What is a Brain Tumour?
Up to 40% of all cancers spread to the brain
Most commonly brain tumours develop from cells that support the nerve cells of the brain. These are called glial cells and a tumour of glial cells is called a glioma.
Brain tumours can also be named after the area they are growing in. For example, a tumour of the pituitary gland is called a pituitary adenoma and a tumour developed from the covering of the brain (the meninges) is called a meningioma.
In adults the most common tumour types are gliomas (astrocytoma) and meningiomas Brain tumours are the leading cause of cancer-related death in patients under the age of 40. In adults, incidence is generally highest between the ages of 40 to 60.
In children, incidence is generally highest before the age of 1 and again between ages 2 and 12. The most common types of brain tumour in children are astrocytomas, medulloblastomas, ependymomas and brain stem gliomas.
Brain tumours are either termed as:-
benign or low-grade (I or II), meaning
- The tumour is relatively slow growing
- It is less likely to come back if it is completely removed
- It is not likely to spread to other parts of the brain or spinal cord
- It may just need surgery and not radiotherapy or chemotherapy
- Some benign tumours may re-grow at a slow rate and further surgery or radiotherapy may be necessary
- If the tumour’s position means that surrounding tissue could be damaged by surgery, removal may not be possible
malignant or high-grade (III or IV), meaning
- The tumour is life-threatening and relatively fast growing
- It is likely to come back after surgery, even if completely removed
- It may spread to other parts of the brain or spinal cord
- It cannot just be treated with surgery and will need radiotherapy or chemotherapy to try to stop it from coming back
primary brain tumours, meaning
the tumour originates in the brain
secondary brain tumours, meaning
secondary or metastatic means that the tumour began to grow in another part of the body and then spread to the brain through the bloodstream. When tumours spread to the brain, they normally go the part of the brain called the cerebral hemispheres or to the cerebellum. Often a patient may have several metastatic tumours in different parts of the brain as do certain skin cancers. Metastatic brain tumours may be quite aggressive and may return even after surgery, radiotherapy and chemotherapy. In adults secondary brain tumours are the most common type of brain tumours.
General information on high-grade and low-grade brain tumours is available from NHS Choices.