P09.08 Hypofractionated versus standard radiotherapy with or without temozolomide for elderly patients with glioblastoma

Abstract

INTRODUCTION: The optimal management of patients aged ≥ 65 years with newly diagnosed glioblastoma (GB) is evolving. In the UK, hypofractionated radiotherapy (HRT: 30 Gy in 6 fractions over 2 weeks) has been the standard of care for individuals aged >70 years with PS=0-1, any age with PS≥2, and/or multifocal tumours. Occasionally, patients aged >70 years with PS 0-1 and no medical comorbidities may be considered for standard radiotherapy (SRT-60 Gy in 30 fractions over 6 weeks) with or without temozolomide (TMZ). MATERIALS AND METHODS: In this retrospective study we analysed the outcome of radiotherapy for patients aged ≥ 65 years with glioblastoma treated between 2009 and 2015. Survival was calculated the Kaplan-Meier method. Differences in patient-and disease-related factors between the HRT and SRT groups were compared using the Fisher exact test. The Cox-proportional hazard regression analysis was used to correlate these factors with survival. RESULTS: Patients received HRT (n=45), SRT (n= 8) or SRT with TMZ (n=15). The median age was 71.5 years (range: 65 to 83 years). 30 patients were aged 65-70 years and 38 were >70 years. 35 patients underwent debulking surgery and the remaining had either a biopsy (n=29) or a radiological diagnosis (n=4). 21 patients had multifocal disease. Patients receiving HRT were significantly older (median age 75 years vs. 69 years, p=0.003), had worse PS (≥2) (p=0.000), and the majority had only a biopsy or radiological diagnosis (p=0.021), compared with those receiving SRT with or without temozolomide Patients who received SRT+/-TMZ had a better median overall (11 vs. 5 months; p=0.000) and progression-free survival (9 vs. 3 months, p=0.040) compared with patients who received HRT. The corresponding 1-year OS for both groups were 43.5% and 6.7% respectively. On univariate analysis, overall survival correlated with PS (HR=0.42, 95% CI:0.24-0.74), multifocality (HR=2.07, 95% CI 1.21-3.55), and age (HR=0.96, 95% CI: 0.99-1.09), but not with the extent of resection (HR=1.44, 95% CI 0.95-2.18). MGMT methylation status was not available for all patients and therefore, not analysed. CONCLUSION: SRT with or without TMZ may improve survival in selected patients aged ≥ 65 years with newly diagnosed glioblastoma. The survival of patients treated with SRT+/-TMZ in our cohort is better than that of patients treated with chemo-radiotherapy in the recently published EORTC 26062-22061 study. An individualised-approach should be favoured over a one-fits-all strategy in the management of elderly patients with glioblastoma.