This study will assess the effect of a one-week radiotherapy regimen in comparison with a three-week radiotherapy regimen on the survival of elderly and/or frail patients with glioblastoma multiforme (Frail: ≥>50 years old and with a KPS of 50% or less50%-70%; Elderly and frail: ≥65 years and with a KPS of 50% - 70%; Elderly: ≥65 years and with a KPS of 80% - 100%).