Phase II multicenter trial: first-line immunochemotherapy with or without radiotherapy in metastatic esophageal squamous cell cancer (SCR-ESCC-01).

This randomized phase II trial (NCT05978193) combines low-dose radiotherapy (LDRT) and conventionally fractionated radiotherapy (CFRT) with immunochemotherapy for metastatic esophageal squamous cell carcinoma, aiming to assess the potential enhanced effect of radiotherapy on immunotherapy. Patients are administered a PD-1 inhibitor along with paclitaxel and platinum-based chemotherapy (arm B), or combined with LDRT and CFRT (arm A). Immunotherapy is given every 3 weeks with chemotherapy for 4 cycles, followed by immunotherapy maintenance therapy for up to 24 months. In arm A, LDRT (2 Gy, 2 fractions; delivered to the primary and all metastatic tumors) precedes each immunochemotherapy cycle for 4 cycles, followed by CFRT (40-50 Gy, 20-25 fractions; delivered to the primary tumor) starting from the fifth immunotherapy cycle. The primary end point is median progression-free survival. Clinical Trial Registration: NCT05978193 (clinicaltrials.gov).