A Study of Neoadjuvant Stereotactic Radiosurgery for Large Brain Metastases

Inclusion Criteria: * Lymphoma, small cell carcinoma, and seminoma are excluded * A lesion appropriate for resection, not previously treated with SRS. Lesions should be \> 2 cm and \< 4 cm in largest dimension, and require resection ( e.g. due to mass effect or to obtain a tissue diagnosis). Index lesions will be treated with SRS and surgery, as outlined in the treatment section of the protocol. * Seen by a neurosurgeon or radiation oncologist and judged to be appropriate for participation in this study, including the ability to tolerate NaSRS, e.g., the ability to lie flat in a stereotactic head frame. * Any unresected lesions or lesions for which there is no planned immediate resection (non index lesions) must measure \< 3.0 cm in maximal extent on the contrasted MRI or CT brain scan obtained ≤ 35 days prior to pre-registration. Unresected lesions will be treated with SRS as outlined in the treatment section of the protocol. . * ECOG ≤ 2 * MRI confirmed 1-6 lesions, one of which is the index lesion. Each non-index lesion (up to 5) must measure ≤ 3.0 cm in maximal extent on contrasted MRI scan, and not otherwise require resection. Note: The pre-registration MRI may be obtained ≤ 35 days prior to enrolment. Exclusion Criteria: * Treatment plan respecting normal tissue tolerances using dose fractionation specified within the protocol cannot be achieved. * pregnancy * Prior cranial radiotherapy targeting the index lesion, or any prior WBRT. * Inability to complete a MRI with contrast of the head, or a known allergy to gadolinium. * Cytotoxic Chemotherapy within 7 days prior to SRS (molecularly targeted therapies , including immune-modulatory drugs, can be given within seven days of SRS at the discretion of the treating physician) * Metastatic germ cell tumor, small cell carcinoma, or lymphoma or any primary brain tumor * Imaging Findings: * Widespread definitive leptomeningeal metastasis. * A brain metastasis that is located ≤ 2 mm of the optic chiasm * Evidence of midline shift * Fourth ventricular narrowing, concerning for hydrocephalus