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

Abstract

Purpose: 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.

Methods and materials: 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.

Results: 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%).

Conclusion: 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.