Abstract
Age remains the most powerful prognostic factor among glioblastoma (GBM) patients. Half of all patients with GBM are aged 65 years or older at the time of diagnosis, and the incidence rate of GBM in patients aged over 65 years is increasing rapidly. Median survival for elderly GBM patients is less than 6 months and reflects less favorable tumor biologic factors, receipt of less aggressive care, and comorbid disease. The standard of care for elderly GBM patients remains controversial. Based on limited data, extensive resection appears to be more beneficial than biopsy. For patients with favorable Karnofsky performance status (KPS), adjuvant radiotherapy (RT) has a demonstrated survival benefit with no observed decrement in quality of life. Concurrent and adjuvant temozolomide (TMZ) along with RT to 60 Gy have not been prospectively studied among patients aged over 70 years but should be considered for patients aged 65-70 years with excellent KPS. Based on the recent NOA-08 and Nordic randomized trials, testing for O(6)-methylguanine-DNA-methyltransferase (MGMT) promoter methylation should be performed routinely immediately after surgery to aid in adjuvant treatment decisions. Patients aged over 70 years with favorable KPS, or patients aged 60-70 years with borderline KPS, should be considered for monotherapy utilizing standard TMZ dosing for patients with MGMT-methylated tumors, and hypofractionated RT (34 Gy in ten fractions or 40 Gy in 15 fractions) for patients with MGMT-unmethylated tumors. The ongoing European Organisation for Research and Treatment of Cancer/National Cancer Institute of Canada trial will help clarify the role for concurrent TMZ with hypofractionated RT. For elderly patients with poor KPS, reasonable options include best supportive care, TMZ alone, hypofractionated RT alone, or whole brain RT for symptomatic patients needing to start treatment urgently. Given the balance between short survival and quality of life in this patient population, optimal management of elderly GBM patients must be made individually according to patient age, MGMT methylation status, performance score, and patient preferences.