Adjuvant Chemotherapy and Dose Escalation in Definitive Concurrent Chemoradiotherapy for Esophageal Squamous Cell Carcinoma

Background/Aim: To validate the effect of treatment intensification on survival in esophageal squamous cell carcinoma (ESCC) patients undergoing definitive concurrent chemoradiotherapy (dCCRT). Patients and Methods: We reviewed the medical records of 73 ESCC patients who underwent dCCRT between 2006 and 2017 in 3 institutions. Results: The median follow-up time was 13.3 months. The median overall survival ( OS) and locoregional recurrence-free survival (LRFS) were 13.3 and 11.2 months, respectively. The median radiotherapy dose was 55.8 Gy, and the median biologically effective dose (BED) was 65.8 Gy. Chemotherapy was given in all patients during dCCRT, and adjuvant chemotherapy was administered in 56 patients (76.7%). Adjuvant chemotherapy improved OS (3-year, 24.2% vs. 11.8%, p=0.004). Higher BED >= 70 Gy improved LRFS (3-year, 41.7% vs. 23.6%, p=0.035). Conclusion: The addition of chemotherapy after dCCRT improves OS. A higher radiotherapy dose improved LRFS, but not OS. Adjuvant chemotherapy should be considered after dCCRT for better outcomes.