Efficacy of different postoperative adjuvant therapy strategies for stage II/III thoracic esophageal squamous cell carcinoma

Abstract

Objective To evaluate the efficacy and adverse reactions of postoperative chemoradiotherapy (S+ CRT) and postoperative radiotherapy (S+ RT) for stage Ⅱ/Ⅲ thoracic esophageal squamous cell carcinoma. Methods Clinical data were collected from 215 patients with stage Ⅱ/Ⅲ thoracic esophageal squamous cell carcinoma who received radical resection and postoperative adjuvant radiotherapy or chemoradiotherapy from 2007 to 2010. Survival rates were calculated by the Kaplan-Meier method and analyzed by the log-rank test. Univariate and multivariate analyses were made by the log-rank test and Cox proportional model, respectively. Results The data were comparable between the S+ CRT group and the S+ RT group (P=0.055-0.988). The numbers of patients who received 1-, 3-, and 5-year follow-up were 203, 133, and 108, respectively. In all the patients, the 1-, 3-, and 5-year overall survival (OS) rates were 94.0%, 61.4%, and 49.3%, respectively, and the 1-, 3-, and 5-year disease-free survival (DFS) rates were 74.9%, 53.5%, 46.7%, respectively. Preoperative mediastinal lymph node enlargement on computed tomography (CT), the degree of adhesion of esophageal lesions to peripheral tissues during surgery, pathological N staging, vascular tumor thrombus, the number of positive lymph nodes, and treatment strategy were independent prognostic factors for OS (P=0.000-0.034). Preoperative mediastinal lymph node enlargement revealed on CT, the degree of adhesion of esophageal lesions to peripheral tissues during surgery, incomplete removal of tumor from the esophagus, the number of positive lymph nodes, and treatment strategy were independent prognostic factors for DFS (P=0.000-0.049). The S+ CRT group had significantly improved OS and DFS rates than the S+ RT group (P=0.002, 0.002). The result of stratified analysis showed that for the patients with stage Ⅱ disease and those with stage N1 disease, the S+ CRT group had significantly improved OS and DFS rates than the S+ RT group (P=0.041, 0.001, 0.021, 0.024). The S+ CRT group had significantly higher incidence rates of grade ≥2 radiation-induced gastritis and marrow suppression than the S+ RT group (P=0.000, 0.015). Conclusions Both S+ CRT and S+ RT achieve satisfactory treatment outcomes in patients with stage Ⅱ/Ⅲ thoracic esophageal squamous cell carcinoma. Compared with S+ RT, S+ CRT can significantly improve the OS and DFS in patients with stage Ⅱ or N1 disease; S+ CRT causes more severe but tolerable adverse reactions. Prospective randomized phase Ⅲ clinical studies are still required to confirm the final conclusions. Key words: Esophageal neoplasms/surgery; Esophageal neoplasms/postoperative radiotherapy; Esophageal neoplasms/postoperative chemoradiotherapy; Prognosis