Pediatric high-grade glioma: a review of biology, prognosis, and treatment

The incidence of high-grade gliomas (HGGs) in children is significantly lower than in adults, with less than 400 children diagnosed every year in the USA. While the histopathology of HGGs in children is very similar to those in adults, their biology is very different. Recent studies have led to an exponential increase in our understanding of the biology of these tumors, with the identification of distinct epigenetic subtypes, each with characteristic clinical and molecular profiles. The 2016 WHO classification of central nervous system tumors has recognized the most common subtype, with the poorest prognosis-"diffuse midline glioma H3 K27M-mutant"-marking a shift towards the integration of molecular features with the traditional histopathological diagnosis. Like adults, children with HGGs have a very poor prognosis overall, with treatment consisting of maximal safe surgical resection followed by radiation therapy. However, the role of temozolomide, which is a well-established adjuvant therapy for MGMT-methylated HGGs in adults, is less clear in children. In this review, we outline the epidemiology, recent advances in our understanding of biology, past landmark clinical trials, and promising therapeutic strategies for pediatric HGG.