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A brain tumour is a growth of cells in the brain that multiply in an abnormal, uncontrollable way. However, it is not always cancerous.
Brain tumours are graded from 1 to 4 according to their behaviour, such as how fast they grow and how likely they are to spread.
Benign brain tumours (non-cancerous)
Generally, low-grade brain tumours – grade 1 or 2 – are slow growing and unlikely to spread. They are usually benign (non-cancerous), which means they tend to stay in one place and do not invade other areas of the brain or spread to other parts of the body.
Sometimes, they can be surgically removed and will not come back, causing no further problems. But some grade 2 tumours may grow back.
Read our pages on benign brain tumours for more information on low-grade brain tumours, including the symptoms, treatment and recovery.
Malignant brain tumours (cancerous)
Malignant brain tumours can be either primary or secondary. Most common malignant brain tumours are spread to the brain from tumours outside the brain (secondary tumours) and treatment aims to prolong life and relieve the symptoms.
Primary malignant tumours, or high-grade brain tumours (grade 3 or 4) which start in the brain, are generally fast-growing. These must be treated as soon as possible to prevent them spreading to, and damaging, other parts of the brain and spinal cord.