An Observational Clinical Study of Stereotactic Radiotherapy for Advanced Non-Small Cell Lung Cancer With Stable Disease After PD-1 Inhibitor Treatment

This study is investigating whether stereotactic body radiation therapy (SBRT) — a highly precise form of radiation that delivers large doses over a few sessions — can help control advanced non-small cell lung cancer (NSCLC) in patients whose disease has stabilized ('stable disease') after initial immunotherapy. **You may be eligible if...** - You are 18 or older - You have Stage IIIB, IIIC, or IV non-small cell lung cancer confirmed by biopsy - You received 3–4 cycles of a PD-1 immunotherapy drug (with or without chemotherapy) and your cancer showed stable disease (not growing, not responding dramatically) - Your cancer does not have EGFR, ALK, or ROS1 mutations - You have measurable disease and good general health (ECOG 0–1) - You have good heart and lung function **You may NOT be eligible if...** - Your tumor has known driver gene mutations (EGFR, ALK, or ROS1 positive) - You have serious liver or kidney problems - You had serious side effects during your prior immunotherapy - You have been on steroids or immune-suppressing drugs recently Talk to your doctor to see if this trial is right for you.