Skip to Main Content

Welcome to

Together is a new resource for anyone affected by pediatric cancer - patients and their parents, family members, and friends.

Learn More

Second Cancers

What are second cancers?

Sometimes childhood cancer treatment can cause a second cancer to happen later. This is rare.

A second cancer is a different cancer that occurs at least 2 months after cancer treatment ends.

We all have a risk of developing cancer as we age. But childhood cancer survivors have a higher risk of cancer than others. Some risks can be lowered. Some cannot.

By knowing your risk, you can work with your health care provider to develop a plan. Factors that increase the risk of a second cancer include:

  • Younger age at diagnosis (for some cancers)
  • Certain chemotherapy and radiation
  • Your genes and family history
  • Lifestyle habits
  • Getting older

Treatments that increase the risk of second cancers

Certain chemotherapy drugs and radiation treatments may cause cancer later in life. But this risk has decreased over the years. Doctors have learned how to adjust treatments to lessen the chance of second cancers. These advances include lower doses of chemotherapy and radiation. In some cases, radiation is no longer used.


Some chemotherapy may cause acute myeloid leukemia (AML). But this is rare with new treatment approaches.  It most often appears less than 10 years after treatment. 

You may have a higher risk if you had:

Radiation therapy

Radiation therapy increases the risk of cancer of the skin, soft tissues, and bones. Most second cancers occur in or near the area that received radiation. These cancers most often appear more than 10 years after treatment.

The risk is highest if you had radiation at a young age and at a high dose. The most common sites include:

  • Skin
  • Breast
  • Central nervous system (brain and spinal cord)
  • Thyroid gland
  • Bones
A small group women stand with their fists up as they participate in a boxing class.

Regular physical activity may help lower your risk of having a second cancer.

Other risk factors for second cancers

Inherited risk

Some people have a higher chance of having cancer because they are born with a genetic condition. This is called cancer predisposition

Sometimes people inherit the condition from one or both parents. In other cases, they are the first person in the family to get cancer. 

Studies show about 10% of childhood cancers are inherited. 

Lifestyle habits

A healthy lifestyle is important. It can help prevent obesity. Obesity can be a risk factor for cancer. Good health habits may also lower the risk of some types of adult cancers.

What survivors can do

Questions to ask about second cancers

  • What is my risk of having a second cancer?
  • Does the treatment I received put me at higher risk for a second cancer?
  • Am I at risk of other complications from childhood cancer treatment?
  • What can I do to lessen my risk of having a second cancer?
  • What can I do to lower my anxiety about having a second cancer?


Key points about second cancers

  • Second cancers in childhood cancer survivors are rare. But they happen more in childhood cancer survivors than others.
  • A second cancer is a different cancer that occurs at least 2 months after cancer treatment ends.
  • Some risks can be lowered. Others cannot.
  • Risk factors include young age at time of treatment, chemotherapy drugs, radiation, inherited conditions, some lifestyle habits, and getting older.
  • Work with your health care provider on a plan to lower your risk of developing a second cancer. 

Related content

Reviewed: January 2023