DISEASE CHARACTERISTICS:

• Histologically confirmed renal cell carcinoma, melanoma, or sarcoma with 1-3 newly diagnosed intraparenchymal brain metastases based on contrast-enhanced MRI (CT scan acceptable if patients have a medical contraindication to MRI)
• No lesion greater than 4.0 cm in diameter and, if multiple lesions are present, no more than one greater than 3.0 cm in diameter
• No limitation on the extent of extracranial metastatic disease
• No metastases in the brain stem, midbrain, pons, or medulla
• No leptomeningeal metastases documented by MRI or CSF evaluation
• No metastases within 10 mm of optic nerve or chiasm
• No history of multiple liver metastases

PATIENT CHARACTERISTICS:

Age:

• 18 and over

Performance status:

• ECOG 0-2

Life expectancy:

• At least 3 months

Hematopoietic:

• Absolute neutrophil count greater than 1,000/mm^3
• Platelet count greater than 50,000/mm^3
• Hemoglobin greater than 8 g/dL

Hepatic:

• Not specified

Renal:

• Not specified

Other:

• No major medical illness
• No psychoses
• Not pregnant or nursing
• Fertile patients must use effective contraception

PRIOR CONCURRENT THERAPY:

Biologic therapy:

• Not specified

Chemotherapy:

• Prior chemotherapy allowed
• Systemic chemotherapy may be continued at the discretion of investigator after completion of radiosurgery

Endocrine therapy:

• Not specified

Radiotherapy:

• No prior cranial radiotherapy
• Prior or concurrent radiotherapy to noncranial sites allowed

Surgery:

• No prior surgical resection for brain metastases
• Prior stereotactic biopsy for diagnostic purposes allowed