What is a brain tumour?

A brain tumour is a lump in the brain which is caused when brain cells divide and grow in an uncontrolled way. What causes brain cells to start growing and dividing differently from healthy cells, forming a 'high grade' (cancerous) or 'low grade' (benign) tumour is not yet understood.

There are over 130 different primary brain and spinal tumours which are grouped and named according to the type of cell they grow from, their location in the brain and how quickly they are likely to grow and spread.

Primary brain tumour

A brain tumour originating in the brain is known as a primary brain tumour.

Secondary brain tumour

If the tumour started somewhere else in the body e.g. the lung, then spread to the brain, it is known as a secondary brain tumour or 'metastases'. There are over 130 different primary brain and spinal tumours which are grouped and named according to the type of cell they grow from, their location in the brain and how quickly they are likely to grow and spread.

How are brain tumours graded?

Each year in the UK, approximately 4,300 people are diagnosed with low grade, slow growing brain tumours and 5,000 with high grade fast growing brain tumours. Combined, this represents less than 2 out of every 10,000 people in the UK.

Brain tumours are graded from 1 – 4 depending on how they are likely to behave.

  • Grade 1 and 2 tumours (low grade)
  • Grade 3 and 4 tumours (high grade)

Low grade

Low grade brain tumours are:

  • Slow growing
  • Relatively contained with well-defined edges
  • Unlikely to spread to other parts of the brain
  • Have less chance returning (if they can be completely removed)

High grade

High grade brain tumours are:

  • Fast growing
  • Can be referred to as 'malignant' or 'cancerous' growths
  • More likely to spread to other parts of the brain
  • May come back, even if intensively treated

Types of brain tumour

Brain tumour types can sound long and complicated as they are usually named after the type of cell they grow from and where they are in the brain.

For information on specific tumours, please see our types of brain tumour pages, which detail treatments, symptoms, types and grades of different brain tumours for adults and children.

What causes brain tumours?

Very often, the answer is that we do not know.

The risk factors that we know about are:

  • Genetics
  • Radiation

Inheriting a gene that may make you more likely to develop a brain tumour is thought to account for around one in 20 brain tumours.

Certain genetic conditions, such as neuro-fibromatosis (NF), may increase your risk of developing a brain tumour.

The risk of developing a meningioma or glioma is higher if you had radiotherapy to the head as a child, particularly before the age of five.

It is important to remember that brain tumours are nobody's fault.

The images below show normal cell division and growth and what happens when there is abnormal cell division and growth, which can lead to the development of a tumour.

Normal cell division and growth

graphic showing how normal cells divide

Abnormal cell division and growth, leading to the development of a tumour

a graphic diagram showing the process of cancer cell division

Read more about brain cells and brain tumours.

How common are brain tumours?

Over 10,600 people are diagnosed with a primary brain tumour each year. This means that 29 people in the UK are diagnosed with a brain tumour every day. It is important to note that other conditions can cause similar signs or symptoms of brain tumours, but it is important to recognise these, so you can go to your doctor if you are concerned.

How are brain tumours treated?

Your team of specialised health professionals, called the MDT (Multi-Disciplinary Team) will tailor your treatment to provide the treatment that is the best for you. They will consider factors, such as:

  • Your individual diagnosis
  • Your general health
  • Size and location of the tumour
  • Type of tumour
  • How quickly it is growing
  • Your age

This could mean that you meet other patients who have the same tumour but who are receiving different treatments.

For some low grade, slow growing tumours, you may not be given any immediate treatment at all. This is known as watch and wait

For other tumours, you are likely to receive one or more of the following types of treatment:


Surgery is often used to remove as much of the tumour as possible. This will help to reduce pressure on the brain caused by the tumour itself or by any blockages of cerebrospinal fluid. It is increased pressure that can cause some of the symptoms.

Depending on where in the brain the tumour is, surgery is not always possible or necessary.

Radiotherapy and chemotherapy

These may be used - on their own, in combination or after surgery to try to remove any remaining tumour cells.

Find further information on brain tumour treatments for adults, and brain tumour treatments for children.

Page last reviewed: 05/2014

Next review due: currently under review

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