A brain tumour is a growth of cells in the brain that multiplies in an abnormal, uncontrollable way.

Brain tumours are graded according to how fast they grow and how likely they are to grow back after treatment.

Grade 1 and 2 tumours are low grade, and grade 3 and 4 tumours are high grade.

There are 2 main types of brain tumours:

• Non-cancerous (benign) brain tumours – these are low grade (grade 1 or 2), which means they grow slowly and are less likely to return after treatment
• Cancerous (malignant) brain tumours – these are high grade (grade 3 or 4) and either start in the brain (primary tumours) or spread into the brain from elsewhere (secondary tumours); they're more likely to grow back after treatment

What is a primary brain tumour?

A primary brain tumour is a tumour that starts in the brain.

The brain manages how we think, feel, learn, and move. It also controls other important things in the body, such as breathing and heart rate. The brain is protected by the skull.

What is secondary brain cancer?

Secondary brain cancer is cancer that starts somewhere else in the body and spreads to the brain. It may also be called brain metastases or secondary brain tumour. It is a type of advanced cancer.

Some types of primary cancer are more likely to spread to the brain. The primary cancer is where the cancer first started.

These include:

• Lung cancer
• Breast cancer
• Bowel cancer
• Kidney cancer
• Melanoma (a type of skin cancer).

Sometimes, secondary brain cancer is found before the primary cancer has been diagnosed. For a small number of people, it is not possible to find the primary cancer. This is called secondary brain cancer from an unknown primary.