METHODS: Seventy-three patients were retrospectively investigated in the development cohort. Patients were divided into CRM-negative and CRM-positive groups, and clinicopathological factors and survival outcomes were compared between the groups. The cutoff value was validated in another validation cohort (n = 99). RESULTS: Receiver operating characteristic analysis in the development cohort showed the cutoff value of CRM was 600 µm. In the validation cohort, patients in the CRM-positive group showed a significantly higher rate of locoregional recurrence (p = 0.006) and worse recurrence-free survival (RFS) (p < 0.001) than those in the CRM-negative group. Multivariate analysis identified positive CRM as an independent predictive factor for poor RFS (hazard ratio, 2.695; 95% confidence interval, 1.492-4.867; p = 0.001). The predictive value of our criteria of positive CRM for RFS was higher than that of the Royal College of Pathologists (RCP) and the College of American Pathologists (CAP) criteria. Stratified analysis in the neoadjuvant chemotherapy groups also revealed that the rate of locoregional recurrence was higher in the CRM-positive group than in the CRM-negative group both in the pathological N0 and N1-3 subgroups. CONCLUSIONS: CRM of 600 µm can be the optimal cutoff value rather than the RCP and CAP criteria for predicting locoregional recurrence after esophagectomy. These results may support the impact of perioperative locoregional control of locally advanced ESCC.