Analysis of clinical outcomes and prognostic factors in patients treated with definitive chemoradiotherapy for oesophageal squamous cell carcinoma

As patients receiving definitive chemoradiotherapy (dCRT) for oesophageal squamous cell carcinoma (ESCC) are heterogeneous, we aimed to identify prognostic factors and failure patterns after dCRT. From 2006 to 2015, 327 patients who received dCRT for ESCC were reviewed. Treatment response to dCRT was evaluated based on EORTC‐PET criteria with endoscopy and CT results. After dCRT, 296 patients (90.5%) achieved disease stabilisation, with 132 cases of complete response (CR) (40.4%), 158 of partial response (PR) (48.3%) and 6 of stable disease (SD) (1.8%); 31 patients (9.5%) had progressive disease (PD). Median overall survival (OS) from response evaluation was 24.0 months in the overall population. Post‐treatment clinical response was the most significant prognostic factor for OS in the multivariate analysis (median OS, 65.0 months for CR, 17.3 months for PR, 4.4 months for SD and 4.0 months for PD; p < 0.0001). Median progression‐free survival (PFS) in 296 patients who achieved disease stabilisation was 13.1 months, and only clinical response was a significant factor in the multivariate analysis. The median PFS of CR, PR and SD patients were 36.9, 9.2 and 2.8 months, respectively (p < 0.0001). The clinical response was also significantly associated with the predominant failure pattern (locoregional failure [81.6%] in the initial non‐PD group vs. distant metastasis [87.1%] in the initial PD group [p < 0.0001]). In conclusion, definitive chemoradiotherapy‐treated ESCC patients showed highly different prognoses after treatment especially according to the clinical response to chemoradiotherapy.