Chemotherapy for diffuse low-grade gliomas

Abstract

Diffuse low-grade gliomas are rare tumors. Therapeutic strategies have dramatically changed in recent years, thanks to observational data, insight of some authors, retrospective studies, and, incidentally, results of few phase III and II trials. Surgery has become the cornerstone of the treatment. Radiotherapy, because of its potential delayed neurotoxicity and the equivalent results in terms of survival whatever the timing of the treatment (early or late), is increasingly offered to patients with unresectable tumors (or tumor that cannot be reoperated) and in case of progression after chemotherapy. Chemotherapy, subject of this chapter, has shown clinical benefits regarding tumor progression for nonsurgical patients, before or after radiotherapy: initial chemosensitivity almost constant, improvement of epilepsy and thus of cognition, and preservation of quality of life (despite a possible transient alteration). Its articulation with surgery has been more recently discussed by allowing, thanks to tumor shrinkage, subtotal or total resection (whose impact on anaplastic transformation and survival has been demonstrated), in addition to potential effects on cerebral plasticity. It remains to show the direct or indirect impact on survival, to refine its risk-benefit ratio, especially in the context of prolonged treatment with temozolomide, and to develop further research from a neurological (impact on plasticity) and oncological (involved molecular pathways, identifying new therapeutic targets) points of view.