Risk factors for childhood brain and spinal cord cancer
A risk factor is something that increases the risk of developing cancer. It could be a behaviour, substance or condition. Most cancers are the result of many risk factors. But sometimes childhood brain and spinal cord cancer develops in children who don’t have any of the risk factors described below.
Most cases of childhood brain and spinal cord cancer happen during the first 10 years of life. Boys are more likely than girls to develop a medulloblastoma or ependymoma. Boys and girls have similar incidence rates for all other tumour types.
The following are risk factors for childhood brain and spinal cord cancer. Most of the risk factors are not modifiable. This means that you can’t change them. Until we learn more about these risk factors, there are no specific ways you can reduce your risk.
Risk factors are generally listed in order from most to least important. But in most cases, it is impossible to rank them with absolute certainty.
|Known risk factors||Possible risk factors|
Known risk factors
There is convincing evidence that the following factors increase a child’s risk for brain and spinal cord cancer.
An inherited, or genetic, condition is passed from parents to their children through genes. Children with the following inherited conditions have a higher risk of developing brain and spinal cord tumours.
Neurofibromatosis affects the nerves, muscles, bones and skin. Both neurofibromatosis type 1 (von Recklinghausen disease, or NF1) and neurofibromatosis type 2 (acoustic neuroma, or NF2) increase the risk for childhood brain and spinal cord cancer. But these cancers occur more often in children with NF1. Some research shows that brain and spinal tumours caused by NF2 tend to be slow-growing and non-cancerous.
Von Hippel-Lindau (VHL) syndrome is rare. It makes blood vessels grow into knots called angiomas. These knots occur in parts of the body that are rich in blood vessels, such as the brain, spinal cord and adrenal glands.
Li-Fraumeni syndrome increases the risk of developing a number of different types of cancer, including brain tumours.
Tuberous sclerosis is also called Bourneville’s disease. It causes non-cancerous tumours to develop in the brain and spinal cord, skin, heart or kidneys.
Turcot syndrome causes multiple growths, called polyps, in the colon. It also causes tumours of the brain and spinal cord.
Basal cell nevus syndrome is also called Gorlin syndrome or nevoid basal cell carcinoma syndrome. It causes problems with several organs and increases the risk of developing different types of tumours, including brain and spinal cord tumours.
Cowden syndrome causes many non-cancerous growths, called hamartomas, to develop in the skin, breast, thyroid, colon, small intestine and mouth.
Rubinstein-Taybi syndrome (RSTS) is also called broad thumb-hallux syndrome. People with this syndrome have unique facial features, wide and crooked thumbs and big toes, short stature and intellectual disability. RSTS increases the risk of developing different types of tumours, including brain tumours.
Researchers have shown that radiation to the head and neck increases the risk of developing childhood brain tumours. Radiation to the head may be used to treat cancer or tinea capitis (a fungal infection of the scalp). Children who received radiation to the head for these conditions have a higher risk of developing a brain tumour when they are adults. It is important to remember that the higher risk of developing a brain tumour from radiation therapy is small compared to the risk of not treating the original cancer.
Children can also be exposed to radiation from CT scans and x-rays, although the dose of radiation from these imaging tests is lower today than it was in the past. Research suggests that CT scans are linked with a higher risk of brain tumours. There is some evidence that children exposed to x-ray while they are in the womb have a higher risk of developing primitive neuroectodermal tumours (PNET) but not other types of childhood brain and spinal cord tumours. Other types of x-rays, such as dental x-rays, don’t appear to increase the risk of childhood brain and spinal cord tumours.
It is important to remember that CT scans and x-rays help diagnose illness and make sure you or your children have the right treatment. Doctors will order these tests when they think you or your children need them. They will make sure that exposure to medical radiation is as low as possible.
Having any type of birth defect, especially one that affects the nervous system, is a possible risk factor for childhood brain and spinal cord cancer. This means that it has been linked with childhood brain and spinal cord cancer, but there is not enough evidence to show that it is a known risk factor.
Research suggests that children born with a birth defect in the nervous system have the highest risk of developing childhood brain and spinal cord cancer.
Unknown risk factors
It isn’t known whether or not the following factors are linked with childhood brain and spinal cord cancer. It may be that researchers can’t show a definite link or that studies have had different results. Further study is needed to see if the following are risk factors for childhood brain and spinal cord cancer:
- non-ionizing radiation sources such as cellphones and electromagnetic fields (EMFs)
- family history of a brain or spinal cord tumour
- infections during pregnancy
- birth weight more than 4 kg (about 9 pounds)
- having parents who are older when the child is born
- mother’s intake of processed meats (such as hot dogs or bacon) during pregnancy
- exposure to pesticides
- having parents with occupational exposures to farming, pesticides, electronic parts, textiles, engine exhausts, petroleum products and paint
- having parents who smoked during pregnancy
Questions to ask your healthcare team
Ask your child’s healthcare team questions about risks.
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What’s the lifetime risk of getting cancer?
The latest Canadian Cancer Statistics report shows about half of Canadians are expected to be diagnosed with cancer in their lifetime.