DISEASE CHARACTERISTICS:

• Part I:

  • Histologically confirmed, newly diagnosed glioblastoma multiforme or anaplastic astrocytoma (closed to accrual 12/19/2000)

• Parts I and II:

  • Histologically confirmed astrocytic, oligodendroglial, or mixed glial tumor

    • Grade III or higher
    • Recurrent or progressive after radiotherapy
• Evaluable residual disease by contrast-enhanced MRI or CT scan

PATIENT CHARACTERISTICS:

Age:

• 18 and over

Performance status:

• Karnofsky 60-100%

Life expectancy:

• Not specified

Hematopoietic:

• Granulocyte count at least 1,500/mm3
• Platelet count at least 100,000/mm3

Hepatic:

• SGOT no greater than 2.5 times upper limit of normal
• Bilirubin normal

Renal:

• Creatinine no greater than 1.5 mg/dL OR
• Creatinine clearance greater than 60 mL/min
• BUN no greater than 25 mg/dL

Other:

• Not pregnant or nursing
• Negative pregnancy test
• Fertile patients must use effective contraception during and for 2 months after study

PRIOR CONCURRENT THERAPY:

Biologic therapy:

• At least 6 weeks since prior biologic therapy and recovered

Chemotherapy:

• At least 2 weeks since prior chemotherapy (including but not limited to topotecan) and recovered

  • Patients in trials with one of the following treatment combinations are allowed to enroll 6 weeks after receiving carmustine (BCNU):

    • BCNU on day 1
    • BCNU on day 1 and topotecan on days 1, 8, 15, 22, 29, and 36
    • BCNU on day 1 and irinotecan on days 1, 8, 15, and 22

Endocrine therapy:

• Patients on corticosteroids must be on a stable dose for at least 2 weeks before study
• At least 6 weeks since other prior endocrine therapy and recovered

Radiotherapy:

• See Disease Characteristics
• At least 6 weeks since prior radiotherapy and recovered

Surgery:

• Not specified