DISEASE CHARACTERISTICS:

• Metastatic lesions to the brain

  • Must not require immediate radiotherapy
  • If received prior radiotherapy, must have progressive disease
• Evaluable disease by CT scan or MRI
• Neurologically stable

PATIENT CHARACTERISTICS:

Age:

• 18 and over

Performance status:

• Karnofsky 70-100%

Life expectancy:

• More than 12 weeks

Hematopoietic:

• Absolute neutrophil count at least 1,500/mm^3
• Platelet count at least 100,000/mm^3
• Hemoglobin at least 10 g/dL

Hepatic:

• Bilirubin less than 1.5 times upper limit of normal (ULN)
• SGOT or SGPT less than 2.5 times ULN
• Alkaline phosphatase less than 2 times ULN

Renal:

• Blood urea nitrogen less than 1.5 times ULN
• Creatinine less than 1.5 times ULN

Other:

• Not pregnant or nursing
• Negative pregnancy test
• Fertile patients must use effective contraception
• No other concurrent nonmalignant systemic disease
• No acute infection requiring treatment with IV antibiotics
• HIV negative
• No frequent vomiting or medical condition that would preclude oral medication administration (e.g., partial bowel obstruction, inability to swallow)

PRIOR CONCURRENT THERAPY:

Biologic therapy:

• No concurrent hematopoietic growth factors, including epoetin alfa
• No other concurrent biologic therapy

Chemotherapy:

• At least 4 weeks since prior chemotherapy, unless evidence of disease progression
• No other concurrent chemotherapy

Endocrine therapy:

• Concurrent corticosteroids allowed if nonincreasing dose for at least 1 week prior to study

Radiotherapy:

• See Disease Characteristics
• At least 4 weeks since prior radiotherapy to the brain, unless evidence of disease progression
• No concurrent radiotherapy

Surgery:

• At least 3 weeks since prior surgery, unless evidence of disease progression, and recovered

Other:

• No other concurrent investigational drugs