Survival of elderly patients with glioblastoma after hypofractionated radiation therapy

Abstract

Background. Glioblastoma (GB) is the most common primary brain tumor that is malignant, and its incidence increases with age. The prognosis for elderly patients with GB (GBe) is significantly worse than that of younger patients. Due to the global trend of aging population and age-related features of the GB cohort, the number of GBe patients is expected to increase. Although there is no full consensus regarding the clinical management of GBe, hypofractionated radiation therapy (RT) has become a common therapeutic option for elderly and/or poor prognosis GB patients.
 Purpose. To analyze the survival of patients with glioblastoma in the age group ≥60 years old after standard and hypofractionated regimens of adjuvant radiation therapy.
 Materials and methods. A retrospective single-center non-randomized study based on a total cohort of 53 patients (≥60 years old) with histogically verified diagnosis of GB was performed at the State Institution «Romodanov Neurosurgery Institute of the National Academy of Medical Sciences of Ukraine» over the period of 6 years, from 2014 to 2020. According to the RT regimen, patients were stratified into 2 groups: standard RT (SRT group) – 16 (30.2%) patients (30 fractions, 2.0 Gy per fraction, total radiation dose – 60.0 Gy) and hypofractionated RT (HRT group) – 37 (69.8%) patients (15 fractions, 3.5 Gy per fraction, total dose – 52.5 Gy). Cancer-specific survival (CSS) and progression-free survival (PFS) were analyzed in the total cohort and both groups separately.
 Results. With a median follow-up of 21.9 months (95% CI (confidence interval) 20.7 – 32.3), the median CSS in the total cohort was 15.0 (95% CI 13.3 – 17.3) months; the median PFS – 9.0 (95% CI 8.0 – 10.6) months. In the HRT group, the median CSS was 14.7 (95% CI 10.5 – 18.5) months; in the SRT group – 15.0 (95% CI 12.4 – 19.3) months. In the HRT group, the median PFS was 9.0 (95% CI 7.0 – 11.9) months; in the SRT group – 9.0 (95% CI 8.0 – 11.0) months. Before and after the stratification point of 15 months, the HRT and SRT groups did not differ significantly in CSS (Log-rank test p = 0.0588 and p = 0.2009, respectively). There was no significant difference in PFS between the HRT and SRT groups before and after the stratification point of 9 months (Log-rank test p = 0.0653 and p = 0.0722, respectively). Conclusions. Improving survival of GBe pts is an urgent issue, especially taking into account global trends in population aging and age-specific features of GB. The proposed hypofractionated RT regime can be considered as an optional approach in the complex treatment of GBe pts.