PULSAR Combined With Immunotherapy and Chemotherapy

This study tests a treatment approach that combines focused radiation (called PULSAR — Personalized Ultra-fractionated Stereotactic Adaptive Radiotherapy) with immunotherapy and chemotherapy (gemcitabine and cisplatin) for people with advanced bile duct cancer (cholangiocarcinoma) that cannot be surgically removed. **You may be eligible if...** - You are between 18 and 75 years old - You have locally advanced or metastatic cholangiocarcinoma confirmed by biopsy or cell testing - You have at least one measurable tumor - You are in good physical condition (ECOG 0–1) - Your expected survival is at least 3 months - Your organs function well enough for all three treatment types **You may NOT be eligible if...** - You have contraindications to immunotherapy drugs, gemcitabine, cisplatin, or radiation - You have conditions that make any part of the combined treatment unsafe Talk to your doctor to see if this trial is right for you.