Low-Dose Radiotherapy in Patients With Advanced Esophageal Squamous Cell Carcinoma Resistant to First-Line Chemotherapy Combined With Immunotherapy

Brief Summary The goal of this single-arm Phase II clinical trial is to learn whether low-dose radiotherapy (LDRT) can restore sensitivity to immunotherapy and prolong disease control in adults with advanced esophageal squamous cell carcinoma who have progressed after first-line chemotherapy combined with PD-1/PD-L1 inhibitors. The main questions it aims to answer are: * Can LDRT followed by continued immunotherapy increase progression-free survival compared with historical data? * What is the objective response rate after adding LDRT to ongoing immunotherapy? * Is LDRT combined with immunotherapy safe in this heavily pre-treated population? Participants will: * Receive a single fraction of 2 Gy to every visible metastatic lesion within one week * Continue their prior PD-1/PD-L1 inhibitor (e.g., camrelizumab, pembrolizumab) after LDRT is completed * Undergo tumor imaging every 6 weeks for up to one year to monitor response * Provide optional blood and tissue samples for exploratory biomarker studies

NCT Number	NCT07164690
Lead Sponsor	Fudan University
Conditions	Esophageal Adenocarcinoma, Radiotherapy
Enrollment	32 participants
Start Date	2025-09
Primary Completion	2026-07 (estimated)
Study Completion	2027-07 (estimated)
Updated on ClinicalTrials.gov	2025-09-10