Thyroid problems

The thyroid is a gland at the front of the neck. The most important function of the thyroid is to produce hormones. These hormones are called T3 (triiodothyronine) and T4 (thyroxine). 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. Thyroid function is regulated by another hormone produced by the brain, called TSH (thyroid-stimulating hormone).

Sometimes problems can occur with thyroid function which can cause the thyroid to decrease the production of thyroid hormones. This is called hypothyroidism. On the other hand, the thyroid may also become overactive and produce too much T3 and T4, called hyperthyroidism.

Am I at higher risk of thyroid problems?

Anyone, including people who have never had cancer treatment, may develop thyroid problems. However, there are some cancer treatments that may increase the risk of having thyroid problems later in life. The problems that can occur depend on the type of cancer treatment received.

The following treatments can lead to, or increase the risk of, thyroid problems:

  • Radiotherapy to the thyroid or an area including the thyroid may cause both hypo- and hyperthyroidism.
  • Stem cell transplantation with stem cells from a donor (allogeneic). Stem cell transplantation may cause both hypo- and hyperthyroidism.
  • Surgery, where the thyroid is removed (total thyroidectomy) always leads to hypothyroidism.
  • Therapeutic radioactive iodine (I-131 or MIBG), a type of radiotherapy, may increase the risk of hypothyroidism.

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 experience thyroid problems, it does not always mean that this is caused by your cancer treatment. Thyroid problems may have other causes, such as other drugs unrelated to cancer treatment or autoimmunity. Thyroid problems may also occur without a clear cause (idiopathic). Nearly one in ten of the general population are likely to have thyroid problems, with an increased risk in females.

What are the symptoms and signs of thyroid problems?

There are symptoms and signs that can tell you if you might have thyroid problems. 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.

These symptoms and signs may suggest that you have hypothyroidism (not enough thyroid hormones):

  • Weight gain
  • Constipation
  • Feeling cold easily
  • Hair loss or thin hair
  • Dry skin
  • Tiredness

In children and teens:

    • Poor growth and short stature (short height)
    • Difficulty concentrating or paying attention at school or work
    • Delayed puberty

These symptoms and signs may suggest that you have hyperthyroidism (too much thyroid hormones):

  • Unexplained weight loss
  • Heart palpitations (the heartbeat may be irregular or unusually fast)
  • Feeling nervous, irritable or anxious
  • Mood swings
  • Tremor – a fine trembling of the hands
  • Diarrhoea
  • Feeling (very) tired all the time
  • Sweating more than usual
  • Difficulty sleeping
  • Hair loss or thin hair
  • Swollen thyroid, lump in your neck (Goitre)
  • Eye problems, especially in adults

If you recognise any of these symptoms or signs in yourself, please contact your general practitioner or follow-up care specialist.

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

If you are at higher risk of thyroid problems, it is advised to:

  • Discuss your medical history and whether you experience(d) any symptoms and signs of thyroid problems with your general practitioner or follow-up care specialist.
  • Have a blood test done to measure levels of TSH and T4 in the blood. If you are trying to become pregnant, it is important to have a blood test beforehand. It is also important to regularly measure your TSH and T4 levels during pregnancy.

The advised interval of testing depends on your age:

  • Children (0-18 years): Once a year
  • Adults (19 years and older): Every 2-3 years

If your blood tests are abnormal, it may be necessary to confirm the diagnosis by repeating the blood test.

What happens if I have thyroid problems?

If you have thyroid problems, your general practitioner or follow-up care specialist will probably refer you to an:

  • Endocrinologist (physician who specialises in hormones and metabolism)

The endocrinologist may discuss different treatment options with you, such as hormone treatment.

What else can I do?

Knowing that you may be at increased risk of thyroid problems 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 it may not lower your risk of thyroid problems, 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 problems and that you know the symptoms and signs. If you have any further questions or if 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 problems online. However, it is important to be aware that this information is not always up to date or accurate.

Some sources of further information are:

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 “Thyroid function problems” [1], which is based on the consensus of different national guidelines.

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.

[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: