2558 - Early Initiation of Radiation Therapy Improves Survival in Elderly Patients with Glioblastoma
Presenter(s)
N. Almeida1, T. Schrand2, V. Madhugiri1, M. Fang1, R. Shekher1, V. Goulenko1, K. Snyder1, L. Lipinski1, A. Fabiano1, R. Fenstermaker1, and D. Prasad1; 1Roswell Park Comprehensive Cancer Center, Buffalo, NY, 2Tulane University School of Medicine, New Orleans, LA
Purpose/Objective(s): To study the impact of early initiation of radiation therapy (RT) in elderly patients with newly diagnosed glioblastoma
Materials/Methods: Patient demographic and outcomes were obtained from our prospective patient registry between 2020-2024. The study population consisted of 56 elderly patients, defined as those aged 65 years and older, with a new diagnosis of IDH-wildtype glioblastoma who underwent surgical resection followed by RT. Survival analysis was conducted to evaluate the impact of timing of RT initiation on survival outcomes. Specific cut-off points for significant improvement were identified using the log-rank test. Kaplan-Meier curves were used to illustrate survival distributions. The association of each interested risk factor with the survival outcomes were first examined using univariate Cox regression model. Multivariate analysis was applied to evaluate the effect of multiple explanatory variables simultaneously on the survival outcomes. Results were presented as hazard ratio (HR) with 95% confidence intervals (CIs).
Results: Elderly patients with glioblastoma who underwent initiation of RT < 20 days from date of surgery demonstrated improved overall survival (OS) in our cohort (p = 0.0278). Patients who initiated RT < 18 days from date of surgery demonstrated improved progression free survival (PFS). RT fractionation scheme consisting of either hypofractionated radiation therapy (HFRT), 40 Gy in 15 fractions or conventionally fractionated radiation therapy (CFRT), 60 Gy in 30 fractions, did not affect the impact of initiation of RT on survival outcomes. Multivariate analysis demonstrated that adjuvant temozolomide significantly impacted both OS (p = 0.0118) and PFS (p = 0.0175).
Conclusion: Early initiation of RT in elderly patients with newly diagnosed glioblastoma improves both overall survival and progression free survival. The significant positive association between early initiation of RT and OS was retained after accounting for potential confounding factors. Timing of RT is particularly of significance in this patient population who may not be optimal candidates for systemic chemotherapy.