A malignant brain tumour is a fast-growing cancer that spreads to other areas of the brain and spine.

Generally, brain tumours are graded from 1 to 4, according to their behaviour, such as how fast they grow and how likely they are to grow back after treatment. A malignant brain tumour is either grade 3 or 4, whereas grade 1 or 2 tumours are usually classed as benign or non-cancerous. 

Most malignant tumours are secondary cancers, which means they started in another part of the body and spread to the brain. Primary brain tumours are those that started in the brain.

These pages focus on high-grade brain tumours. For information about grade 1 or 2 tumours, read our pages on low-grade (benign) brain tumours.

Signs and symptoms

The symptoms of a malignant brain tumour depend on how big it is and where it is in the brain.

Common symptoms include:

  • severe, persistent headaches
  • seizures (fits)
  • persistent nausea, vomiting and drowsiness
  • mental or behavioural changes, such as memory problems or changes in personality
  • progressive weakness or paralysis on one side of the body, vision problems, or speech problems

See your GP if you have persistent symptoms of a brain tumour. While it's unlikely to be a tumour, it's best to be sure by getting a proper diagnosis.

Read more about the symptoms of malignant brain tumours and diagnosing malignant brain tumours.

Types of malignant tumours

Most malignant brain tumours develop from the glial tissue, which supports the brain's nerve cells. These tumours are known as gliomas.

Gliomas can be separated further, depending on the cells they developed from. For example:

  • an astrocytoma develops from cells thought to provide the brain's framework
  • an oligodendroglioma develops from the cells that produce the fatty covering of nerves
  • an ependymoma develops from the cells that line the cavities in the brain  

It's also possible to have a malignant tumour that's a mixture of these types or developed in a different part of the brain.

Who is affected

Brain tumours can affect people of any age, including children, although they tend to be more common in older adults.

Around 5,000 people are diagnosed with a primary malignant brain tumour in the UK each year. Many others are diagnosed with secondary tumours.

The exact cause of primary malignant brain tumours is unknown, although it's thought that certain genetic conditions and previous radiotherapy treatment to the head may increase the risk of one developing.

Read more about the causes of malignant brain tumours.

How malignant brain tumours are treated

A primary malignant brain tumour needs to be treated as soon as possible, because it can spread and damage other parts of the brain and spinal cord.

Surgery will usually need to be carried out to remove as much of the tumour as possible. This may be followed by radiotherapy and/or chemotherapy to kill any cancerous cells left behind and reduce the chances of the tumour regrowing.

However, malignant tumours will often eventually return after treatment. If this happens, or if you have a secondary tumour, a cure isn't usually possible and treatment can instead be used to improve symptoms and prolong life.

Read more about treating malignant brain tumours.

Living with a brain tumour

Living with a brain tumour is not easy. You may feel worried and anxious about what's going to happen to you and your family. This is perfectly normal.

It can help to seek accurate medical information about your specific tumour and its treatment, make sure you're closely involved in decisions about your care, and ask your care team about anything you're not sure about.

Your doctor may be able to refer you to a counsellor if you want to talk about the emotional aspects of diagnosis and treatment. There are also many organisations and helplines that can help, such as The Brain Tumour Charity and Brain Tumour Research.

Read more about living with a brain tumour.

Recovery and outlook

The outcome for malignant primary brain tumours depends on a number of things, such as the type and location of the tumour, your age, and how ill you were when diagnosed.

Overall, around 40% of people live at least a year, about 19% live at least five years, and around 14% live at least 10 years.

If treatment is successful, you may still be left with some persistent problems, such as seizures, walking difficulties, or speech problems. You may need supportive treatment to help you recover from or adapt to these problems.

You'll also need regular follow-up appointments to check if the tumour has started to come back.

Read more about recovering from treatment for a malignant brain tumour.

Brain tumours in children

This topic covers malignant brain tumours in general and applies to both adults and children.

Macmillan has specific information about brain tumours in children, including medulloblastoma – a brain tumour that mainly affects children.

Children's Cancer and Leukaemia Group also has a useful page about medulloblastoma and its treatment.

Page last reviewed: 19/03/2015

Next review due: 19/03/2017