Difference in failure patterns of pT3-4N0-3M0 esophageal cancer treated by surgery vs surgery plus radiotherapy

BACKGROUND: There has been no study comparing the difference in the failure patterns between patients with or without postoperative radiotherapy (PORT) after esophagectomy for pT3-4N0-3M0 esophageal squamous cell carcinoma (ESCC). AIM: To investigate the difference in the failure patterns of stage pT3-4N0-3M0 ESCC patients with or without PORT. METHODS: Patients with stage pT3-4N0-3M0 ESCC, who underwent surgery with or without PORT, were enrolled in this study. The primary endpoint was to investigate the difference in the failure patterns between patients with or without PORT after esophagectomy. The secondary endpoint was to estimate whether patients with stage pT3-4 ESCC could achieve a disease-free survival (DFS) advantage after receiving adjuvant PORT. Statistical analyses were performed by the Kaplan-Meier method, Cox regression model, and Chi-squared test or Fisher’s exact test. RESULTS: In total, 230 patients with stage pT3-4N0-3M0 ESCC were included in this study. Fifty-six patients who received PORT were screened from a prospective cohort (S + R arm). And 174 patients involving surgery alone were retrospectively selected from July 2006 to October 2014 (S arm). There were no significant differences in the clinical or pathological characteristics of patients between the two arms, except for tumor location (P = 0.031). The failure patterns between the two arms were significantly different (P < 0.001). Patients in the S arm had a significantly higher proportion of locoregional recurrence and a lower proportion of distant metastasis than those in the S + R arm (92.0% vs 35.7%, P < 0.001 and 19.0% vs 75.0%, P < 0.001, respectively). The difference in the median DFS between the two arms was statistically significant (12.7 vs 8 mo, P = 0.048). Univariate analysis and multivariate analysis both demonstrated that the number of lymph node metastases ≥ 3 (HR = 0.572, 95%CI: 0.430-0.762, P < 0.001) was an independent poor prognostic factor for DFS in patients with stage pT3-4N0-3M0 ESCC. CONCLUSION: PORT could improve DFS and local control of patients with stage pT3-4N0-3M0 ESCC. However, further studies need to be conducted to control hematogenous metastasis after PORT.