Inclusion Criteria

DISEASE CHARACTERISTICS:

- Histologically proven unifocal anaplastic astrocytoma or mixed gliomas, including the
following:

- Anaplastic oligoastrocytoma

- Mixed oligodendroglial/astrocytic tumors

- Oligodendroglial component must be no greater than 25%

- No vascular proliferation and necrosis

- Increased cellularity, pleomorphism, and nuclear atypia allowed

- No tumor predominantly located in the posterior fossa (i.e., brainstem or cerebellum)

- Patients with prior biopsy proven low grade astrocytoma who now have anaplastic
astrocytoma and have had no prior radiotherapy or chemotherapy also eligible

- Study therapy must begin within 6 weeks of diagnosis

- No spinal cord tumors, spinal drop metastases, or metastases to noncontiguous
meninges

- Pathologic evidence of local meningeal infiltration by underlying tumor allowed

PATIENT CHARACTERISTICS:

Age:

- 18 and over

Performance status:

- Karnofsky 60-100%

Life expectancy:

- At least 1 year

Hematopoietic:

- Hemoglobin at least 10 g/dL

- Absolute neutrophil count at least 1,500/mm^3

- Platelet count at least 150,000/mm^3

Hepatic:

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

- AST less than 2 times ULN

- Alkaline phosphatase less than 2 times ULN

Renal:

- Blood urea nitrogen no greater than 25 mg/dL

- Creatinine less than 1.5 times normal

Pulmonary:

- No pre-existing lung disease that, in the investigator's opinion, would preclude
administration of carmustine or lomustine or completion of therapy

Other:

- No other major medical illness or psychiatric impairment that would preclude study
compliance

- No other malignancy within the past 5 years except nonmelanomatous skin cancer or
carcinoma in situ of the cervix

- No known hypersensitivity to 1 of the components of carmustine, lomustine,
temozolomide, dacarbazine, or any other nitrosourea

- No active infection

- Not pregnant or nursing

- Negative pregnancy test

- Fertile patients must use effective contraception

PRIOR CONCURRENT THERAPY:

Biologic therapy:

- No prior biologic therapy

Chemotherapy:

- See Disease Characteristics

- No prior chemotherapy

Endocrine therapy:

- Not specified

Radiotherapy:

- See Disease Characteristics

- No prior radiotherapy to brain or head and neck

Surgery:

- Not specified

Other:

- No other concurrent anticancer treatment for anaplastic astrocytoma until a
recurrence is detected