Brain cancer types & causes
Brain cancer causes abnormal growths called tumours.
These are usually classed as primary or secondary. A primary cancer is the centre of the cancer, requiring treatment to stop the cancer spreading to the spinal cord and other parts of the body.
Secondary tumours are growths that have already spread from the primary cancer site, for example from the lungs.
Cancer describes malignant tumours, which can grow aggressively.
Primary brain cancers
The brain is made up of many different types of cells.
- Some brain cancers occur when one type of cell transforms from its normal characteristics. Once transformed, the cells grow and multiply in abnormal ways.
- As these abnormal cells grow, they become a mass, or tumour.
- Brain tumours that result from this transformation and abnormal growth of brain cells are called primary brain tumours because they originate in the brain.
- The most common primary brain tumours are gliomas, meningiomas, pituitary adenomas, vestibular schwannomas, and primitive neuroectodermal tumours (medulloblastomas). The term glioma includes astrocytomas, oligodendrogliomas, ependymomas, and choroid plexus papillomas.
- Most of these are named after the part of the brain, or the type of brain cell, from which they arise.
Metastatic brain cancer
Metastatic brain tumours are made of cancerous cells from a tumour elsewhere in the body. The cells spread to the brain from another tumour in a process called metastasis. About 25% of tumours elsewhere in the body metastasise to the brain.
Brain cancer causes
As with tumours elsewhere in the body, the exact cause of most brain tumours is unknown. Genetic factors, various environmental toxins, radiation, and cigarette smoking, have all been linked to cancers of the brain, but in most cases, no clear cause can be shown.
Brain cancer scans
MRI Brain Cancer Picture: Side view section through the brain of a young girl. The white arrow shows a brain tumour that involves the brainstem.
MRI Brain Cancer Picture: Cross-section (image taken from the top of the head down) of a brain tumour in a young girl. The white arrow shows the tumour.