Identifying Predictive Factors for Radiation Necrosis vs. Local Recurrence in Biopsy-Proven Enlarging Lesions Post-Stereotactic Radiosurgery for Brain Metastases

Lay Summary Cancers that spread to the brain are often treated with focused radiation. After treatment, brain scans sometimes show that the treated area continues to grow, which can mean radiation-related brain injury or the cancer growing back. We reviewed 151 growing areas post-treatment that had tissue samples taken during surgery and confirmed as radiation injury or cancer growing back. Older age, tissue samples taken nine months or more after treatment, and higher radiation doses to the healthy brain were associated with radiation-related injury. These findings may help doctors choose between urgent treatment and close observation, improving care and avoiding unnecessary treatment.