Inclusion Criteria

DISEASE CHARACTERISTICS:

- Histologically proven unifocal or multifocal, supratentorial, pure or mixed
anaplastic oligodendroglioma

- Prior suspected or proven low-grade glioma allowed if current histologic proof
of pure or mixed anaplastic oligodendroglioma

- Tumor must contain an unequivocal (at least 25%) oligodendroglial element and have 2
or more anaplastic features, 1 of which must be frequent mitoses or endothelial
proliferation

- For mixed tumors, the non-oligodendroglial element must be astrocytic and the
oligodendroglial or astroglial component may be anaplastic

- No evidence of spinal drop metastasis or spread to noncontiguous meninges

- MRI of spine not required for asymptomatic patients and patients not excluded
based on pathologic evidence of local meningeal infiltration by underlying tumor

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

- No spinal cord tumors

PATIENT CHARACTERISTICS:

Age:

- 18 and over

Performance status:

- Karnofsky 60-100%

Life expectancy:

- Not specified

Hematopoietic:

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

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

Hepatic:

- Bilirubin no greater than 2 times normal

- SGOT no greater than 2 times normal

- Alkaline phosphatase no greater than 2 times normal

Renal:

- Creatinine no greater than 1.5 times normal

Pulmonary:

- No chronic lung disease unless DLCO is at least 60% predicted

Other:

- No active infection

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

- Not pregnant or nursing

- Negative pregnancy test

- Fertile patients must use effective contraception

PRIOR CONCURRENT THERAPY:

Biologic therapy:

- Not specified

Chemotherapy:

- No prior chemotherapy

Endocrine therapy:

- No concurrent steroids as antiemetics

- Concurrent steroids allowed to control CNS symptoms due to tumor-associated or
radiotherapy-associated cerebral edema

Radiotherapy:

- No prior radiotherapy to brain or head/neck

Surgery:

- Prior surgery allowed