Efficacy of postoperative radiotherapy in esophageal squamous cell carcinoma patients with positive circumferential resection margin.

BACKGROUND The significance of postoperative radiotherapy for residual disease after esophageal cancer surgery remains controversial. The purpose of this study was to elucidate the efficacy of postoperative radiotherapy in esophageal squamous cell carcinoma (ESCC) patients with positive circumferential resection margin (CRM). METHODS We retrospectively analyzed data from 1190 patients who underwent esophagectomy for ESCC at our hospital from 2005 to 2018, of whom 61 (5.1%) patients were diagnosed with positive CRM of ESCC. Overall survival (OS), progression-specific survival (PSS), local progression-specific survival (LPSS), and clinicopathological factors were compared between patients with and without postoperative radiotherapy. The efficacy of additional radiotherapy on patient outcomes was evaluated. RESULTS Among the 61 patients analyzed, 29 (47.5%) underwent radiotherapy (RT group) and 32 (52.5%) did not (NRT group). In the RT group, 22 patients (75.9%) received radiotherapy and 7 patients (24.1%) received chemoradiotherapy. The RT group included younger patients, a greater number of upper-esophageal tumors, and a greater rate of R2 resections than the NRT group. The LPSS and PSS of the RT group were significantly better than those of the NRT group (P = 0.007, P < 0.001, respectively). In multivariate analysis, postoperative radiotherapy was an independent factor for LPSS [P < 0.001; hazard ratio (HR) 0.17; 95% confidence interval (CI) 0.06-0.46] and PSS (P < 0.001; HR 0.31; 95% CI 0.16-0.60). CONCLUSIONS Postoperative radiotherapy contributed to the control of residual tumor and was significantly associated with better LPSS and PSS among patients with positive CRM after esophagectomy for ESCC.