Outcomes of concurrent chemoradiotherapy versus chemotherapy alone for stage IV esophageal squamous cell carcinoma: a retrospective controlled study

Background: The purpose of this study is to compare the efficacy and safety of concurrent chemoradiotherapy (CCRT) versus chemotherapy alone for patients with stage IV esophageal squamous cell carcinoma (ESCC). Methods: Eligible patients were retrospectively enrolled at the authors's institution from January 2010 to October 2015. Of the 141 patients enrolled, 55 (39.0%) received CCRT and 86 (61.0%) received chemotherapy alone. The outcomes and adverse events (AEs) were compared between the two groups. Results: The baseline clinical characteristics of the two groups were similar. However, the CCRT group showed a significantly better primary tumor objective response rate (ORR) than that of the chemotherapy group (74.5% versus 45.3%, p = 0.001). The 1-year, 2-year, 3-year overall survival (OS) rates and median OS were 58.0% versus 43.0%, 25.5% versus 14.0%, 10.7% versus 4.7%, and 14 months versus 11months for patients treated with CCRT or chemotherapy, respectively (p = 0.007). The 1-year and median progression-free survival (PFS) were 29.8% versus 14.9% and 8 months versus 6 months (p = 0.005). Multivariate analysis identified CCRT (p = 0.013) and solitary metastasis (p = 0.037) as independent factors for greater OS. The frequency of leucocytopenia (grade 3 or higher) was significantly higher in the CCRT group than in the chemotherapy-alone group (p = 0.040), whereas the rates of other AEs did not differ. Conclusions: In this study, it is suggested that CCRT is more effective than chemotherapy alone for stage IV ESCC, yielding better primary responses and survival outcomes with tolerable side effects.