Risk factors and causes

In most cases, experts don’t know what causes a primary brain tumour. Research is going on to find out more.

Some risk factors increase the chances of developing a brain tumour. It is important to remember that having a risk factor does not mean you will get a brain tumour. In fact, most people with a tumour do not have any risk factors.


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.

We have information about brain tumours in teenagers and young adults.


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

People with some inherited genetic conditions have a higher risk of developing a brain tumour. These are rare conditions that run in families, such as:

  • 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.

A weakened immune system

This is a possible risk factor for a type of cancer called a lymphoma that starts in the brain or spinal cord. It is more likely to develop in people who have a weakened immune system. This could be because of AIDS or long-term treatment with drugs that lower the immune system (immunosuppressant drugs).

Other unproven causes

Mobile phones, power lines and viruses have all been suggested as possible causes of brain tumours. But research hasn’t found any strong evidence to link any of these to brain tumours.

Back to Diagnosing