DISEASE CHARACTERISTICS:

• Histologically confirmed intracranial glioblastoma multiforme (GBM) or gliosarcoma by biopsy or resection within the past 28 days

PATIENT CHARACTERISTICS:

Age

• 18 and over

Performance status

• Karnofsky 60-100%

Life expectancy

• More than 8 weeks

Hematopoietic

• WBC at least 3,000/mm^3
• Absolute neutrophil count at least 1,500/mm^3
• Platelet count at least 100,000/mm^3
• Hemoglobin at least 10 g/dL (transfusion allowed)

Hepatic

• Bilirubin less than 2 times upper limit of normal (ULN)
• SGOT less than 2 times ULN

Renal

• Creatinine less than 1.5 mg/dL

Other

• No significant medical illness that cannot be controlled adequately with appropriate therapy or that would compromise tolerability of study therapy
• No other cancer (except nonmelanoma skin cancer or carcinoma in situ of the cervix) unless in complete remission and off all therapy for that disease for at least 3 years
• No active infection
• No disease that would obscure toxicity or dangerously alter drug metabolism
• No other serious concurrent medical illness
• Not pregnant or nursing
• Negative pregnancy test
• Fertile patients must use effective contraception

PRIOR CONCURRENT THERAPY:

Biologic therapy

• Not specified

Chemotherapy

• No prior polifeprosan 20 with carmustine implant (Gliadel wafer)
• No concurrent chemotherapy

Endocrine therapy

• Concurrent corticosteroids to treat symptoms or prevent complications are allowed

Radiotherapy

• No prior radiotherapy to the brain
• No concurrent stereotactic radiosurgery
• No concurrent brachytherapy

Surgery

• See Disease Characteristics

Other

• No prior cytotoxic or noncytotoxic drug therapy for GBM
• No prior experimental drug therapy for GBM
• No other concurrent cytotoxic or noncytotoxic drug therapy for GBM
• Concurrent analgesics, antiepileptics, or other drugs to treat symptoms or prevent complications are allowed