This page is part of the PanCare PLAIN summaries about late effects and recommendations for long-term follow-up care for survivors of childhood, adolescent, and young adult cancer. Click here, for more information on the PLAIN summaries.

Subsequent cancer: thyroid cancer

The thyroid is a gland at the front of the neck. The most important function of the thyroid is to produce hormones. Thyroid hormones control every cell and all the organs in the body. In children, thyroid hormones are important for the growth and development of the brain.

Sometimes, some cells in the thyroid become abnormal and cause a nodule (small lump) to grow. Most nodules are benign (non-malignant) but they may occasionally become malignant (thyroid cancer). Thyroid cancer is almost always curable.

Only a very few people who have had cancer before develop thyroid cancer.

Due to treatment of the first cancer, survivors sometimes have a higher risk of thyroid cancer.

Am I at higher risk of thyroid cancer?

Anyone, including people who have never had cancer treatment, may develop thyroid cancer. However, there are some cancer treatments that may increase the risk of having thyroid cancer as a subsequent cancer later in life.

The following treatments can increase the risk of thyroid cancer:

  • Radiotherapy to the neck or an area including the thyroid
  • Therapeutic radioactive iodine (131I-MIBG), a type of internal radiotherapy used to treat neuroblastoma

You can find out if you have received any of these treatments by looking at your treatment summary. If you do not have a treatment summary or if you have any questions, do contact your treating hospital.

If you develop thyroid cancer, it does not always mean that this is caused by treatment for your first cancer. Thyroid cancer may have other causes. If cancer at an unusually young age is common in your family, this may also increase your risk of having thyroid cancer.

What are the symptoms and signs of thyroid cancer?

There are symptoms and signs that can tell you if you might have thyroid cancer. You might not have these symptoms and signs at the moment, but it is important to be aware of them in case they may develop in the future.

The most important sign of thyroid cancer is:

  • a lump or swelling in the front of the neck that:
    • Is usually painless
    • Feels firm
    • Gets bigger over time

Other rare symptoms and signs of thyroid cancer are:

  • Difficulty swallowing
  • Swollen glands in the neck
  • Unexplained hoarseness / change of voice
  • Difficulty breathing

Usually thyroid nodules are harmless and very often these symptoms have another cause. However, early diagnosis and treatment of thyroid cancer is very important. If you experience any of these symptoms or signs, please contact your general practitioner or follow-up care specialist soon.

I am at higher risk of thyroid cancer. What tests should I have and when?

Whenever you visit your follow-up care specialist, they may:

  • Do a physical exam of the neck.

If you are at higher risk of thyroid cancer, you and your follow-up care specialist will discuss and jointly decide if you want follow-up care and if yes, what the preferred follow-up care for you is (this is called shared-decision making). This may be:

An ultrasound of the thyroid every 3-5 years, starting 5 years after radiotherapy ended. OR Having a physical exam of the neck done more often (every 1-2 years), starting 5 years after radiotherapy ended.

Having these tests done (more often) has its advantages and disadvantages, for example:

(More frequent) testing for thyroid cancer

Advantages Disadvantages
  • If you develop thyroid cancer, more testing may help to catch the disease in an early stage. This could help treat the cancer more easily, with less heavy treatments. However, it is important to note that thyroid cancer is almost always curable, no matter what stage it is in. 
  • If you do not develop thyroid cancer, having tests done more often could make you feel reassured that you do not have thyroid cancer.
  • More testing for thyroid cancer can cause anxiety when you are waiting for test results. 
  • Tests for thyroid cancer are sometimes difficult to interpret. This means that sometimes additional testing is needed, which can lead to additional anxiety and stress.

What happens if I (might) have thyroid cancer?

If you (might) have thyroid cancer, your general practitioner or follow-up care specialist will refer you to an oncology team. This team may include, but is not limited to:

  • Thyroid surgeon (surgeon specialised in the thyroid)
  • Medical oncologist (physician specialised in cancer)
  • Radiation oncologist (physician specialised in treating cancer with radiotherapy)
  • Endocrinologist (physician specialised in hormones and metabolism)

The specialist may discuss different treatment options with you.

What else can I do?

Knowing that you may be at increased risk of subsequent cancer can be difficult. Talking to friends and family can be helpful as well as specialist counselling and/or contact with support groups, such as patient organisations. For more information on taking care of your mental health, please read: Mental health problems.

Although we are not sure of its effect on your risk of thyroid cancer, it is still important to live a healthy lifestyle. Taking care of your mental health may be beneficial; even small changes to your lifestyle can have a positive impact on both your physical and mental health. For more information on taking up a healthier lifestyle, please read: Health promotion.

It is important that you are aware of the possibility of developing thyroid cancer and that you know the symptoms and signs. If you have any further questions or the information in this brochure concerns you, please contact your general practitioner or follow-up care specialist.

Where can I find more information?

You may find more information about thyroid cancer online. However, it is important to be aware that this information is not always up to date or accurate.

On this website, you can also find more information related to this topic:

Please note

This PLAIN summary is based on the PanCareFollowUp guideline about “Subsequent thyroid cancer” [1], which is itself based on the corresponding IGHG* guideline [2].

While the PanCare PLAIN information group strives to provide accurate and complete information that is up-to-date as of the date of publication, you can check with your general practitioner or follow-up care specialist if this summary reflects the most up-to-date information available and whether it is relevant for you.

Please do not rely solely on this information. It is best to also seek the advice of a qualified medical practitioner if you have questions regarding a specific medical condition, disease, diagnosis or symptom.

No warranty or representation, expressed or implied, is made concerning the accuracy, reliability, completeness, relevance, or timeliness of this information. PanCare has produced the English version and PanCare is not responsible for the translated versions of this summary.

The PanCare materials are free to use for anyone aiming to inform about late effects and long-term survivorship care. However, no financial advantage may be achieved. All communication should reference PanCare and link to the PanCare website.

*International Guideline Harmonization Group for Late Effects of Childhood Cancer

[1] van Kalsbeek, R. et al. (2021) European PANCAREFOLLOWUP recommendations for surveillance of late effects of childhood, adolescent, and Young Adult Cancer, European journal of cancer. Available at:

[2] Clement, S.C. et al. (2017) Balancing the benefits and harms of thyroid cancer surveillance in survivors of Childhood, adolescent and young adult cancer: Recommendations from the international Late Effects of Childhood Cancer Guideline Harmonization Group in collaboration with the PanCareSurFup Consortium. Available at: