This phase II clinical trial involves the use of hippocampal-sparing together with stereotactic radiosurgery (SRS) for the treatment of brain metastases. The standard of care in the treatment of brain metastases is cranial radiation, but this can be associated with significant neurocognitive sequelae, including reduced verbal memory, spatial memory, attention and problem solving. This can be minimized with the use of SRS, rather than whole brain radiotherapy (WBRT).

Additionally, some of the neurotoxicity has been linked to damage in neural progenitor cells contained within the hippocampus. A recent phase III clinical trial has demonstrated reduced neurocognitive decline with use of hippocampal-sparing techniques in WBRT. This trial aims to see if this can be further improved by combining SRS and hippocampal-sparing.

Primary objective: To determine the rate of neurocognitive failure with hippocampal-sparing stereotactic radiosurgery compared to neurocognitive failures rates with hippocampal-sparing whole brain radiotherapy (using NRG-CC001 with the same population as our comparison), assessed at baseline and at months 3, 6 and 12 (+/- 2 weeks), and with failure defined as any decline in at least one of the following tests (of note, we will be using alternate forms to avoid practice effects): Hopkins Verbal Learning Test for total recall, delayed recall and delayed recognition, Controlled oral word association, Trail making tests parts A and B, Brief visuospatial memory test-revised.

Secondary objectives:

(I) To determine if hippocampal-sparing preserves neurocognitive function, assessed at baseline and months 3, 6 and 12 (+/- 2 weeks), and defined as decline in at least one of the following tests (of note, we will be using alternate forms to avoid practice effects): Hopkins Verbal Learning Test for total recall, delayed recall and delayed recognition, Controlled oral word association, Trail making tests parts A and B, Brief visuospatial memory test-revised.

(II) To determine the incidence of adverse events up to 12 months post-treatment, as measured by common terminology criteria for adverse events (CTCAE v3.0) (III) Quality of life As measured using MD Anderson Symptom Inventory for Brain tumor (MDASI-BT)'s four subscales: symptom severity, symptom interference, neurologic failure and cognitive factor score; and individual items (fatigue, neurologic factor items and cognitive factor items).

(III) Oncologic outcomes will also be assessed at surveillance every 3 months, as is standard of care; time to intracranial progression, overall survival. These will be estimated using Kaplan-Meier method.

Inclusion Criteria:

• 18 years of age or older
• Either gender
• Patients must provide informed consent prior to registration
• Pathologically (histologically or cytologically) proven diagnosis of solid tumor malignancy
• Brain metastase(s) outside a 5-mm margin around either hippocampus
• Brain metastase(s) must be visible on contrast-enhanced magnetic resonance imaging (MRI); an allowed exception for patients who had undergone radiosurgery or surgical resection and are planning adjuvant radiotherapy do not have to have visible disease.
• Patients must have a gadolinium contrast-enhanced three-dimensional MRI scan, whether diagnostic or a MR simulation scan
• Karnofsky performance status of >= 70 or ECOG >= 2
• Patients may have had prior therapy for brain metastasis, including radiosurgery, as long as with hippocampal-sparing, and surgical resection; patients must have completed prior therapy (no specific time lapse between prior treatment and this treatment)

Exclusion Criteria:

• Prior external beam radiation therapy to the brain or whole brain radiation therapy, unless radiosurgery with hippocampal-sparing
• Radiographic evidence of hydrocephalus or other architectural distortion of the ventricular system, including placement of external ventricular drain or ventriculoperitoneal shunt
• Patients with definitive leptomeningeal metastases
• Contraindication to magnetic resonance (MR) imaging such as implanted metal devices or foreign bodies
• Contraindication to gadolinium contrast administration during MR imaging, such as allergy or insufficient renal function

We do not plan to make individual patient data available to other researchers