Definitive Concurrent Chemoradiotherapy in Esophageal Squamous Cell Carcinoma: High Dose versus Standard Dose Radiation Therapy

Abstract

Purpose: To analyze the treatment results and compare overall survival rate after definitive concurrent chemoradiotherapy (CCRT) with different doses of radiotherapy for esophageal squamous cell carcinoma (ESCC) in a retrospective study. Materials and Methods: This study included 109 patients with histologically confirmed ESCC at Taipei Veterans General Hospital between January 2007 and December 2010. The median age at diagnosis of the patients was 62 years old (range, 34-89 years). Patients who were clinically staged as T2-4, N0-1, M0-1, stage II-IV ESCC received definitive CCRT as the primary treatment, with radiotherapy at 1.8-2.0 Gy per fraction and concurrent infusional cisplatin-based chemotherapy for 1-2 cycles. Radiotherapy was delivered by three-dimensional conformal radiation therapy (3DCRT) or intensity modulated radiation therapy (IMRT) technique, with a median dose of 56 Gy (range, 45-70 Gy). The overall survival (OS) rates and local recurrence free survival (LRFS) rates were compared between high radiation dose (56-70 Gy, n= 55) group and standard radiation dose (45-55.8 Gy, n= 54) group. Survival analysis was done with the Kaplan-Meier method and Cox regression model.Results: Two-year overall survival rate of the high-dose and standard-dose group was 38.0% and 23.2%, respectively. The 2-year OS rate of stage II, III, and IV was 57.9%, 32.8%, and 20.1%, respectively. Univariate analysis revealed that high dose radiation (≧56 Gy), T classification, M classification, and clinical stage significantly affected overall survival (p= 0.013, 0.016, 0.012, and 0.010, respectively). Multivariate analysis showed that high dose radiation ≧56 Gy (p= 0.030) and clinical stage II-III (p= 0.015) were significant predictors of better OS. In the univariate and multivariate analyses of the patients with M0 disease (n= 49), high dose radiation also has a remarkable impact on LRFS (p= 0.020, 0.003, respectively). Conclusion: Our study showed that higher radiation dose (≧56 Gy) significantly improved OS and LRFS in patients with unresectable ESCC who underwent definitive CCRT using 3DCRT or IMRT techniques. Further randomized clinical studies are required to clarify the benefits and side effects of escalated radiation dose in the setting of modern conformal radiotherapy techniques.