Irinotecan and Whole-Brain Radiation Therapy in Treating Patients With Brain Metastases From Solid Tumors

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)