A Phase II Study of High-Dose-Rate Esophageal Brachytherapy After External Beam Radiotherapy and Nivolumab in Patients With Locally Advanced Esophageal Squamous Cell Carcinoma
The goal of this clinical trial is to learn if adding high-dose-rate (HDR) brachytherapy can improve outcomes in patients with locally advanced esophageal squamous cell carcinoma (ESCC) who have already received external beam radiotherapy (EBRT), chemotherapy, and the immune therapy drug nivolumab. The main questions it aims to answer are: * Does HDR brachytherapy reduce the chance of the cancer coming back in the esophagus or nearby areas within 12 months? * What side effects or safety issues occur when HDR brachytherapy is given after EBRT, chemotherapy, and nivolumab? Participants will: * Receive 1-2 sessions of HDR brachytherapy delivered through a thin tube placed inside the esophagus, within three weeks after starting nivolumab. * Continue nivolumab and be monitored with regular follow-up visits, imaging tests, and blood samples to check treatment response and safety.
• Age of 18-85 years, with ECOG performance 0-2.
• Locally-advanced esophageal squamous cell carcinoma with clinical stage III, IVA with biopsy proven.
• Prior treatment with EBRT (40-50.4 Gy in 20-28 fractions) and platinum + fluoropyrimidine chemotherapy, with residual or progressive disease, and deemed inoperable or unable to undergo surgery.
• No prior exposure to ICIs and had received first cycle of nivolumab after CCRT.
• Biopsy proven with PD-L1 \[tumor cell (TC) ≥ 1%\]
• Required at least one measurable or non-measurable lesion per Response Evaluation Criteria in Solid Tumors (RECIST), version 1.1.
• Patients with limited stage IVB disease (e.g., non-visceral lymph node metastasis) may be enrolled if the primary tumor is locally dominant and suitable for brachytherapy, based on investigator's discretion.