What is a brain or spinal cord tumour?
A brain or spinal cord tumour occurs when cells in the central nervous system grow and divide to form a lump. Tumours can be benign or malignant.
Benign (non-cancerous) tumours – Benign tumours usually have slow-growing cells and rarely spread. However, they may press on the brain, spinal cord, or the cranial nerves, and cause symptoms. Benign tumours may be found in areas of the brain that control vital life functions, and require urgent treatment.
Malignant (cancerous) tumours – These life-threatening tumours often grow rapidly, and may spread within the brain and spinal cord, or reoccur even after treatment. Just over 40% of all brain and spinal cord tumours are malignant.
Topics on this page:
- The brain and spinal cord
- Types of brain and spinal cord tumours
- Who gets brain or spinal cord tumours?
- What causes brain or spinal cord tumours?
- Video: What is brain cancer?
The brain and spinal cord
The brain and spinal cord make up the central nervous system (CNS). The CNS receives messages from cells called nerves, which are spread throughout the body.
The brain – Interprets information and relays messages through the nerves to muscles and organs. The main parts of the brain are:
- the cerebrum – the largest part
- the cerebellum
- the brain stem
- the pituitary gland – this is deep within the brain, controls growth and development by releasing chemical messengers (hormones) into the blood. These chemical messengers signal other hormones to start or stop working.
The spinal cord – This extends from the brain stem to the lower back. It consists of nerve cells and nerve bundles that connect the brain to all parts of the body through the peripheral nervous system. The spinal cord lies in the spinal canal, and is protected by bony vertebrae (spinal column).
Meninges – This is the membrane that surrounds both the brain and spinal cord.
Cerebrospinal fluid (CSF) – This is the liquid in which the brain and spinal cord float in inside the skull and vertebrae.
The brain, spinal cord and nerves consist of billions of nerve cells called neurons or neural cells, which process and send information. Together this is called nervous tissue.
The three main types of neural cells are:
- sensory neurons – respond to light, sound and touch
- motor neurons – cause muscle contractions
- interneurons – connect neurons in the brain and spinal cord.
Glial cells, or neuroglia, are the other main type of cells in the nervous system. There are several different types of glial cells, including astrocytes and oligodendrocytes. Glial cells surround the neurons and hold them in place. The glial cells also supply nutrients to neurons and clear away dead neurons and germs.
What the brain does
The brain plays a unique role in the body’s essential functions. The brain controls all voluntary and involuntary processes, such as moving, learning, sensing, imagining, remembering, breathing, blood circulation and heart rate, body temperature, digestion, and bowel and bladder control (continence).
The cerebrum is divided into right and left hemispheres. The right hemisphere controls muscles on the left side of the body, and the left hemisphere controls muscles on the right side. The hemispheres are connected by a band of nerve fibres known as the corpus callosum, which transfers information between the two hemispheres.
Each hemisphere is divided into four main areas, called lobes – frontal lobe, parietal lobe, occipital lobe and temporal lobe. These control different functions.
Types of brain and spinal cord tumours
There are more than 100 types of brain and spinal cord tumours (also called central nervous system or CNS tumours). They are usually named after the cell type they started in.
The most common types include:
- pituitary tumours – grow from the pituitary gland)
- meningiomas – grow from the meninges
- neuromas – grow from the nerves
- pilocytic astrocytomas – grow in the cerebellum.
Gliomas – These are the most common type of cancerous brain tumours in adults and children.
There are three types of gliomas: astrocytomas, oligodendrogliomas and ependymons.
Gliomas can be classified as low or high grade depending on how fast they are growing. A common high grade glioma is glioblastoma (also known as glioblastoma multiforme or GBM), a type of astrocytoma.
Medulloblastomas – Another type of malignant tumour, which develop in the cerebellum. These are rare in adults but common in children.
Metastatic brain tumours
Metastatic brain tumours are secondary brain tumours that begin as a primary cancer in another part of the body before spreading to the brain.
Cancers that may spread to the brain include melanoma, bowel, breast, kidney and lung cancer.
Who gets brain or spinal cord tumours?
Every year about 1700 malignant brain tumours are diagnosed in Australia.
The most common type in adults is a type of glioma called glioblastoma multiforme or GBM. These tumours are generally found in the cerebral hemispheres.
Malignant spinal cord tumours are rare. About 80 people are diagnosed with malignant spinal cord or central nervous system tumours each year.
Data about benign brain and spinal cord tumours is not collected, but they are more common than malignant tumours. In Australia, an estimated 2350 people – including children – are diagnosed with a benign tumour each year.
Childhood brain tumours
In Australia, about 130 children under 15 are diagnosed with a brain tumour each year. Around 80% of these are cancerous.
Children are more likely to develop tumours in the lower parts of the brain, the area that controls movement and coordination.
Glioma and medulloblastoma are the most common types. About 20 children are diagnosed with a spinal cord tumour each year. If your child has a brain tumour, see Caring for a child with a tumour.
What causes brain or spinal cord tumours?
The causes of most brain and spinal cord tumours are unknown. However, there are a few known risk factors for malignant brain tumours:
- Family history – It is possible to have a genetic predisposition to developing a tumour. This means that you may have a fault in your genes, usually passed down from one of your parents, that increases your risk. For example, some people have a genetic condition called
neurofibromatosis, which causes nerve tissue tumours.
- Radiotherapy – People who have had radiation to the head, usually to treat another type of cancer, may be at an increased risk of developing a tumour. This may affect people who had radiotherapy for childhood leukaemia.
Electromagnetic radiation and brain cancer
Many people are concerned that mobile phones or microwave ovens may cause brain cancer.
Evidence to date does not show that mobile phone use causes cancer. However, if you are concerned about potential harm from mobile phones, you may choose to use a headset, limit the time you spend on your mobile phone or consider texting rather than calling. Additionally, you could consider limiting your child’s mobile phone use.
Microwave ovens have been in widespread use since the 1980s. There is no evidence that ovens in working order emit electromagnetic radiation at levels harmful to humans.