OBJECTIVES:: Age is an unfavorable prognostic factor in glioblastoma multiforme (GBM). To assess the possibility and the advantage of radiotherapy (RT) plus concomitant/sequential temozolomide (TMZ) in patients over 65 years with GBM, we analyzed 4 prospective trials in terms of compliance and outcomes. METHODS:: Elderly patients with histologically proven GBM, included in 4 prospective phase II studies with a Karnofsky Performance Status (KPS) >70 and a Charlson Comorbidity Index (CCI) <3, were selected for these analyses. Patients were treated by 3D-conformal RT (60 Gy), fractionated stereotactic conformal-RT (69.4 Gy), or intensity-modulated RT with simultaneous integrated boost (63 Gy). Concomitant (standard modality, first and last week, or from the Monday to Friday) and adjuvant chemotherapy with TMZ was administered. To stratify patients, recursive partitioning analysis was used. Safety and tolerability were measured by the National Cancer Institute Common Criteria. Progression-free survival (PFS) and overall survival (OS) were calculated by Kaplan-Meier method. RESULTS:: From 2001 to 2011, 201 patients were enrolled in 4 trials and 111 elderly patients were recruited for this analysis. Compliance was 96.4%: 4/111 patients discontinued treatment, prevalently for disease progression. During radiochemotherapy, acute toxicity was mild. At a median follow-up of 64 months (range, 9 to 122 mo), median PFS and OS were 10 and 13 months, respectively. Extent of surgery (P=0.009) and radiation dose (P=0.01) significantly improved survival. CONCLUSIONS:: Radiochemotherapy is effective and well tolerated by elderly patients when KPS >70 and CCI <3; therefore these criterions should be considered to enroll elderly patients in combined prospective study.