Gliomas are the most common type of malignant brain tumour and comprise a heterogeneous group of neoplasms that differ in location within the central nervous system, in age and sex distribution, in growth potential, in extent of invasiveness, in morphological features, in tendency for progression, and in response to treatments. They develop from the glial cells that support the nerve cells of the brain and spinal cord. There are four main types: astrocytoma, ependyoma, oligliodendroglioma, and mixed tumours. Gliomas are graded according to their proliferative potential, from grade 1 to grade 4 (WHO 2000). Grades 3 and 4 – collectively referred to as glioblastoma – are considered high-grade gliomas.
Only modest advancements in the treatment of glioblastoma have occurred in the past 25 years. Although current therapies remain palliative, they have been shown to prolong quality survival. Without therapy, patients with glioblastoma multiformes uniformly die within 3 months. Treatment usually consists of surgical resection (where possible), followed by radiotherapy. Complete surgical resection of these tumours is rarely possible; expert opinion suggests a large proportion of cases will go on to relapse after first- and second-line treatment. Patients treated with optimal therapy, including surgical resection, radiation therapy, and chemotherapy, have a median survival of approximately 12 months, with fewer than 25% of patients surviving up to 2 years and fewer than 10% of patients surviving up to 5 years.