Inclusion Criteria

DISEASE CHARACTERISTICS: Histologically confirmed supratentorial * grade I/II glioma,
including: Diffuse fibrillary astrocytoma No pilocytic astrocytoma No mixed tumor with
ependymoma elements * Supratentorial sites include: Frontal, temporal, parietal, or
occipital lobes Thalamus, basal ganglia, or midbrain Lateral or third ventricles Pons,
medulla, or optic chiasm tumors allowed only if secondary to eligible tumor More than 1
separate tumor allowed Diagnosis based on surgical biopsy or subtotal resection Measurable
or evaluable disease on T2-weighted MRI required

PATIENT CHARACTERISTICS: Age: 18 and over Performance status: ECOG 0-2 Hematopoietic: WBC
greater than 3,500/mm3 Platelet count greater than 130,000/mm3 Hemoglobin greater than 9
g/dL 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: Creatinine less than 1.5 times
ULN Other: No active or uncontrolled infection No second malignancy within 3 years except:
Nonmelanomatous skin cancer In situ cervical cancer No pregnant or nursing women Negative
pregnancy test required within 7 days prior to entry Effective contraception required of
fertile patients

PRIOR CONCURRENT THERAPY: Biologic therapy: Not specified Chemotherapy: No prior
chemotherapy Endocrine therapy: At least 1 week since prior steroids OR Stable steroid
dose for at least 1 week prior to study Radiotherapy: No prior cranial or head and neck
irradiation Surgery: See Disease Characteristics