Reviewed by:
Dr Kate Drummond, Neurosurgeon, Royal Melbourne Hospital
Dr Peter New, Head, Spinal Rehabilitation Unit, Caulfield General Medical Centre and lecturer, Monash University Departments of Medicine and Epidemiology and Preventative Medicine.
Taken from 
Brain and Spinal Chord Tumour booklet (1.3MB).
Secondary brain tumours (metastases)
Causes of brain and spinal cord tumours
How common are brain and spinal cord tumours?
The brain controls our thoughts, intelligence, memory and emotions. It coordinates body functions such as movement, blood circulation and production of hormones. It also interprets information from our senses (sight, hearing, smell, touch and taste). The average brain weighs about one and a half kilograms and is surrounded and protected by the skull.
The spinal cord connects nerves from all parts of the body with the brain. It extends from the base of the brain to just below the waist. It is about as thick as a little finger and is protected by the bones of the spinal column.
The brain and spinal cord form the central nervous system. The central nervous system is made up of nerve cells called neurones and supporting cells called glial cells. Neurones transmit messages around the body, which enable us to act when we wish (for example, to stand up and walk). They also enable functions that we are barely aware of, such as controlling digestion of food and causing the heart to beat rapidly when we exercise.
The brain and spinal cord are supported by coverings called meninges.
Tumours that start in the brain are called primary brain tumours. Some types of brain tumours are benign and some are malignant.
A benign tumour is made of slow-growing cells and is unlikely to spread. However, a benign tumour may cause problems because it takes up space inside the skull. It may press on the brain or important nerves that come out of the brain (called cranial nerves). The pressure may affect the normal function of these structures. It may raise the pressure in the skull and cause headaches and/or nausea. It is common for benign brain tumours to be treated successfully.
Types of benign brain tumours include:
Malignant tumours vary in how they grow and respond to treatment. In some malignant tumours, the cancer cells spread into the surrounding normal brain. In other malignant tumours, cancer cells can spread to other parts of the central nervous system or, rarely, other parts of the body.
The most common type of malignant brain and spinal tumour is a glioma. Gliomas grow from the supporting cells of the brain. There are different types of supporting cells and the tumours are named after the type of cell they grow from. Some types of gliomas include astrocytoma, oligodendroglioma, ependymoma and glioblastoma multiforme.
Medulloblastoma is another type of malignant tumour of the central nervous system. Other, less common malignant tumours include central nervous system lymphomas, germ cell and pineal tumours.
Tumours that start in other parts of the body can spread to the brain and/or spine and/or the meninges. These secondary tumours are called metastases. This is very common. They are not primary brain or spinal tumours but they can cause similar symptoms. This happens if they affect various parts of the brain directly or by causing pressure and distorting the nearby normal brain or spinal cord. Examples of tumours that commonly spread to the brain are lung and breast cancer.
Tumours are less common in the spinal cord than in the brain.
A tumour in the spinal cord will affect the spinal cord by pressing on it. This may stop the flow of messages along the nerves between the brain and body and can affect the control of some parts of the body. Most commonly this can cause difficulty with using the arms or legs or difficulty controlling the bladder or bowel. There may also be changes to the feeling in the skin.
Tumours may start in the spinal cord itself or grow from the coverings of the spinal cord. They can be benign or malignant. Like brain tumours, they are named for the type of cell from which they grow.
The causes of these tumours are not fully understood. Researchers around the world are investigating possible causes. We know that brain and spinal cord tumours are more common in people with certain inherited or genetic conditions. They are also more common in people exposed to very high doses of radiation. But for most people, the cause of their brain tumour is not known.
Malignant tumours of the central nervous system are diagnosed in around 400 Victorians every year.
