What is a brain tumour?
A brain tumour is a mass of abnormal cells growing in the brain. A tumour that starts in the brain is a primary brain tumour – these rarely metastasise (spread) outside the brain and spinal cord.
Benign tumours consist of very slow growing cells, usually have distinct borders and rarely integrate into the surrounding healthy brain. Treatment and/or surgery are often effective; however, a benign tumour located in a vital area of the brain, such as the central nervous system, is life-threatening.
Malignant brain tumours are the most common cancer of the central nervous system that arise without any previous history of low-grade disease and, in the majority of patients, there is no known familial genetic abnormality. Despite treatment that combines surgery, radiotherapy and chemotherapy, malignant brain tumours remain incurable. Three biological features account for the dismal prognosis associated with these tumours: cells from the main tumour mass invade the surrounding normal brain making complete surgical removal impossible; the presence of therapy-resistant tumour cells allows the initiation of tumour re-growth after therapy; and malignant tumour cells multiply rapidly.
Despite more than half a century of research into brain tumours, they remain a leading cause of death in the western world. To date, little progress has been made in understanding how tumours form, survive and grow.