CCS adapting to COVID-19 realities to support Canadians during and after the pandemic
Risk factors for Wilms tumour
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 Wilms tumour develops in children who don’t have any of the risk factors described below.
Most Wilms tumours are diagnosed in children younger than 5 years of age. Wilms tumours develop slightly more often in children of African ancestry and less often in children of Asian ancestry. They develop slightly more often in girls than boys.
The following are risk factors for Wilms tumour. All 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 the risk.
Children with certain genetic conditions have a higher than average risk for Wilms tumour. Talk to your doctor about your child’s risk. If your child has a genetic condition that increases the risk of Wilms tumour, your child may need to visit the doctor more often to check for Wilms tumour. Your doctor will recommend what tests your child should have and how often to have them.
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.
There is convincing evidence that the following factors increase your risk for Wilms tumour.
WAGR syndrome is a rare genetic condition. It is caused by loss or inactivation of a tumour suppressor gene. Tumour suppressor genes usually control cell growth and stop tumours from growing. When these genes aren’t present or don’t work properly, they no longer control cell growth and tumours may form.
WAGR stands for the 4 conditions that may be present in WAGR syndrome:
- Wilms tumour
- aniridia, which is when the coloured part of the eye (the iris) doesn’t form completely
- genitourinary anomalies, which means the reproductive and urinary systems don’t form normally
- intellectual disability
Most people who have WAGR syndrome have 2 or more of these conditions. Children with WAGR syndrome have about a 30% chance of developing Wilms tumour.
Denys-Drash syndrome is a genetic condition that causes kidney disease within the first few months of life. It also affects the sex organs so they don’t form properly.
About 90% of children with Denys-Drash syndrome develop Wilms tumour in one or both kidneys. It is usually diagnosed around 2 years of age.
Perlman syndrome is a very rare genetic condition. It is very similar to Beckwith-Wiedemann syndrome. During pregnancy, there is too much fluid in the uterus. As a result, the baby may be born larger and heavier than normal, with abnormal facial features.
Babies and children with Perlman syndrome have about a 33% risk of developing Wilms tumour.
Simpson-Golabi-Behmel syndrome is a genetic condition found mostly in boys. It affects many parts of the body. Babies with Simpson-Golabi-Behmel syndrome are much larger than normal at birth, and they grow and gain weight at an unusual rate.
About 10% of children with Simpson-Golabi-Behmel syndrome will develop non-cancerous or cancerous tumours during childhood. The most common of these cancers is Wilms tumour.
Frasier syndrome is a very rare genetic condition. In boys, Frasier syndrome affects both kidneys and affects the genitals so they don’t form properly. In girls, it usually only affects the kidneys.
Children with Frasier syndrome have about an 8% risk of developing Wilms tumour.
Beckwith-Wiedemann syndrome is an inherited condition that affects how different parts of the body grow. Signs include large body size, large tongue, large organs, a defect in the abdominal wall and low blood sugar in newborns.
Children with Beckwith-Wiedemann syndrome have about a 5% risk of developing Wilms tumour.
Bloom syndrome is an inherited condition caused by mutations in a certain chromosome. Signs include shorter than average height, a high-pitched voice and a characteristic facial appearance.
Children with Bloom syndrome have about a 3% risk of developing certain cancers, including Wilms tumour.
Li-Fraumeni syndrome is an inherited condition that is associated with a higher risk for certain types of cancers, including Wilms tumour.
The following birth defects are linked with an increased risk for Wilms tumour.
Aniridia is a rare birth defect in which the coloured part of the eye (the iris) doesn’t form completely. The iris controls the amount of light entering the eye. Aniridia can cause blindness.
Hemihypertrophy is a birth defect that causes part or one side of the body to grow larger than the other.
Undescended testicles, or cryptorchidism, is a condition in which one or both testicles do not move (descend) from the abdomen into the scrotum. It is usually found shortly after birth.
Hypospadias is a birth defect in boys. It occurs when the urinary (urethral) opening is on the underside of the penis rather than at the tip.
A small number of Wilms tumours develop in children who have family members with the disease. About 1% to 2% of children diagnosed with Wilms tumour have a family history of the disease.
Possible risk factors
A high birth weight and Sotos syndrome have both been linked with Wilms tumour, but there is not enough evidence to show for sure that they are risk factors. Sotos syndrome is a rare genetic condition that causes excessive physical growth during the first years of life. More research is needed to clarify the role of these factors for Wilms tumour.
Questions to ask your healthcare team
Ask your child’s healthcare team questions about risks.
Passed from parent to child through information contained in genes.
Also referred to as hereditary.
Together we can reduce the burden of cancer
Last year, we only had the resources available to fund 40% of high-priority research projects. Imagine the impact we could have if we were able to fund 100%.