Adjuvant Radiotherapy for Esophageal Squamous Cell Carcinoma in the Era of Immunotherapy

This study is a multicenter, prospective, randomized phase II trial aimed at exploring the value of adjuvant radiotherapy in patients at high risk of recurrence after neoadjuvant chemoradiotherapy for esophageal cancer. The study primarily includes patients with esophageal cancer who underwent neoadjuvant chemoradiotherapy and surgery and did not achieve complete pathological response (non-pCR) postoperatively and were defined as preoperative clinical stage at T3-4N+M0. Eligible patients will be randomized in a 1:1 ratio into two groups: the observation group and the adjuvant radiotherapy group. The control group consists of patients who receive surgery after neoadjuvant chemotherapy combined with immunotherapy for esophageal cancer, followed by maintenance therapy with PD1/PDL1 inhibitors for up to 1 year or until tumor progression. The adjuvant radiotherapy group receives additional adjuvant radiotherapy on top of the control group's treatment. The specific treatment process involves receiving 2 cycles of neoadjuvant chemotherapy combined with immunotherapy (PD1/PDL1 inhibitors) before potentially curative esophageal cancer surgery. The chemotherapy regimen includes paclitaxel in combination with platinum agents, with a preference for albumin-bound paclitaxel (280mg/m2 on Day 1, or 100mg on Days 1, 8, and 15) in combination with carboplatin (AUC=5). Following surgery, patients start adjuvant radiotherapy 4-6 weeks after the operation, with a radiation dose of 45Gy/25F/5W, completed no later than 8 weeks post-surgery. Two weeks after completing radiotherapy, patients continue with immunotherapy maintenance therapy for up to 1 year or until tumor progression. Subsequently, follow-up visits are scheduled every 3-4 months for the first 3 years, every 6 months for the next 2 years, and annually thereafter. The primary endpoint is 2-year disease-free survival (DFS), and secondary endpoints include overall survival (OS), local recurrence-free survival (LRFS), distant metastasis-free survival (DMFS), recurrence patterns, and safety assessment. Additionally, the study will explore biomarkers predicting treatment efficacy and adverse reactions in subjects, including PD-L1 expression, ctDNA clearance status, infiltrating immune cell types and quantities, cytokine expression, and other tumor biomarkers. This exploration aims to guide stratified precision treatment for patients.