Low-grade gliomas in adults

Abstract

This paper aims to summarize the current thinking about the management of adult supratentorial low-grade gliomas. These are well differentiated primary brain tumours that typically develop in young adults. Their biological behaviour is poorly understood but the majority of these tumours grow slowly, infiltrate surrounding normal brain, and show an intrinsic tendency to undergo malignant transformation to high-grade gliomas. Surgery and radiotherapy are the main treatment options, but their precise role and timing are controversial.

Resective surgery is at best regarded as a practice option because there is a paucity of good quality evidence to show that extent of resection correlates with survival. Radiotherapy prolongs progression-free survival but not overall survival and may lead to long-term cognitive deficits, although not as widespread as had previously been thought. A minority of tumours with oligodendroglial differentiation are chemosensitive and this correlates with allelic loss of chromosomes 1p and 19q. New imaging and molecular techniques, in particular gene microarray studies, are providing more information about these tumours, although they have yet to have a significant impact on clinical management.

The best management of low-grade gliomas is still unknown but advances in molecular genetics and imaging are improving our ability to prognosticate and follow the natural history of these tumours.