A risk factor is anything that increases a person’s chance of developing a certain condition or disease, such as cancer. 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. In children, very few risk factors have been identified that increase the chance of developing cancer. For most children with cancer, the underlying cause is unknown.
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 development of their disease.
The causes of brain and other CNS tumours are not well understood, but factors associated with a higher chance of developing brain and other CNS tumours include the following.
In rare cases, an increased chance of developing brain and other CNS tumours runs in families. This is more likely to be the case if other people in your family had brain or other CNS tumours in their childhood. When these tumours run in families, the tumour usually develops at a younger age than in children with no family history of the disease.
Knowledge of your family’s history relating to cancer may change over time.
Some types of genetic conditions can increase a child’s chance of developing brain and other CNS tumours. In these cases, specific changes in one or several genes have been identified that contribute to cancer. These conditions can run in families, or they can start in the child from a fault in their DNA.
Conditions that are associated with childhood brain and other CNS tumours include:
- neurofibromatosis type 1 (von Recklinghausen disease)
- neurofibromatosis type 2
- tuberous sclerosis
- von Hippel–Lindau syndrome
- Li–Fraumeni syndrome
- Gorlin syndrome
- Turcot syndrome.
If your child is diagnosed with one of these genetic conditions, they will need specific follow-up. The health care team will advise 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. Speak to your child’s treatment team to see whether genetic counselling is recommended for you or your family.
Exposure to radiation
Children who have had radiation exposure to the head (usually to treat other cancers such as leukaemia) have an increased chance of developing brain tumours later in life.
Diagnostic imaging tests such as computed tomography (CT) scans and X-rays expose a person to a very low dose of radiation. The potential risk to an unborn baby or child from this type of radiation exposure is not known, so doctors usually avoid these tests for pregnant women or young children unless they are essential.