WBRT With Hippocampal-avoidance Technique Followed by SRT for Extensive-stage SCLC With Baseline Brain Metastases

This study is looking at a specific approach to brain radiation therapy for people with small cell lung cancer that has already spread to the brain when first diagnosed. It tests whole-brain radiation that carefully avoids the hippocampus (a memory-related brain region) followed by targeted radiation boosts to brain tumors, aiming to slow cancer while protecting thinking and memory. **You may be eligible if...** - You have been newly diagnosed with extensive-stage small cell lung cancer AND have brain metastases at diagnosis - Your cancer has been confirmed by tissue biopsy or cell analysis - You are planned to receive at least 4 cycles of standard platinum-based chemotherapy combined with immunotherapy - You have brain tumors that qualify for targeted stereotactic radiation (fewer than or equal to 10 tumors, each under 3 cm) - Your overall health and organ function are adequate **You may NOT be eligible if...** - You have had prior brain radiation - You have leptomeningeal disease (cancer spreading along the lining of the brain/spine) - You are pregnant or breastfeeding - Your general health status is too poor (ECOG score 3 or higher) Talk to your doctor to see if this trial is right for you.