Inclusion Criteria

DISEASE CHARACTERISTICS:

- Histologically confirmed progressive and/or symptomatic low-grade glioma, including
any of the following:

- WHO grade I or II astrocytoma

- Grade I or II oligodendrogliomas

- Mixed oligodendrogliomas

- Gangliogliomas

- Measurable disease

- Progressive and/or symptomatic supratentorial or spinal cord tumors that cannot be
removed for anatomical reasons are allowed

- Optic pathway tumors allowed provided there is evidence of progressive disease by MRI
and/or symptoms of deteriorating vision, progressive hypothalamic/pituitary
dysfunction, or diencephalic syndrome

- Dorsally exophytic brainstem gliomas that were previously resected more than 50% are
allowed provided the residual tumor shows progression (with or without symptoms)

- No diffuse brain stem tumors

- No type 1 neurofibromatosis

PATIENT CHARACTERISTICS:

Age

- 10 and under

Performance status

- ECOG 0-2

- Lansky 50-100%

Life expectancy

- Not specified

Hematopoietic

- Hemoglobin ≥ 8.0 gm/dL

- Absolute neutrophil count ≥ 1,000/mm^3

- Platelet count ≥ 100,000/mm^3

Hepatic

- Bilirubin ≤ 1.5 times upper limit of normal (ULN)

- ALT < 2.5 times ULN

Renal

- Creatinine clearance or radioisotope glomerular filtration rate ≥ 70 mL/min OR

- Creatinine ≤ 0.8 mg/dL (age 5 and under) OR ≤ 1.0 mg/dL (age 6 to10)

Other

- Not pregnant or nursing

- Negative pregnancy test

- Fertile patients must use effective contraception during and for 2 months after study
participation

PRIOR CONCURRENT THERAPY:

Biologic therapy

- No concurrent immunomodulating agents

Chemotherapy

- No other concurrent anticancer chemotherapy

Endocrine therapy

- Prior corticosteroids allowed

- No concurrent corticosteroids except for the treatment of increased intracranial
pressure

Radiotherapy

- Not specified

Surgery

- See Disease Characteristics

- Prior surgery allowed

Other

- No other prior therapy