Optimizing Organ-Preservation Strategies Through Chemotherapy-Based Selection in Esophageal Squamous Cell Carcinoma: Results From the CROC Multi-Institutional Phase 2 Clinical Trial

Abstract

Purpose: This study aimed to assess the viability of definitive chemoradiotherapy (dCRT) as an organ-preservation strategy for remarkable responders who were downstaged to stage IA after receiving induction chemotherapy for resectable esophageal squamous cell carcinoma (ESCC).

Methods and materials: Chemotherapy-naïve patients with resectable ESCC (stage IB-III, Union for International Cancer Control, International Cancer Control seventh edition) were eligible for the study. All patients received 3 cycles of docetaxel, cisplatin, and 5-FU (DCF) therapy (docetaxel 75 mg/m² on day 1, cisplatin 75 mg/m² on day 1, and 5-fluorouracil [5-FU] 750 mg/m² on days 1-5, repeated every 3 weeks). Remarkable response was defined as a reduction in the tumor to T1, metastatic lymph nodes <1 cm on the short axis, and downstaging to stage IA after 3 cycles of DCF therapy. Remarkable responders then underwent dCRT, which included 2 courses of cisplatin 75 mg/m² and 5-FU 1000 mg/m² on days 1 to 4, repeated every 4 weeks, along with 50.4 Gy of concurrent radiation therapy. The primary endpoint was 1-year progression-free survival in remarkable responders following DCF therapy and subsequent dCRT. Secondary endpoints included 3-year overall survival (OS) and esophagectomy-free survival.

Results: Of the 92 patients registered, 90 were analyzed. A remarkable response to 3 courses of DCF therapy was observed in 58.4% of patients. Among these responders, 89.8% achieved a complete response after dCRT. During the median follow-up period of 33 months (range, 1-85 months), the 1-year progression-free survival was 89.8% (95% confidence interval [CI], 77.2%-95.6%, primary endpoint), and the 3-year OS was 83.7%. The 3-year OS and esophagectomy-free survival rates in the analysis group were 74.1% and 45.3%, respectively. An ¹⁸F-fluorodeoxyglucose-positron emission tomography response after 2 courses of DCF therapy was significantly associated with OS (P = .0049).

Conclusions: In patients with resectable ESCC, dCRT for remarkable responders downstaging to stage IA after induction chemotherapy with 3 courses of DCF therapy is a feasible treatment option and provides an optimizing organ-preservation strategy of chemotherapy-based selection.