Most malignant brain tumours are caused by a cancer that started somewhere else in the body and spread to the brain through the bloodstream.

The cause of primary malignant brain tumours (cancerous tumours that start in the brain) is not fully understood.

Underlying disease

Some genetic conditions can increase your risk of a primary malignant brain tumour. These conditions include:

• neurofibromatosis 
• tuberous sclerosis 
• Turcot syndrome
• Li-Fraumeni cancer syndrome
• von Hippel-Lindau syndrome
• Gorlin syndrome

These conditions tend to cause malignant gliomas (tumours of the glial tissue, which binds nerve cells and fibres together) that appear in childhood or early adulthood, whereas most gliomas start later in adulthood.

Radiotherapy to the brain increases your risk of a brain tumour, although this is still uncommon.

It is also thought that you are at an increased risk if you have a family history of brain tumours and are exposed to chemicals (such as formaldehyde).

There have been reports in the media about a possible connection between brain tumours and the radiofrequency (RF) energy emitted by mobile phones. RF energy produces heat, which can increase body temperature and damage tissue exposed to it.

It is thought that the amount of RF energy people are exposed to by mobile phones is too low to produce significant tissue heating or an increase in body temperature.

However, research is under way to establish whether RF energy has any effects on our health in the long term. No definitive conclusions have yet been reached.

Read mobile phone safety for more information.