158 - Low-Grade Gliomas: Diffuse Astrocytoma and Oligodendroglioma

Abstract

Diffuse low-grade gliomas (WHO grade II) include oligodendroglioma and diffuse astrocytoma that are common primary CNS tumors affecting predominantly young adults. Diagnostic classification and prognosis for these tumors is now dictated by the combination of both histologic and molecular features. Diffuse low-grade gliomas in adults are genetically defined by a recurrent oncogenic mutation in either the IDH1 or IDH2 genes, with diffuse astrocytomas harboring accompanying TP53 and ATRX mutations, and oligodendrogliomas harboring accompanying TERT promoter mutation and co-deletion of chromosomes 1p and 19q. Following radiographic characterization, maximal resection remains a cornerstone of patient management. Greater extent of resection and smaller volume of residual tumor positively affects overall survival and progression-free survival. Temozolomide and radiotherapy lengthen survival for high-risk patient populations. This chapter focuses on the management of WHO grade II diffuse gliomas in adults including diagnostic classification and therapeutic strategies such as cytoreductive surgery, radiotherapy, and chemotherapy.