RATIONALE: Radiation therapy uses high-energy x-rays to damage tumor cells. Chemotherapy uses different ways to stop tumor cells from dividing so they stop growing or die. Combining radiation therapy with chemotherapy may kill more tumor cells.

PURPOSE: Randomized phase III trial to study the effectiveness of radiation therapy and carmustine in treating patients who have supratentorial glioblastoma multiforme.

OBJECTIVES: I. Determine whether the use of radiosurgery (stereotactic external-beam irradiation) prior to conventional radiotherapy with carmustine (BCNU) improves overall survival compared to conventional radiotherapy plus BCNU alone in patients with supratentorial glioblastoma multiforme. II. Determine and compare the frequency and severity of toxicities associated with these regimens. III. Compare the effects of these two regimens on neurologic function and quality of life.

OUTLINE: Randomized study. Arm I: Radiotherapy plus Single-Agent Chemotherapy. Tumor irradiation using megavoltage equipment (at least 4 MV photons); plus Carmustine, BCNU, NSC-409962. Arm II: Radiosurgery followed by Radiotherapy plus Single-Agent Chemotherapy. Stereotactic tumor irradiation; followed by tumor irradiation as in Arm I; plus BCNU.

PROJECTED ACCRUAL: 200 patients will be entered over approximately 3 years.

DISEASE CHARACTERISTICS: Histopathologically confirmed supratentorial glioblastoma multiforme or gliosarcoma Diagnosis by surgical biopsy or resection required The following tumor types are specifically excluded: Astrocytoma with atypical or anaplastic features Well differentiated astrocytomas Tumors originating in the brain stem Tumors located within 10 mm of the optic chiasm Infratentorial tumors Multifocal malignant glioma Recurrent malignant glioma Well circumscribed contrast-enhancing tumor on pre- and postoperative contrast-enhanced CT or MRI with a maximum diameter (in any direction) of 40 mm required Tumors that do not enhance on postoperative CT or MRI excluded Concurrent enrollment on RTOG-9308 encouraged

PATIENT CHARACTERISTICS: Age: 18 and over Performance status: Karnofsky 60-100% Life expectancy: At least 3 months Hematopoietic: ANC at least 1,500 Platelets at least 100,000 Hb at least 10 g/dl (may transfuse) Hepatic: Bilirubin no greater than 2.0 mg/dl SGOT or SGPT no greater than 2 x normal Renal: Creatinine no greater than 1.5 mg/dl BUN no greater than 25 mg/dl Pulmonary: Chest x-ray normal If abnormal or if there is a history of pulmonary disease, pulmonary function studies (including DLCO) must be at least 75% of predicted Other: Neurologic function status 0-3 No AIDS No major medical or psychiatric illness that would preclude protocol therapy or follow-up No second malignancy within 5 years except: Nonmelanomatous skin cancer In situ carcinoma of the uterine cervix

PRIOR CONCURRENT THERAPY: Biologic therapy: Not specified Chemotherapy: No prior chemotherapy Endocrine therapy: Not specified Radiotherapy: No prior radiotherapy to the head and neck Surgery: No more than 5 weeks between surgery and initiation of treatment Recovery from surgery and any postoperative complications required