Radiation Therapy With or Without Temozolomide in Treating Patients With Low-Grade Glioma

DISEASE CHARACTERISTICS:

• Histologically confirmed* supratentorial low-grade glioma, including 1 of the following:

• Grade 2 astrocytoma

• Grade 2 oligodendroglioma

• Grade 2 oligoastrocytoma (mixed glioma containing astrocytoma and oligodendroglioma)

• NOTE: *If the pathology from multiple procedures supports the diagnosis of a brain tumor, the qualifying pathology of grade 2 astrocytoma, oligodendroglioma, or oligoastrocytoma must be the most recent pathological diagnosis; no pathological diagnosis of grade 3 or 4 glioma at any time

• Paraffin-embedded tumor specimen available for submission for confirmation of pathological review and determination of 1p and 19q deletion status

• Patients must currently meet ≥ 1 of the following criteria*:

• Uncontrolled symptoms, defined as any of the following:

• Headaches associated with mass effect

• Uncontrolled seizures despite two different antiepileptic drug regimens (i.e., two antiepileptic drugs tested either sequentially or in combination)

• Focal neurological symptoms

• Cognitive symptoms or deficits

• Tumor progression by serial MRIs, defined as any of the following:

• New or progressive enhancement

• New or progressive T2 or FLAIR signal abnormality

• Age ≥ 40 years

• NOTE: *Patients < 40 years of age whose only symptom of low-grade glioma is seizures that are well-controlled on antiepileptic drugs AND who have no evidence of radiographic progression are not eligible.

• Patients who have undergone gross total resection and have no detectable residual disease are eligible

• No pilocytic astrocytoma, ganglioglioma, pleomorphic xanthoastrocytoma, or dysembryoplastic neuroepithelial tumors

PATIENT CHARACTERISTICS:

• Karnofsky performance status 60-100%

• WBC ≥ 3,000/mm^3

• ANC ≥ 1,500/mm^3

• Platelet count ≥ 100,000/mm^3

• Hematocrit ≥ 30%

• Bilirubin ≤ 2 times upper limit of normal (ULN)

• AST and ALT ≤ 3 times ULN

• Creatinine ≤ 2.0 times ULN

• Not pregnant or nursing

• Negative pregnancy test

• Able to undergo MRI with and without contrast

• No other malignancy within the past 5 years, except for nonmelanoma skin cancer or cervical carcinoma in situ

• No uncontrolled infection

• No known HIV positivity

• No medical disorder that would increase risks associated with radiotherapy and temozolomide

• No other disorder that would limit life expectancy to < 5 years

PRIOR CONCURRENT THERAPY:

• No prior radiotherapy, cytotoxic chemotherapy, radiosurgery, or investigational therapy directed at the brain tumor

• Any number of prior surgical procedures for the brain tumor allowed

• No prior radiotherapy to the head unless the radiotherapy ports entirely excluded the brain

• At least 2 weeks since any prior brain surgery (e.g., stereotatic biopsy, open biopsy, or resection)

• At least 6 weeks since prior MRI and chest x-ray

• If resection is performed, an MRI after surgery is required