OP02
ADOLESCENT/YOUNG ADULT MEDULLOBLASTOMA: TIME FOR A CHANGE IN MANAGEMENT STRATEGY Free

INTRODUCTION: About 20% of medulloblastoma cases arise between 15 and 40 years of age, representing only 1% of adult brain tumors. No prospective randomized trials of treatment for adults have ever been reported; however, retrospective reports in the modern era (Carrie 2007) suggest no outcome differences with lower craniospinal irradiation (CSI) doses (<34Gy) with chemotherapy versus higher CSI doses (>34Gy) alone (77 and 62% 5 and 10 year overall survival). These outcomes appear inferior to those currently reported in children with standard-risk medulloblastoma; however, these populations are now recognized to be dissimilar clinically, histologically and molecularly, with metastases, anaplastic/large cell histology and cmyc amplification (Group C) being very uncommon at diagnosis in adult patients (Kool 2012). Further, SHH tumors appear more prevalent in adults, except for the youngest children, and display distinct molecular differences. METHOD: We propose a multi-center prospective randomized trial of 36Gy CSI with tumor bed boost (18Gy) with or without an attenuated maintenance chemotherapy regimen for older adolescents/adults newly-diagnosed with non-metastatic medulloblastoma. Central review of imaging studies, histopathology and quality of life assessments will be mandated. Submission of paraffin-embedded tumor tissue and blood for sub-group classification, methylation profiling and whole exome sequencing, will be performed in order to create a correlational biobank to parallel the first prospective dataset in this population. CONCLUSION: This prospective, randomized clinical trial will set a new “benchmark” for diagnosis, prognostication and treatment of adults with medulloblastoma