Hippocampal Sparing Whole Brain Radiation Versus Stereotactic Radiation in Patients With 5-20 Brain Metastases: A Phase III, Randomized Trial

Inclusion Criteria: * Participants must have a biopsy proven solid malignancy with untreated (by radiation) intracranial lesions radiographically consistent with or pathologically proven to be brain metastases. Patients who have undergone prior systemic therapy are eligible * Five-twenty intracranial lesions must be present on MRI of the brain * Age 18-80 years at diagnosis of brain metastases * Karnofsky performance status of at least 70 Exclusion Criteria: * Participants who have undergone prior radiation for brain metastases. * Patients who have undergone resection of one or more brain metastases but who have not yet started adjuvant radiotherapy are eligible for the study * Participants who cannot undergo a brain MRI * Participants who cannot receive gadolinium (MRI contrast) * Participants with stage IV-V chronic kidney disease or end stage renal disease * Participants with widespread, definitive leptomeningeal disease * Participants with small cell lung cancer, lymphoma, or myeloma * Participants with a maximum tumor diameter exceeding 5 cm (if not resected)