2496 - Imaging and Clinical Outcomes following Definitive Radiation Therapy for Children with High-Grade Glioma
Presenter(s)
S. Unnikrishnan1, A. Rejimon2, K. Reddy3, N. Ali4, N. Esiashvili5, and B. R. Eaton5; 1Winship Cancer Institute of Emory University, Atlanta, GA, 2Emory School of Medicine, Atlanta, GA, 3Emory University, Atlanta, GA, 4University of Rochester School of Medicine and Dentistry, Rochester, NY, 5Department of Radiation Oncology, Winship Cancer Institute of Emory University, Atlanta, GA
Purpose/Objective(s): Pediatric high-grade gliomas have a dismal prognosis despite definitive radiation therapy (RT) and novel therapies are needed. Post-RT objective response, pseudo progression, and patterns of failure vary among this heterogenous population, and there is limited data available to provide historical controls of these outcomes for future trials. The purpose of this study is to report these imaging and clinical outcomes following definitive radiation therapy among children with high-grade glioma.
Materials/Methods: This single institution retrospective analysis included children= 18 years old treated with definitive RT for a biopsy confirmed WHO grade 3-4 glioma between 2006-2023. Primary diffuse pontine gliomas were excluded. Pre- and post-treatment brain MRIs were reviewed to evaluate imaging outcomes and patterns of failure. Kaplan-Meier Estimate was used to calculate overall survival (OS) and progression-free survival (PFS). Log-rank tests were used to compare OS and PFS between groups. Chi square test was used to assess correlation between tumor location and recurrence patterns.
Results: 53 patients were included. The median age was 12 years (range 4-18 years), 72% were males, 15% had gross total resection (GTR), 26% received chemotherapy during and/or after RT. Tumors were primarily located in the cerebral hemispheres (n=28), thalamus (n=21) and posterior fossa (n=4). The median RT dose was 59.4 Gy (range 54 –60 Gy), and 25% received proton therapy. The median follow-up time was 17.3 months (range 4-108 months). Median PFS and OS was 11 and 19 months, respectively. Both PFS and OS were significantly associated with extent of surgical resection (p<0.05); median PFS and OS was 25 and 39 months following GTR vs. 11 and 18 months following sub-total resection (STR) or biopsy. No significant association between PFS or OS and RT dose or tumor location was found. 47 patients experienced tumor progression, which was infield 43% (n=23), marginal 13% (n=7), or distant 43% (n=23) from the RT field. On first post treatment follow up MRI, 57% (n=30) had stable/improved imaging, 3% (n=2) had disease progression, and 40% (n=21) had pseudoprogession, of which 7 patients (13%) with pseudoprogression had new or worsening associated symptoms.
Conclusion: Our study adds to the existing literature to provide insight into clinical and imaging outcomes for pediatric patients with high-grade glioma following definitive treatment and may serve as a reference for future clinical trials. GTR was significantly associated with longer survival. Future work including molecular characterization of these specimens for correlation with clinical and imaging outcomes is ongoing and will be included in future abstract presentations.