Postoperative Radiotherapy Improves Survival in Stage pT2N0M0 Esophageal Squamous Cell Carcinoma with High Risk of Poor Prognosis

Clinically, some patients with stage pT2N0M0 esophageal squamous cell carcinoma (ESCC) might have poor survival outcomes after Ivor-Lewis esophagectomy. We explored whether adjuvant radiotherapy could improve the prognosis for the patients with high risk of poor clinical outcomes. We screened 326 pT2N0M0 ESCC patients who had complete resection with Ivor-Lewis esophagectomy. The expression profile of Ku80 was examined by immunohistochemistry and validated by Western blotting. Patients with high expression of Ku80 were divided randomly into the adjuvant radiotherapy group and control group. Patients with low expression of Ku80 were enrolled into the negative group. The overall survival (OS) and disease-free survival (DFS) was determined by Kaplan-Meier and log-rank analysis. According to receiver operating characteristics curve analysis of Ku80 expression, 124 patients were enrolled into the negative group, 106 patients into the radiotherapy group, and 106 patients into the control group. Log-rank analysis showed that patients in the control group had worse OS and DFS than those in the negative group (P < 0.001, P < 0.001). There is no difference in OS and DFS of patients between radiotherapy group and negative group (P = 0.166, P = 0.648). Patients in the radiotherapy group had significantly better OS and DFS than those in the control group (P = 0.007, P < 0.001). Multivariate analysis further suggested that adjuvant radiotherapy was an independent prognostic indicator for patients with Ku80 overexpression. In stage pT2N0M0 ESCC, Ku80 can be exploited as a predictor to identify patients with high risk of poor prognosis. Adjuvant radiotherapy could significantly improve survival for the patients with Ku80 overexpression.