What are risk factors?

Doctors do not usually know the cause of a primary brain tumour. There are some things that may increase the risk of developing a brain tumour. These are called risk factors.

It is important to remember that having a risk factor does not mean you will get a brain tumour. Only a small number of people develop a brain tumour because of one of these risk factors.

Age

Brain tumours can develop at any age, but the risk is higher if you are older. A few types of brain tumour are more common in younger adults.

Gender

Brain tumours are slightly more common in men than in women.

Previous radiotherapy treatment

People who had radiotherapy to the head as children have a slightly higher risk of developing a brain tumour later in life.

Genetic conditions

It is very rare for brain tumours to run in families. A small number of inherited genetic conditions are linked to a higher risk of certain types of brain tumour. These include:

  • neurofibromatosis type 1 and type 2 (NF1 and NF2)
  • tuberous sclerosis
  • Li-Fraumeni syndrome
  • von Hippel-Lindau syndrome
  • Turcot’s syndrome
  • Gorlin syndrome
  • Cowden’s disease.

If your family is affected by one of these conditions, your GP can explain whether you have a risk of developing a brain tumour. They may refer you to a genetics clinic. Genetic Alliance UK also offers information and support about rare inherited conditions.

A weakened immune system

When a cancer called lymphoma starts in the brain or spinal cord, it is called primary central nervous system lymphoma. There is a higher risk of this type of lymphoma in people with a weakened immune system, for example because of:

  • HIV infection
  • long-term treatment with drugs that lower the immune system (immunosuppressants).

Other unproven causes

Hurting your head or brain in an accident has not been shown to cause brain tumours.

Mobile phones, power lines and viruses have all been suggested as possible causes of brain tumours. But research has not found any clear evidence to link any of these things to brain tumours.