DISEASE CHARACTERISTICS:

• Histologically confirmed glioblastoma multiforme (GBM) or gliosarcoma

  • Newly diagnosed by surgical biopsy or excision within the past 5 weeks

• Supratentorial location, as determined by the following:

  • Contrast-enhanced MRI performed preoperatively
  • MRI performed postoperatively within 28 days prior to study entry (preferably within 72 hours of surgery)
  • Postoperative scan not required if diagnosed by stereotactic biopsy and pre-operative MRI was performed
• No gliomas graded < GBM
• No recurrent malignant gliomas
• No tumor foci detected below the tentorium or beyond the cranial vault
• No multifocal disease or leptomeningeal spread

PATIENT CHARACTERISTICS:

• Zubrod performance status 0-1
• Neurologic function status 0-2
• Absolute neutrophil count ≥ 1,800 cells/mm^3
• Platelet count ≥ 100,000 cells/mm^3
• Hemoglobin ≥ 8 g/dL (transfusion allowed)
• BUN ≤ 25 mg/dL
• Creatinine ≤ 1.5 mg/dL
• Bilirubin ≤ 1.5 mg/dL
• ALT or AST ≤ 2 times upper limit of normal
• Fertile patients must use effective contraception during and for 2 months after completion of study treatment
• Negative pregnancy test
• Not pregnant or nursing
• No prior invasive malignancies, except for nonmelanomatous skin cancer and carcinoma in situ of the uterine cervix or bladder, unless disease-free for ≥ 3 years

• No severe, active comorbidity, defined as follows:

  • Unstable angina and/or congestive heart failure requiring hospitalization within the past 6 months
  • Transmural myocardial infarction within the past 6 months
  • Acute bacterial or fungal infection requiring intravenous antibiotics at study entry
  • Chronic obstructive pulmonary disease exacerbation or other respiratory illness requiring hospitalization or precluding study therapy within 30 days prior to study entry
  • Coagulation defects
  • Known AIDS
• No prior allergic reaction to the study drugs
• No history of porphyria or G6PD deficiency
• No allergy to gadolinium or contraindications to MRI

PRIOR CONCURRENT THERAPY:

• See Disease Characteristics
• Recovered from effects of surgery or postoperative infection and other complications

• No prior systemic chemotherapy, including polifeprosan 20 with carmustine implant (Gliadel wafer), for the current GBM

  • Prior chemotherapy for a different cancer allowed
• No prior radiotherapy to the head and neck (except for T1 glottic cancer) that would result in overlap of radiation therapy fields
• No prophylactic filgrastim (G-CSF) during the first course of study treatment
• No concurrent sargramostim (GM-CSF)
• No other concurrent chemotherapy