2557 - National Trends on Use of Radiotherapy for Elderly Patients with Glioblastoma: A National Cancer Data Base Study
Presenter(s)
R. J. Afzal1, D. M. Edwards2, J. Takayesu3, S. Hardy4, L. M. Halasz5, S. S. Lo5, L. Ni6, and Y. D. Tseng5; 1University of Pikeville Kentucky College of Osteopathic Medicine, Pikeville, KY, 2Department of Radiation Oncology, University School of Medicine, Indianapolis, IN, 3Department of Radiation Oncology, University of Michigan, Ann Arbor, MI, 4Department of Radiation Oncology, University of Rochester Medical Center, Rochester, NY, 5Department of Radiation Oncology, University of Washington/ Fred Hutchinson Cancer Center, Seattle, WA, 6Department of Radiation Oncology, University of California San Francisco, San Francisco, CA
Purpose/Objective(s): Randomized trials have shown hypofractionated radiation to be non-inferior to conventional radiation for elderly patients with glioblastoma (GBM). Using the National Cancer Data Base (NCDB), we analyzed management patterns by age, and associations between radiation dose and survival.
Materials/Methods: We queried the NCDB database (2005–2021) for patients with GBM 50 years or older. Continuous variables were compared via T-test, and survival was assessed with Cox proportional hazards models and propensity score matching, adjusting for age, race, Charlson-Deyo index, treatment year, insurance, surgery, chemotherapy and MGMT status.
Results: Our study identified 46,366 patients, with 14,751 patients (31.8%) 70 years or older. The median age of those receiving standard fractionation (>50 Gy) was significantly lower compared to those who received a hypofractionated course (<50 Gy) (63.0 vs. 72.0 years, p<0.001). The proportion of patients receiving hypofractionated radiation increased with age: 8.7% (50–55), 10.3% (55–60), 12.8% (60–65), 19.8% (65–70), 33.3% (70–75), 44.9% (75–80), and 59.9% (80+). 41.3% of patients 70 years or older received hypofractionated radiation. Age, Charleson-Deyo score, year of diagnosis, insurance, and chemotherapy use were significantly associated with the use of standard fractionation (p < 0.001). Radiation dose (HR 1.24, 95% CI 1.12 -1.38, p=<0.01), black race (HR 1.18, 95% CI 1.05 – 1.32, p=0.01), year of diagnosis (HR 2.03, 95% CI 1.98 – 2.08, p<0.01), and biopsy only (HR 1.59, 95% CI 1.41 – 1.79, p<0.01) were associated with worse survival based on our Cox model. Survival analyses were also run on a subset of patients 70 years and older who had MGMT methylation status available (N=3,667). When correcting for the covariates listed above, radiation dose was not associated with survival in our propensity score matched model (HR 0.96, 95% CI 0.81 – 1.13, p=0.63).
Conclusion: Despite guidelines recommending hypofractionated radiation for elderly patients with, we demonstrate that in practice less than half of patients over the age of 70 receive hypofractionated courses. These findings underscore the need for improved tools for risk stratification to determine which elderly patients might benefit from standard fractionation. While the absence of performance status in this dataset represents a significant limitation, providers should use caution in offering standard fractionation for elderly patients, given the limited data to support a survival benefit with longer courses.