DISEASE CHARACTERISTICS:

• Histologically confirmed high-grade malignant glioma of one of the following subtypes:

  • Glioblastoma
  • Anaplastic astrocytoma
  • Anaplastic oligoastrocytoma
  • Gliomatosis cerebri
• No disseminated disease or primary spinal cord malignancies
• Measurable intracranial residual disease by MRI

PATIENT CHARACTERISTICS:

Age:

• 3 and over
• Under 22 at time of diagnosis

Performance status:

• Karnofsky 50-100% if over 10 years of age
• Lansky 50-100% if 10 years of age or under

Life expectancy:

• At least 8 weeks

Hematopoietic:

• Absolute neutrophil count at least 1,000/mm^3
• Platelet count at least 100,000/mm^3 (transfusion independent)
• Hemoglobin at least 8.0 g/dL (RBC transfusions allowed)

Hepatic:

• Bilirubin no greater than 1.5 times normal for age
• SGPT no greater than 2.5 times normal for age
• Albumin at least 2 g/dL

Renal:

• Creatinine no greater than 1.5 times normal for age OR
• Creatinine clearance or radioisotope glomerular filtration rate at least lower limit of normal for age

Pulmonary:

• No dyspnea at rest
• No exercise intolerance
• Pulse oximetry at least 94%

Other:

• Not pregnant or nursing
• Negative pregnancy test
• Fertile patients must use effective contraception
• No uncontrolled infection

PRIOR CONCURRENT THERAPY:

Biologic therapy:

• No prior biologic therapy
• No concurrent prophylactic hematopoietic growth factors

Chemotherapy:

• No prior chemotherapy

Endocrine therapy:

• Prior corticosteroid therapy allowed
• No concurrent corticosteroids as antiemetic

Radiotherapy:

• No prior radiotherapy

Surgery:

• No more than 31 days since prior maximal neurosurgical procedure

Other:

• No concurrent phenobarbital or cimetidine