Inclusion Criteria

DISEASE CHARACTERISTICS:

- Diagnosis of 1 of the following:

- Epithelial neoplasms metastatic to the central nervous system

- Recurrent or refractory to prior chemotherapeutic or radiotherapeutic
regimens or for which no standard chemotherapy or whole brain radiotherapy
regimens exist

- Stage IV disease

- Recurrent glial tumors (brain or spinal cord)

- Received prior whole brain radiotherapy or stereotactic radiotherapy OR refused
radiotherapy

- Patients with CNS metastases previously treated with radiotherapy are eligible,
provided persistent or progressive CNS metastases are documented by MRI eight
weeks after the end of radiotherapy

- Patients with glial tumors must show progressive disease by MRI after prior
radiotherapy

- Measurable disease in the brain/leptomeninges of the brain or spinal cord with
baseline documentation within 4 weeks of study entry

- Must have ≥ 1 lesion that is ≥ 1 cm on MRI scan

- Ineligible for or has refused participation in higher priority institutional
protocols

PATIENT CHARACTERISTICS:

- Karnofsky performance status 50-100%

- Life expectancy ≥ 2 months

- Creatinine ≤ 1.5 mg/dL

- WBC 4,000/mm³ OR ANC ≥ 2,000/mm³

- Platelet count ≥ 150,000/mm³

- Bilirubin ≤ 1.5 mg/dL

- ALT and AST < 2 times upper limit of normal

- Not pregnant

- Negative pregnancy test

- Fertile patients must use effective contraception

- No nonmalignant concurrent illness (e.g., cardiovascular or pulmonary) that is either
poorly controlled with currently available treatment or of such severity to preclude
study entry

- No severe infection

- Patients who are ineligible for lumbar puncture are allowed

PRIOR CONCURRENT THERAPY:

- See Disease Characteristics

- At least 3 weeks since prior radiotherapy, immunotherapy, or chemotherapy OR
recovered from expected side effects of prior therapy

- No patients who are recovering from major surgery

- No concurrent radiotherapy

- Concurrent steroid or anticonvulsant therapy allowed