Reducing the Incidence of Symptomatic Brain Metastases With MRI Surveillance

This study tests whether regular brain MRI scans (surveillance imaging) after treatment for locally advanced lung cancer can catch brain metastases (tumors that spread to the brain) earlier — before they cause symptoms — and whether earlier detection leads to better outcomes. **You may be eligible if...** - You are 18 or older - You have locally advanced non-squamous lung cancer (stage IIIA, IIIB, or IIIC) that is being treated with radiation therapy - You do not have known brain metastases on your staging scans - You are able to have an MRI safely - You have adequate kidney function (GFR above 30 mL/min) - You are enrolled before or shortly after starting radiation, with your first surveillance MRI at approximately 120 days after radiation begins **You may NOT be eligible if...** - You already have known brain metastases - You cannot have an MRI (e.g., due to a pacemaker or certain metal implants) - Your cancer is purely squamous cell type Talk to your doctor to see if this trial is right for you.