Thyroid Issues After Childhood Cancer Treatment

What is my thyroid gland?

Your thyroid is a gland in your neck. It makes hormones that are important for controlling your metabolism, growth, and development. The pituitary gland in your brain controls the thyroid's production of these hormones. Thyroid problems can include hypothyroidism (underactive thyroid), hyperthyroidism (overactive thyroid), and thyroid nodules/tumors.

Am I at risk for thyroid problems?

If you have had radiation that included your brain, thyroid gland, or came close to your thyroid gland (head & neck, upper spine, and upper chest) you are at risk for thyroid problems. Survivors treated with radioiodine therapy (I-131) or MIBG (meta-iodobenzylguanidine) therapy are also at risk.

When can the problems happen?

The risk of thyroid problems continues for your whole life. Hypo- and hyper-thyroidism most often happen between 2 and 5 years after treatment. Thyroid nodules often develop 10 years or more after treatment. The risk of thyroid issues increases with the amount of radiation received to the area. Higher doses of radiation mean the risk is higher.

When should I call my provider?

Hypothyroidism

Symptoms of hypothyroidism (the most common complication) are a result of the thyroid not making enough of the hormones. These include:

• Fatigue.
• Weight gain.
• Constipation.
• Hoarse voice.
• Dry skin and brittle hair.
• Always feeling cold.
• Mood changes or feeling sad or depressed.

Hyperthyroidism

Symptoms of hyperthyroidism are a result of the thyroid making too much of the hormones. These include:

• Feeling anxious or tense.
• Trouble sleeping.
• Fast heart rate.
• Sweating or feeling hot all the time.
• Diarrhea.
• Weight loss.
• Shaky hands.

Thyroid Nodules

Thyroid nodules can appear as a painless bump or lump in your neck. Depending on the location, you may be able to feel it, or it can press on your throat causing symptoms like trouble swallowing or a change in your voice. Many thyroid nodules will have no noticeable symptoms.

How do I monitor my health and follow-up care?

If you are a childhood cancer survivor, you should know your risk and monitor your health. Some ways to monitor your health are:

• If you have had radiation to the brain or neck, you should have a physical exam by your provider every year.
• Inform your provider about any symptoms that could be caused by a thyroid issue (as listed above).
• You should have blood tests to check your thyroid function. This includes a TSH (thyroid-stimulating hormone) and T4 level.
• Your provider should examine your thyroid gland. This is done by feeling your thyroid gland. If they feel a lump, you will likely have a thyroid ultrasound to help determine if the nodule/lump is benign (not cancerous) or concerning (possibly cancerous).
• Children and teens should have their growth evaluated each year as it can be affected by thyroid issues.
• Women who wish to become pregnant should have their thyroid blood levels checked before pregnancy. Babies born to mothers with thyroid issues are more likely to have developmental problems.

How can I learn more about my risk?

• Going to a cancer survivorship clinic can be helpful to learn about your own risk and ways to reduce your risk. Find a clinic on our list or call local cancer centers to see if they have one for childhood cancer survivors.
• Visit the Children’s Oncology Group website to learn more about risks and recommendations.
• Talk with your care team about your plan for follow-up care.