[en] To determine the safety and effectiveness of accelerated hyperfractionated radiotherapy in the treatment of supratentorial malignant astrocytomas. Between June 1995-July 1997, 75 patients were enrolled to a prospective phase 11 study. A total dose of 60 Gy was delivered in 2 Gy b.i.d. fractions with an interval of 6-8 h, 5 days per week, in an overall time of 3 weeks. The treatment protocol was planned to give 40 Gy to a treatment volume covering the contrast-enhancing lesion and oedema (+ 3-cm margin) and additional 20 Gy to the volume encompassing the contrast-enhancing lesion alone with a 1-cm margin based on preoperative magnetic resonance imaging and/or CT findings. The patients had a median age of 46 years and a median Karnofsky performance status score of 80. Histology consisted of anaplastic astrocytoma (AA) in 16 (21%) and glioblastoma multiforme (GBM) in 59 (79%) patients. Median survival was 11 months for all patients; 10 months for GBM patients and 40 months for AA patients. Survival rates at 1 and 3 years were 41 %, 11% for all patients; 62, 37% for AA patients and 35, 6% for GBM patients, respectively. Multivariate analysis revealed significant impact of age, histology and neurological functional class on survival. The incidence of grade 3 or worse late neurological toxicity was 5.3%. Although accelerated hyperfractionated radiotherapy showed no significant advantage on survival, it shortened the treatment period from 6 to 3 weeks. Radiotherapy was well tolerated and the incidence of late toxicity is acceptable. (author)