DISEASE CHARACTERISTICS:

• Newly diagnosed grade III or IV glioma including any of the following:

  • Glioblastoma
  • Anaplastic astrocytoma
  • Gliosarcoma
  • Anaplastic oligodendroglioma
  • Anaplastic oligoastrocytoma
• Measurable or nonmeasurable disease

• No more than 5 weeks since prior brain surgery

  • Recovered from surgery, post- operative infection, and other complications

• Preoperatively and postoperatively diagnostic contrast-enhanced MRI or CT scan of the brain performed prior to radiation therapy

  • Patients diagnosed by stereotactic biopsy do not require the postoperative scan

PATIENT CHARACTERISTICS:

• Karnofsky performance status ≥ 60%
• Absolute neutrophil count ≥ 1,500/mm^3
• Platelet count ≥ 100,000/mm^3
• Serum creatinine ≤ 1.5 times upper limit of normal (ULN)
• Total bilirubin ≤ 2.0 mg/dL
• AST ≤ 4.0 times ULN
• No prolonged QT interval > 460 milliseconds on baseline electrocardiogram in the presence of normal serum potassium and magnesium
• No uncontrolled electrolyte imbalance (i.e., sodium < 132 mmol/L, potassium < 3.5 mEq/dL, magnesium < 1.7 mg/dL)
• No history of torsades de pointes type of ventricular arrhythmia
• Negative pregnancy test
• Not pregnant or nursing
• Fertile patients must use effective contraception
• No medical or psychiatric illness that, in the investigator's opinion, could potentially preclude the completion of study therapy
• No HIV positivity
• No active connective tissue disorders (e.g., lupus or scleroderma) that, in the investigator's opinion, may put the patient at high risk for radiation toxicity

PRIOR CONCURRENT THERAPY:

• See Disease Characteristics
• No prior brain radiotherapy or chemotherapy for brain tumor
• Concurrent corticosteroids to control cerebral edema allowed provided dose is stable or decreasing for the past 5 days
• No concurrent or plan to receive drugs that are known to prolong the QT interval
• No prior radiation to the head or neck (except for T1 glottic cancer) resulting in overlap of radiation fields