High-grade gliomas are the most commonly diagnosed malignant brain tumor in adults. Prognosis can be estimated by examining risk factors, including histology, age and performance status. Postoperative radiation therapy is associated with improved survival and standard treatment includes external beam radiotherapy to a dose of 60 Gy in 30–33 fractions. Patients with poor prognostic features have a more limited benefit from radiotherapy. This article reviews the current state of knowledge on risk stratification and analyzes strategies that can be employed to better individualize treatment for poor-prognosis patients.