Stereotactic Radiosurgery for Recurrent High-grade Glioma

Introduction: Patients with high-grade gliomas (WHO Grades III and IV HGGs) have high tumor recurrence rates, yet treatment for recurrence remains ill-defined. Gamma Knife stereotactic radiosurgery (GKRS) is a non-invasive, highly conformal radiation therapy procedure, which makes it suitable for smaller lesions difficult to access through standard neurosurgical resection and thus a potential solution given HGGs’ infiltrative nature and better radiosurgical response. Our aim was to evaluate the role of GKRS in treating high-grade glioma (HGG) recurrence and look into how modifiable risk factors such as nutrition and frailty statuses can influence patient outcomes.

Methods: We conducted a retrospective chart review of 43 patients with recurrent HGGs who were treated with GKRS in the Allegheny Health Network in Pittsburgh, PA from January 2020 to June 2024. Pre-GKRS Prognostic Nutritional Index (PNI) and 5-factor modified frailty index (mFI-5) scores were calculated for each patient. Descriptive statistics were calculated in Excel. Survival analysis was performed with the Kaplan-Meier method using RStudio. Univariate and multivariate analyses were performed using Cox proportional hazard models.

Results: The median overall survival (OS) was 7.7 months (95% CI: 6.3-9.9 months) and median progression-free survival (PFS) was 5.4 months (95% CI: 3.8-7.2 months). There was no difference in survival between pre-frail (mFI=0-2) and frail subgroups (mFI>2) (P=0.99) nor a difference in survival between sufficient nutrition status (PNI>45) and poor nutrition status subgroups (PNI < 45) (P=0.50). Patients with IDH-1 mutations and MGMT promoter methylation had longer OS and PFS.

Conclusion : Patients with IDH-1 mutations and MGMT promoter methylation had better survival post-GKRS. There was no significant difference in survival in regard to nutritional and frailty statuses for patient outcomes post-GKRS. Future directions include studying a larger cohort and intervening on pre-procedural risk factors.