Patterns of care and outcomes in pediatric high-grade glioma patients enrolled in the pediatric proton/photon consortium registry

Abstract BACKGROUND Proton therapy (PRT) is increasingly utilized for pediatric brain tumors to reduce radiation associated treatment effects, but there is a lack of data evaluating PRT in pediatric high-grade glioma (pHGG). The purpose of this analysis is to report patterns of care and clinical outcomes for pHGG patients treated with PRT and enrolled in the prospective Pediatric Proton/Photon Consortium Registry (PPCR). METHODS Fifty-five pHGG participants treated with PRT were enrolled in the PPCR between Jan 2013 and Aug 2020. Progression free (PFS) and overall survival (OS) rates were calculated according to the Kaplan-Meier method. Univariate analyses were performed using Cox proportional hazards model with Firth’s penalization. RESULTS Among 49 patients with complete data, the median age was 12, the majority of patients were male (29), white (35), and non-Hispanic/Latino (41). Histology was grade IV (37), grade III (10) or HGG not specified (8). Resection was gross-total (24), near-total (4), or sub-total/biopsy (17). Six patients received prior RT. The median RT dose was 57.6 Gy (RBE) starting a median of 33.5 days after surgery. 39 patients received chemotherapy. The most common acute treatment toxicities were alopecia (36), fatigue (34), radiation dermatitis (22), nausea/vomiting (19), and headache (19). Median follow-up was 3.14 years (95% CI 1.62-3.97). At 3 years, PFS (95% CI) was 35.5% (20.8-50.6%) and OS was 55.6% (38-70%). Median PFS and OS are 1.6 (1.2-3.1) and 3.6 (1.6-NA) years, respectively. Higher radiation dose was associated with greater PFS (HR 0.97 (0.94-1.01), p=0.059) and OS (HR 0.95 (0.93-0.99), p=0.006). Patients ≤ 3 years at diagnosis (n=8) had 3-year PFS/OS of 72.9%/87.5% vs. 27.8%/49.4% for older patients (p=0.068/0.089, respectively). CONCLUSION These are the first published data with PRT for pHGG. Clinical outcomes are comparable to historical data with photon therapy. Additional analysis of treatment associated toxicity and patient quality-of-life are warranted.