Stereotactic Body Radiotherapy for Oligo-Progression Metastatic Non-Small Cell Lung Cancer

This study is testing whether adding stereotactic body radiotherapy (SBRT) — a precise, high-dose form of radiation — to ongoing chemotherapy plus immunotherapy can help patients with advanced non-small cell lung cancer (NSCLC) whose cancer is progressing in only a small number of spots (called "oligo-progression"). The idea is that treating those specific progression sites may extend the benefit of the existing treatment. **You may be eligible if...** - You are 18 or older - You have confirmed stage IV non-small cell lung cancer - You previously benefited from first-line chemotherapy for at least 3 months - Your cancer is now progressing in 5 or fewer sites, all outside the brain, that are suitable for SBRT - You have adequate overall health, organ function, and blood counts **You may NOT be eligible if...** - You are pregnant or breastfeeding - You have untreated brain metastases causing symptoms - You have had another cancer in the past 3 years (other than certain skin cancers) - Your progression sites cannot be safely treated with SBRT - You are currently in another interventional trial that could interfere with this study Talk to your doctor to see if this trial is right for you.