Treatment Strategies for Low-Grade Glioma in Adults

Diffuse low-grade gliomas include oligodendrogliomas and astrocytomas. The recent 2016 WHO classification has now updated the definition of these tumors to include molecular characterization, including the presence of isocitrate dehydrogenase mutation and 1p/19q codeletion. In this new classification, the histologic subtype of grade II mixed oligoastrocytoma has been eliminated. Treatment recommendations are currently evolving, mainly because of a change in the prognostic factors that are based on molecular and cytogenetic features. Standard of care includes maximal safe surgical resection. Prior randomized clinical trials stratified treatment arms on the basis of extent of resection and age, with patients stratified into low risk (age younger than 40 years and gross total resection) and high risk (age older than 40 years or subtotal resection). Patients who are low risk may undergo routine magnetic resonance imaging surveillance after resection. On the basis of recently published data, it is now recommended that high-risk patients undergo a combination of both radiation and chemotherapy after surgery. These studies, however, do not address the management of patients with low-grade gliomas in the era of genomic medicine. These treatments can also have great impact on quality of life, and therefore treatment recommendations should be done on an individual basis taking into account the current pathology classification, age, extent of resection, quality of life, and patient preference.