Safety and Tolerability of Low Dose Radiotherapy Concurrent SBRT and PD-1 Inhibitors in Advanced NSCLC.

This study is testing whether combining two types of radiation — low-dose whole-body radiation plus targeted high-dose radiation (SBRT) — together with an immunotherapy drug (a PD-1 inhibitor) is safe for people with advanced lung cancer that has stopped responding to standard therapy. **You may be eligible if...** - You are 18 or older with stage IV non-small cell lung cancer confirmed by biopsy or lab test - Your cancer has progressed after or is not suitable for standard treatment - You have at least one tumor larger than 5 cm that can be targeted with radiation - Your general health score is 0–2 and your life expectancy is more than 3 months - Your blood counts, liver, and kidney function meet required levels **You may NOT be eligible if...** - Your cancer is still responding to standard treatment - You do not have any measurable tumors on imaging - Your organ function is too poor to tolerate the treatment - You are pregnant or have serious uncontrolled medical conditions Talk to your doctor to see if this trial is right for you.