Utilization of hypofractionated radiation therapy in older glioblastoma patients

Background: Though the optimal treatment regimen in older patients with glioblastoma multiforme (GBM) remains to be established, multiple randomized studies have supported the use of hypofractionated (1–3 weeks) versus traditional regimens (6 weeks). Here we examine hypofractionated regimen practice patterns among older patients with GBM. Methods: We used the National Cancer Database and included individuals aged ≥65 years with GBM diagnosed from 2005 to 2014 undergoing biopsy/resection followed by chemotherapy and radiation initiated ≤8-weeks of diagnosis. We defined traditional fractionation as ≤200 cGy and hypofractionation as >200 cGy. We compared patient characteristics using a chi-squared test and multivariable logistic regression. We compared 90-day mortality rates following initiation of radiation using the Wald statistic in propensity score matched cohorts. Results: The final cohort included 14,931 individuals with 1524 undergoing hypofractionated treatment. From 2005 to 2014 hypofractionated utilization rates were 7%, 9%, 13%, and 18% among those 65–69, 70–74, 75–79, and ≥80 years of age, respectively. Patients treated at an academic/research center had a >60% increased odds (OR, 1.61; 95% CI, 1.43–1.81) of undergoing hypofractionated regimens versus a community center. Ninety-day mortality rates were high in both groups (hypofractionated: 32%; traditional: 24%; p <.001). Conclusions: The majority of older GBM patients do not undergo hypofractionated radiation. High 90-day mortality in both groups suggests that hypofractionation may improve the survival-to-treatment time ratio and positively impact patient quality of life. Hypofractionated radiation regimens for GBM should be discussed with older patients and considered for inclusion in efforts to improve the quality and value of cancer care.