A Single-Arm Confirmatory Study of Definitive Chemoradiation Therapy Including Salvage Treatment for Clinical Stage II/III Esophageal Squamous Cell Carcinoma (JCOG0909 Study)

Definitive chemoradiotherapy (CRT) is the standard treatment for patients with locally advanced esophageal cancer (EC) who refuse surgery as the initial therapy. However, poor survival, a high incidence of late toxicities, and severe complications after salvage surgery remain issues to be resolved. This single-arm multicenter trial (JCOG0909) aimed to confirm the efficacy of CRT modifications, including salvage treatment for reducing CRT-related toxicities and facilitating salvage treatment for improved survival.Patients with clinical stage II/III EC (International Union Against Cancer sixth edition, non-T4) were eligible. Chemotherapy comprised cisplatin (75 mg/m2 on days 1 and 29) and 5-fluorouracil (1000 mg/m2/d on days 1-4 and 29-32). Radiation therapy was administered at a total dose of 50.4 Gy. Good responders received 1 to 2 additional cycles of chemotherapy. For residual or recurrent disease, salvage endoscopic resection or salvage surgery was performed based on specific criteria. The primary endpoint was 3-year overall survival (OS). The calculated sample size was 95 patients, with a 1-sided alpha of 5% and a power of 80%. The expected and threshold 3-year OS were 55% and 42%, respectively.Overall, 96 patients were enrolled, and 94 were included in the efficacy analysis. A complete response was achieved in 55 patients (59%). Salvage endoscopic resection and salvage surgery were performed in 5 (5%) and 25 patients (27%), respectively. R0 resection by salvage surgery was achieved in 19 patients (76%). Five patients (20%) showed grade 3 or 4 early operative complications, and 9 patients (9.6%) showed grade 3 late toxicities during the long-term follow-up. The 3-year OS was 74.2% (90% confidence interval, 65.9%-80.8%).The combination of definitive CRT and salvage treatment has lower CRT-related toxicities and yields good OS, thus making it a promising novel treatment option for patients with locally advanced EC.