Causes, Risk Factors, and Prevention of Cancer in Children

The exact cause of cancer in most children is not known.

Researchers are learning how gene changes play a role, but in most cases, we don’t know what causes these changes. There aren’t many known risk factors for childhood cancer. Because of this, there are not many ways to prevent it.

Most gene changes in childhood cancer happen by chance as a child grows, sometimes very early in development. Only about 1 in 12 childhood cancers are caused by gene changes that are passed on in families.

What causes childhood cancer?

Scientists have found some risk factors for childhood cancer, but most children who develop cancer have no risk factors. A risk factor is anything that affects a person’s chance of getting a disease, such as cancer.

Researchers have found that gene changes play a role in cancer growth and development, but often we don’t know what causes them.

How normal cells become cancer cells

DNA is the chemical in our cells that makes up our genes. DNA controls how our cells function. Changes (mutations) in the DNA inside our cells can sometimes alter the way some genes work. These changes can cause cells to grow out of control and become cancer.

Some genes control when our cells grow, divide into new cells, and die:

• Genes that help cells grow, divide, or stay alive can sometimes lose the ability to turn off. They can become oncogenes.
• Tumor suppressor genes tell cells to stop dividing or cause cells to die at the right time.
• DNA repair genes find and fix damage to the DNA that might happen during cell growth or from the environment.

Acquired versus inherited gene changes in cancer

Cancers can be caused by DNA changes. The changes can create oncogenes, turn off tumor suppressor genes, or damage DNA repair genes.

These gene changes can happen before birth. Or they can be inherited from a parent. However, most gene changes that cause childhood cancers happen by chance in early life. These acquired or de novo gene changes can result from environmental exposures, such as radiation. But most of them occur by chance.

To learn more, see Gene Changes and Cancer.

What increases the chance of a child getting cancer?

A risk factor is anything that increases the chances of getting a disease, such as cancer. Different cancers have different risk factors. Most childhood cancers are thought to be caused by gene changes that happen by chance.

Most of the common risk factors for adult cancers take many years to increase cancer risk. These include risk factors like using tobacco, alcohol, excess weight, poor diet, and not being physically active. Because of this, scientists don’t believe these risk factors are a cause of childhood cancer.

There are two main types of risk factors for cancer: genetic and environmental.

Can childhood cancers be prevented?

Limiting exposure to radiation, certain chemicals, and infections may lower the risk of some childhood cancers. However, because the causes of most childhood cancers are not known, most childhood cancers cannot be prevented.

If a child has a known gene mutation or family cancer syndrome that increases their risk of certain cancers, doctors might suggest some cancer screening tests earlier or more often than most people. Depending on the type of mutation, the care team might suggest ways to prevent or reduce the child’s risk of developing cancer.

If your child develops cancer, there was likely nothing you or your child could have done to prevent it.

What can parents do to lower their child’s risk of cancer later in life?

Parents and caregivers have an important role in supporting their children’s long-term health. The habits you help your child develop can reduce their risk of cancer later in life. Here are some ways you can support them:

• Avoid smoking and secondhand smoke. Smoking causes 1 in 5 cancers. And it causes 1 in 3 cancer deaths. It also increases the risk of many cancers, not just lung cancer.
• Help them get to and stay at a healthy weight.  The best way to do this is to combine physical activity with healthy eating.
• Encourage young adults to avoid or limit alcohol. Any amount of alcohol increases the risk of several cancers.
• Get your child vaccinated against human papillomavirus (HPV). HPV causes almost all cervical cancers. It can also cause mouth and throat cancer. HPV vaccines can prevent more than 90% of HPV-related cancers when given at the recommended ages.
• Limit sun exposure and protect your child’s skin. Protect your child’s skin from direct sunlight, which is the main source of ultraviolet (UV) radiation. This lowers their risk of skin cancers.
• Encourage safe sex practices to prevent exposure to certain infections. Talking about sexual health is important for teens and young adults. Protecting against infections such as HPV, hepatitis B and C, and human immunodeficiency virus (HIV) can lower the risk of developing certain types of cancer.
• Talk about cancer screening tests that may be recommended as your child ages. Cancer screening tests can catch cancer early, when it is more easily treated. In some cases, screening tests  can find and remove precancerous areas before cancer develops.

Learn more about Cancer Risk and Prevention.