Risk factors

A risk factor is anything that increases a person’s chance of getting a certain condition or disease.

In adults, lifestyle and environmental factors (such as smoking or exposure to certain chemicals) can be significant risk factors for developing certain types of cancer. Researchers know about some risk factors that increase the chance of developing cancer in children. But, for most children with cancer, the underlying cause is unknown.

What we do know is that if a child develops cancer, it’s not because of something they, or their parents did to cause it. No one is to blame if a child develops cancer.

Even if your child has a risk factor, it does not mean they will develop cancer. Many children with a risk factor will never develop cancer, while others with cancer may have had no known risk factors. Even if a child with a risk factor develops cancer, it is usually hard to know how much that risk factor contributed to the cancer.

Researchers don’t completely understand what causes leukaemia. But there are some things linked to a higher chance of developing the condition.


Family history

Children who have a brother or sister with leukaemia have a slightly higher chance of developing leukaemia. This is especially true if a child has a twin.

Genetic conditions

Some changes in a child’s chromosomes or genes can lead to leukaemia. Certain genetic conditions can also increase a child’s risk of developing leukaemia, including:

  • Down syndrome
  • Klinefelter syndrome
  • Shwachman syndrome
  • Bloom syndrome
  • Li–Fraumeni syndrome
  • Noonan syndrome
  • Wiscott–Aldrich syndrome
  • neurofibromatosis type
  • Fanconi anaemia
  • ataxia-telangiectasia.

If your child has one of these genetic conditions, they will need specific care. Your health care team will talk to you about which ongoing tests your child will need.

Cancers in children that are linked to genetic conditions may also affect the risk for other family members. You can ask your child’s treatment team if you or your family should get genetic counselling.

For more information about genetic conditions, see the children’s cancer glossary or the Centre for Genetics Education.

Exposure to radiation

High doses of radiation will increase a child’s risk of getting leukaemia. This includes children who were X-rayed before they were born.

Children who have previously had radiation therapy (radiotherapy) to treat cancer also have a higher chance of developing leukaemia.

Previous chemotherapy

Children who have been treated with chemotherapy have a higher risk of getting leukaemia.