Effect of age on treatment decisions in low-grade glioma

Abstract

The proper treatment of low-grade glioma is unclear and major uncertainties include the timing of therapy, the need for extensive surgery, or the application of radiotherapy. Although prospective trials are in progress, it may be years before results become available, as the five-year survival of low-grade glioma is around 45% or more. Age is an important prognostic factor in malignant glioma, but its implications for decisions on treatment have not yet been addressed in guidelines. This review examines the interaction between age and the results of applied treatment, based on data from published series. The available evidence suggests that, in younger patients, whether treatment is started early or late does not seem to affect long-term survival substantially. For patients under 35 years of age, more radical surgery appears to be beneficial, while radiation does not seem to improve the outcome. For patients who are 35 years and older, surgery and radiotherapy seems to produce better survival rates. The age of the patients should therefore be considered when decisions on the treatment of supratentorial, non-pilocytic, low-grade gliomas. For patients under 35 years of age who have either epilepsy or a surgically inaccessible tumour, it is advisable to defer treatment. The tumour should be largely excised, if possible. Following any surgery, radiotherapy should be withheld in this age group. For patients over 35 years of age, early treatment, including biopsy or surgery followed by radiotherapy, should not be delayed. Because of more prolonged survival, and to prevent neurotoxicity, radiation fields should be limited to the tumour bed and not include the whole of the brain. Future trials need to establish whether age is a crucial factor in deciding the timing and extent of treatment in patients with low-grade glioma.