Glioblastoma Treatment in the Elderly

Although current treatment advances prolong patient survival, treatment for glioblastoma (GBM) in the elderly has become an emerging issue. The definition of "elderly" differs across articles; GBM predominantly occurs at an age >= 65 years, and the prognosis worsens with increasing age. Regarding molecular markers, isocitrate dehydrogenase (IDH) mutations are less common in the elderly with GBM. Meanwhile, O-6-methylguanine DNA methyltransferase (MGMT) promoter methylation has been identified in approximately half of patients with GBM. Surgery should be considered as the first-line treatment even for elderly patients, and maximum safe resection is recommended if feasible. Concurrently, radiotherapy is the standard adjuvant therapy. Hypofractionated radiotherapy (e.g., 40 Gy/15 Fr) is suitable for elderly patients. Studies also supported the concurrent use of temozolomide (TMZ) with radiotherapy. In cases wherein elderly patients cannot tolerate chemoradiation, TMZ monotherapy is an effective option when MGMT promoter methylation is verified. Conversely, tumors with MGMT unmethylated promoter may be treated with radiotherapy alone to reduce the possible toxicity of TMZ. Meanwhile, the efficacy of bevacizumab (BEV) in elderly patients remains unclear. Similarly, further studies on the efficacy of carmustine wafers are needed. Based on current knowledge, we propose a treatment diagram for GBM in the elderly.