RATIONALE: Radiation therapy uses high-energy x-rays to damage tumor cells. Drugs used in chemotherapy use different ways to stop tumor cells from dividing so they stop growing or die. It is not yet known if radiation therapy is more effective with or without temozolomide for glioblastoma multiforme.

PURPOSE: Randomized phase III trial to compare the effectiveness of radiation therapy with or without temozolomide in treating patients who have newly diagnosed glioblastoma multiforme.

OBJECTIVES: I. Compare the efficacy of radiotherapy with or without temozolomide in terms of overall survival in patients with newly diagnosed glioblastoma multiforme. II. Compare the toxicity profiles of these regimens in these patients. III. Compare the progression free survival of these patients treated with these regimens. IV. Compare the quality of life in these patients treated with these regimens.

OUTLINE: This is a randomized, multicenter study. Patients are stratified according to participating center, age (under 50 vs 50 and over), WHO/ECOG performance status (0-1 vs 2), and extent of surgical resection (biopsy only vs complete or incomplete resection). Patients are randomized to one of two treatment arms. Arm I: Patients undergo radiotherapy 5 days a week for 6 weeks. Arm II: Patients undergo radiotherapy as in arm I concurrently with oral temozolomide daily for 6 weeks. Patients then receive adjuvant oral temozolomide alone on days 1-5 every 28 days for 6 courses beginning 4 weeks after completion of radiotherapy. Quality of life is assessed prior to the study, at week 4 during radiotherapy, at 4 weeks after completion of radiotherapy, at the end of courses 3 and 6 of adjuvant chemotherapy (arm II), and then every 3 months until disease progression. Patients are followed every 3 months until disease progression or death.

PROJECTED ACCRUAL: A total of 520 patients (260 per treatment arm) will be accrued for this study within 3.5 years.

DISEASE CHARACTERISTICS: Histologically confirmed newly diagnosed glioblastoma multiforme by biopsy or surgical resection Grade IV disease Initial diagnosis no greater than 6 weeks prior to study

PATIENT CHARACTERISTICS: Age: 18 to 70 Performance status: WHO 0-2 Life expectancy: Not specified Hematopoietic: Absolute neutrophil count at least 1,500/mm3 Platelet count at least 100,000/mm3 Hepatic: Bilirubin no greater than 1.5 times upper limit of normal (ULN) AST or ALT less than 2.5 times ULN Alkaline phosphatase less than 2.5 times ULN No chronic hepatitis B or C Renal: Creatinine no greater than 1.5 times ULN Other: Not pregnant or nursing Negative pregnancy test Fertile patients must use effective contraception No known HIV infection No medical condition that would interfere with oral medication intake (e.g., frequent vomiting or partial bowel obstruction) No other prior or concurrent malignancy except surgically cured carcinoma in situ of the cervix or nonmelanoma skin cancer No serious medical, psychological, familial, sociological, or geographical condition that would preclude study

PRIOR CONCURRENT THERAPY: Biologic therapy: No concurrent filgrastim (G-CSF), sargramostim (GM-CSF), or epoetin alfa No concurrent biologic therapy No concurrent immunotherapy Chemotherapy: No prior chemotherapy No other concurrent chemotherapy Endocrine therapy: At least 14 days of prior corticosteroids at a stable dose required Concurrent corticosteroids allowed Radiotherapy: No prior radiotherapy No concurrent stereotactic boost radiotherapy Surgery: See Disease Characteristics No concurrent surgery for tumor debulking Other: No other concurrent investigational drugs