Inclusion Criteria

DISEASE CHARACTERISTICS:

- Diagnosis of brain metastasis from a histologically confirmed solid tumor, meeting
the following criteria:

- Must have histologic proof of original malignancy

- No germ cell tumor metastasis

- Biopsy-proven brain metastasis preferred when clinical history and radiographic
findings are equivocal

- At least 1 unidimensionally measurable lesion ≥ 50 mm by head contrast CT scan and/or
brain MRI

- Patients enrolled in the phase II portion of the study must meet the following
Radiation Therapy Oncology Group Recursive Partitioning Analysis staging criteria for
brain metastases:

- Class II classification

- Zubrod performance status 0-1 AND any of the following:

- Age > 65 years

- Extracranial metastasis

- Uncontrolled primary malignancy

PATIENT CHARACTERISTICS:

- Zubrod performance status 0-1

- Life expectancy ≥ 3 months

- Able to participate in the Mini-Mental Status Examination

- WBC ≥ 3,000/mm³

- Absolute neutrophil count ≥ 1,500/mm³

- Platelet count ≥ 100,000/mm³

- Bilirubin ≤ 1.5 mg/dL

- AST ≤ 2.5 times upper limit of normal (ULN) (5 times ULN if liver metastases are
present)

- Hemoglobin ≥ 9.0 g/dL

- Not pregnant or nursing

- Negative pregnancy test

- Fertile patients must use effective contraception

- No concurrent medical disease that, in the investigator's opinion, would preclude
study participation

PRIOR CONCURRENT THERAPY:

- More than 21 days since prior chemotherapy

- No prior whole-brain radiotherapy

- No prior DNA topoisomerase I drugs (e.g., irinotecan hydrochloride, topotecan
hydrochloride)

- At least 4 days since prior and no concurrent known CYP3A4 inducers, including any of
the following:

- Phenytoin

- Carbamazepine

- Phenobarbital

- Hypericum perforatum (St. John's wort)