Innv-10. gliomas in adolescents and young adults – experience of cases presented at national aya multi-disciplinary rounds

Abstract INTRODUCTION Gliomas are the most common brain tumor in adolescents and young adults (AYA). IDH mutations are common in this population, though up to 30% of gliomas in AYA harbor a pediatric-type alteration including alterations in RAS/MAPK pathway and histone mutations. These can present a diagnostic and management dilemma in young adults given the limited data in this population. Here, we aim to describe glioma cases submitted for multi-disciplinary AYA rounds. METHODS Gliomas presented at the Canadian AYA Neuro-Oncology Network (CANON) rounds between April 2021 and June 2023 were compiled. Patient demographics, tumor histology and molecular alterations are described. Recommendations and themes from the multi-disciplinary rounds were summarized. RESULTS Of 132 cases presented, 96 were gliomas. Median age was 28 years (range 15-59). Twelve (12.5%) cases were IDH-mutant. Remaining cases included low grade glioma (LGG, n=37, 38.5%), IDH-WT high grade gliomas (HGG, n=22, 22.9%) and diffuse midline glioma (n=13, 13.5%). Of the LGGs, 13 gliomas had FGFR-alteration, 9 had BRAF-alteration, 3 had NF-1 with 4 having rare alterations typically seen in children (KRAS, NTRK fusion, PDGFRa K385-mut). Recommendations included discussion to start targeted therapy or management of toxicities due to targeted inhibitors in 16 cases. Of the HGGs, 7 (31.8%) had underlying cancer predisposition syndrome (NF-1 n=4, mismatch repair deficiency n=3). Management questions included role of re-resection, timing of radiation, duration of targeted therapies and access to targeted agents through clinical trials or compassionate access programs. CONCLUSION Within national rounds, there was enrichment of pediatric-type tumors and patients with cancer predisposition syndromes. Targeted agents are available for many of these driver mutations with potential improved outcomes; however, access to these agents in AYA may be limited. Clinicians face complex management questions in this population and underscores the need for a multi-disciplinary approach along with clinical trial opportunities for these patients.