Radiation Therapy and Tamoxifen in Treating Adults With Newly Diagnosed Supratentorial Glioblastoma Multiforme

DISEASE CHARACTERISTICS: Histologically proven newly diagnosed, supratentorial glioblastoma multiforme (with areas of necrosis) Diagnosis must be made by surgical biopsy or excision within the past 5 weeks No recurrent malignant gliomas No metastases below the tentorium or beyond the cranial vault PATIENT CHARACTERISTICS: Age: Adult Performance status: Karnofsky 70-100% OR Zubrod 0-1 Life expectancy: At least 8 weeks Hematopoietic: Hemoglobin at least 10 g/dL (transfusion allowed) Hematocrit at least 30% (transfusion allowed) Absolute neutrophil count at least 1,500/mm3 Platelet count at least 100,000/mm3 Hepatic: Bilirubin no greater than 2.0 mg/dL serum glutamate pyruvate transaminase (SGPT) or serum glutamate oxaloacetate transaminase (SGOT) no greater than 2 times normal Renal: Blood urea nitrogen no greater than 25 mg/dL Creatinine no greater than 1.5 mg/dL Cardiovascular: No active thrombophlebitis Other: Recovered from any postoperative infection or other complications No major medical illnesses or psychiatric impairments that would preclude study participation No active connective tissue disorder, such as lupus or scleroderma No other malignancy within the past 5 years except nonmelanomatous skin cancer or carcinoma in situ of the cervix or bladder No prior endometrial cancer or atypical endometrial hyperplasia No AIDS Not pregnant or nursing Fertile patients must use effective contraception PRIOR CONCURRENT THERAPY: Biologic therapy: Not specified Chemotherapy: Not specified Endocrine therapy: At least 12 months since prior tamoxifen Radiotherapy: See Disease Characteristics No prior radiotherapy to head or neck Surgery: See Disease Characteristics Recovered from prior surgery