What is a brain tumour?

A brain or spinal cord tumour occurs when abnormal cells grow and form a mass or a lump. The brain and spinal cord are made up of two main types of cells, neurons and glial cells. 

Tumours in the brain 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. Both types can be serious and may need urgent treatment. 

• Benign brain tumours usually grow slowly and are unlikely to spread. They may also be called low-grade or non-malignant tumours. A benign tumour may grow and affect how the brain works. This can be life-threatening and may require urgent treatment. Sometimes a benign tumour can change over time and become high grade.
• Malignant brain tumours can grow rapidly. They are considered life-threatening because they may spread within the brain and spinal cord, or come back after treatment. A malignant brain tumour may be called brain cancer. Unlike malignant tumours in other parts of the body, malignant brain tumours usually do not spread outside the brain and spinal cord. 

A brain tumour that first develops in the brain is called primary brain cancer. It may spread to other parts of the nervous system, but rarely spreads to other parts of the body.

Cancer that starts in another part of the body and then travels through the bloodstream to the brain 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. 

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 the activities of the mind and body.

• The brain – receives and interprets information carried to it via nerves from the sensory organs that control taste, smell, touch, sight and hearing. It also sends messages via 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.
• 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 bony vertebrae called the spinal column.
• Meninges – thin layers of protective tissue (membranes) that cover both the brain and spinal cord.
• Cerebrospinal fluid – found inside the skull and spinal column. It surrounds the brain and spinal cord and protects it from injury.
• Pituitary gland – found at the base of the brain and is about the size of a pea. The pituitary gland releases chemical messengers (hormones) into the blood, which control many body functions, including growth and development, and also tell other glands to start or stop releasing hormones. 
  
  

Types of brain tumours

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 (also called central nervous system or CNS 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). 

Glioma tumours

This is the most common category of brain tumour. Gliomas are tumours that start in the glial (neuroglia) cells of the brain. They include:

• astrocytoma – most common type of glioma, which starts in glial cells called astrocytes
• ependymoma – starts in glial cells called ependymal cells, more common in children than adults
• glioblastoma (GBM) – a type of high-grade astrocytoma that makes up more than half of all gliomas, common in both adults and children
• oligoastrocytoma – mixed glioma tumour that contains both oligodendroglioma and astrocytoma
• oligodendroglioma – starts in glial cells called oligodendrocytes, more common in children than adults.

Non-glioma tumours

• medulloblastoma – high-grade tumour that starts in the cerebellum, more common in children and rarer in adults
• meningioma – common primary brain tumour that starts in the membranes (meninges) covering the brain and spinal cord, usually benign and slow growing
• pituitary tumour – starts in the pituitary gland, usually benign
• schwannoma – starts in Schwann cells which surround nerves in the brain, usually benign, includes acoustic neuromas.

Risk factors

The causes of most brain and spinal cord tumours are unknown, but factors known to increase the risk include:

• Family history – while it is rare for brain tumours to run in families, a fault in the genes, usually passed down from either the mother or father, can increase the risk of developing a brain tumour. 
• 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. 
  
  

Symptoms

Symptoms depend on where the tumour is in the brain or spinal cord, and how quickly it is growing. Many symptoms are likely to be caused by other factors. You should speak to your doctor about any new, persistent or worsening symptoms.

Brain tumours can increase pressure inside the skull (known as intracranial pressure), because the tumour itself is taking up too much space or because it is blocking the flow of cerebrospinal fluid around the brain. This increased pressure can lead to general symptoms such as:

• headaches – often worse when you wake up
• nausea and vomiting – often worse in the morning or after changing position (e.g. moving from sitting to standing)
• confusion and irritability
• blurred or double vision
• seizures (fits) – some jerking or twitching of your hands, arms or legs, or it can affect the whole body
• loss of consciousness
• weakness in parts of the body
• drowsiness – a later symptom.
  
  

Health professionals

Your general practitioner (GP) or another doctor will arrange the first tests to assess your symptoms. If these tests do not rule out a tumour, you will usually be referred to a specialist, such as a neurosurgeon or neurologist, who will examine you and arrange further tests.

Often these will be discussed with other health professionals at what is known as a multidisciplinary team (MDT) meeting. 

During and after treatment you will see a range of health professionals, which may include a medical oncologist, neuropathologist, rehabilitation specialist and exercise physiologist, who specialise in different aspects of your care.