PRIOR CONCURRENT THERAPY: Biologic therapy: Not specified Chemotherapy: At least 6 weeks since prior adjuvant chemotherapy No other prior or concurrent chemotherapy allowed Endocrine therapy: Concurrent corticosteroids allowed Stable or decreasing dose for at least 2 weeks Radiotherapy: No high dose radiotherapy, stereotactic radiosurgery, or internal radiotherapy unless recurrence is histologically confirmed At least 3 months since prior radiotherapy to the brain Surgery: No prior surgery for recurrent brain tumor except biopsy At least 3 months since prior surgery for primary brain tumor Other: No other concurrent anticancer therapy No other concurrent investigational therapy