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.