Temozolomide in Treating Patients With Progressive Low-Grade Glioma

DISEASE CHARACTERISTICS:

* Histologically confirmed progressive, primary, intracranial, supratentorial, low-grade glioma including:

  * Astrocytoma
  * Oligodendroglioma
  * Mixed glioma
  * Optic pathway glioma\*
  * Pontine glioma\* NOTE: \*Biopsy not required
* Patients with optic pathway glioma must also meet the following criteria:

  * Progressive loss of vision as defined by doubling of octaves
  * Visual acuity loss not explained by other causes
  * Increase in proptosis of greater than 3 mm
  * Increase in diameter of optic nerve of at least 2 mm on neuroimaging
  * Increase in distribution of tumor involving optic tracts or optic radiations as indicated by CT scan or MRI

PATIENT CHARACTERISTICS:

Age:

* 4 and over

Performance status:

* Karnofsky 70-100%

Life expectancy:

* More than 12 weeks

Hematopoietic:

* Absolute neutrophil count at least 1,500/mm\^3
* Platelet count at least 100,000/mm\^3
* Hemoglobin at least 10 g/dL

Hepatic:

* Bilirubin less than 1.5 times upper limit of normal (ULN)
* SGOT and SGPT less than 2.5 times ULN
* Alkaline phosphatase less than 2 times ULN

Renal:

* Creatinine less than 1.5 times ULN
* BUN less than 1.5 times ULN

Other:

* Must be neurologically stable
* No systemic disease
* No acute infection requiring IV antibiotics
* No frequent vomiting
* No other medical condition that would interfere with oral medication (e.g., partial bowel obstruction)
* No other prior or concurrent malignancies except:

  * Surgically cured carcinoma in situ of the cervix
  * Basal or squamous cell skin cancer
* HIV negative
* No AIDS-related illness
* Not pregnant or nursing
* Fertile patients must use effective contraception

PRIOR CONCURRENT THERAPY:

Biologic therapy:

* No concurrent biologic therapy (growth factors or epoetin alfa)

Chemotherapy:

* At least 6 weeks since prior chemotherapy unless evidence of disease progression
* No other concurrent chemotherapy

Endocrine therapy:

* Not specified

Radiotherapy:

* At least 6 weeks since prior radiotherapy unless evidence of disease progression
* No concurrent radiotherapy

Surgery:

* At least 3 weeks since prior surgery unless evidence of disease progression
* Recovered from all prior surgery

Other:

* No other concurrent investigational drugs