About brain tumours

A brain or spinal cord tumour starts when abnormal cells grow and form a mass or a lump. The tumour may be benign or malignant, but both types can be serious and may need urgent treatment. Brain and spinal cord tumours are also called central nervous system or CNS tumours.

Learn more about:

• What is a tumour?
• The brain and spinal cord
• Who gets brain or spinal cord tumours?
• What types of tumours are there?
• What causes brain or spinal cord tumours?

What is a tumour?

A tumour is an abnormal growth of cells. Cells are the body’s basic building blocks – they make up tissues and organs. The body constantly makes new cells to help us grow, replace worn-out tissue and heal injuries.

Normally, cells multiply and die in an orderly way, so that each new cell replaces one lost. Sometimes, however, cells become abnormal and keep growing. In solid cancers, such as a brain tumour, the abnormal cells form a mass or lump called a tumour.

How are brain tumours classified?

Brain tumours are often classified as benign or malignant. These terms are also used for tumours in other parts of the body. But with brain tumours the difference is not as clear.

Benign tumours

Benign brain tumours usually grow slowly and are unlikely to spread. A benign tumour may grow and affect how the brain works. This can be life-threatening and may need urgent treatment. Sometimes a benign tumour can change over time and become malignant.

Malignant tumours

A malignant brain tumour may be called brain cancer. Some malignant brain tumours grow slowly, while others grow rapidly (see Grading tumours). They are considered life-threatening because they may grow larger, spread within the brain or to the spinal cord, or come back after treatment.

Primary cancer

A cancer that starts in the brain is called primary brain cancer. It may spread to other parts of the nervous system. Unlike other malignant tumours that have the potential to spread throughout the body, primary brain cancers usually do not spread outside the brain and spinal cord.

Secondary cancer

Sometimes cancer starts in another part of the body and then travels through the bloodstream to the brain. This is known as a secondary cancer or metastasis. The cancers most likely to spread to the brain are melanoma, lung, breast, kidney and bowel. A metastasis keeps the name of the original cancer. For example, bowel cancer that has spread to the brain is still called metastatic bowel cancer, even though the person may be having symptoms because cancer is in the brain.

The brain and spinal cord

The brain and spinal cord make up the central nervous system (CNS). Together, the different parts of the CNS control how the mind and body work.

The brain – The brain receives and interprets information carried to it by nerves from the sensory organs that control taste, smell, touch, sight and hearing. It also sends messages through nerves to the muscles and organs. The brain is responsible for memory, personality and behaviour. The main parts of the brain are the cerebrum, the cerebellum and the brain stem (see Parts of the brain).

Spinal cord – The spinal cord extends from the brain stem to the lower back. It is made up of nerve tissue that connects the brain to all parts of the body through a network of nerves called the peripheral nervous system. The spinal cord lies in the spinal canal, protected by a series of bones (vertebrae) called the spinal column.

Meninges – These are thin layers of protective tissue (membranes) that cover both the brain and spinal cord.

Cerebrospinal fluid (CSF) – Found inside the skull and spinal column, CSF surrounds the brain and spinal cord and protects them from injury.

Pituitary gland – This is found at the base of the brain and is about the size of a pea. The pituitary gland makes chemical messengers (hormones) and releases them into the blood. These hormones control many body functions, including growth, metabolism and development.

The central nervous system

The parts of the brain

The largest part of the brain is the cerebrum. It is divided into two halves called hemispheres. Each hemisphere is divided into four main areas – the frontal, parietal, occipital and temporal lobes.

The other main parts of the brain are the cerebellum and the brain stem. The cerebellum is found at the back of the head. The brain stem connects the brain to the spinal cord. Each part of the brain controls different bodily functions.

Top view

Side view

Who gets brain or spinal cord tumours?

Every year an estimated 1900 malignant brain tumours are diagnosed in Australia. They are more common in men than women, and can affect people of any age. About 100 children aged 0–14 are diagnosed each year.

Benign brain and spinal cord tumours are more common than malignant tumours. Data is not collected by every Australian state, but in 2017 there were more than 1200 benign brain and spinal cord tumours in Victoria, Queensland and Western Australia combined.

What types of tumours are there?

The brain is made up of different tissues and cells, which can develop into different types of tumours. There are more than 40 types of primary brain and spinal cord tumours. They can start in any part of the brain or spinal cord. Tumours are classified based on the type of cell they start in and how the cells are likely to behave (based on their genetic make-up). Gliomas are the most common type of malignant brain tumour.

Common types of primary brain tumours

Glioma tumours

These tumours start in the glial (neuroglia) cells of the brain.

Non-glioma tumours

These tumours start in other types of cells found in the brain.

What causes brain or spinal cord tumours?

The causes of most brain and spinal cord tumours are unknown, but things known to increase a person’s risk include:

Family history – While it is rare for brain tumours to run in families, some people inherit a gene change from their mother or father that increases the risk of developing a brain tumour. For example, some people have a genetic condition called neurofibromatosis, which can lead to mostly benign tumours of the brain and spinal cord.

Radiation therapy – People who have had radiation therapy to the head, particularly to treat childhood leukaemia, may have a slightly higher risk of developing a brain tumour, particularly meningioma.

Chemical exposure – A chemical called vinyl chloride, some pesticides, and working in rubber manufacturing and petroleum refining have been linked with brain tumours.

→ READ MORE: Brain cancer symptoms