Cancer Clinical Research Unit

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