Stereotactic Radiation & Abemaciclib in the Management of HR+/HER2- Breast Cancer Brain Metastases

This study is testing abemaciclib (a targeted oral therapy that blocks cancer cell division) combined with stereotactic radiosurgery (a very precise, focused form of radiation) for women with hormone receptor-positive, HER2-negative breast cancer that has spread to the brain. **You may be eligible if:** - You have HR+/HER2- breast cancer with up to 15 brain tumors eligible for stereotactic radiosurgery - Your tumors are small enough (largest is 4 cm or less) for focused radiation - You can swallow oral medications - Your overall health is good (ECOG 0–2) - You have measurable brain disease on imaging **You may NOT be eligible if:** - Your brain tumors are too large or too numerous for stereotactic radiosurgery - You are unable to take oral medications - You have significant other health conditions that would make the study unsafe - You are pregnant or breastfeeding Talk to your doctor to see if this trial is right for you.