The short answer
NCI lists radiation exposure in childhood, being female, age 25 to 65, goiter, family history, and certain inherited conditions as risk factors. Having a risk factor does not mean thyroid cancer is certain.
Radiation to the head and neck in infancy or childhood, or radioactive fallout, is a listed risk factor.
Thyroid cancer is more common in women than in men.
A family history of thyroid disease or thyroid cancer raises risk.
Certain inherited conditions, such as FMTC, MEN2A and MEN2B, raise risk.
On this page
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The whole article, with every detail and caution.
The simple version
This page explains what raises the risk of thyroid cancer, for anyone worried about their own risk or a family member's. Several factors are linked to a higher risk of thyroid cancer. Some, like radiation exposure, are things that happened in the past and cannot be changed now. Others, like family history, are simply part of who you are.
Having a risk factor does not mean thyroid cancer will happen.
Known risk factors
- Age. NCI lists being between 25 and 65 years old as a risk factor.
- Sex. Being female is a risk factor. ACS says thyroid cancer is almost 3 times more common in women.
- Radiation exposure. Radiation to the head and neck as an infant or child, or exposure to radioactive fallout, is a risk factor. NCI says the cancer may occur as soon as 5 years after exposure.
- Goiter. A history of goiter (enlarged thyroid) is a listed risk factor.
- Family history. A family history of thyroid disease or thyroid cancer is a listed risk factor.
- Inherited syndromes. Familial medullary thyroid cancer (FMTC), multiple endocrine neoplasia type 2A (MEN2A), and multiple endocrine neoplasia type 2B (MEN2B) are genetic conditions NCI lists as risk factors.
- Ethnicity. NCI lists being Asian as a risk factor.
In short: age, sex, past radiation, and family history or genetics are the main known factors.
Having risk factors is not your fault
If you had radiation as a child, or if thyroid cancer runs in your family, none of that is something you chose. These factors sit largely outside anyone's control. Having a risk factor does not mean cancer will happen.
Why this matters for you
If thyroid disease or thyroid cancer runs in your family, or you have a known genetic condition, tell your doctor. Ask what that means for you and your relatives.
Signs of thyroid cancer to watch for
NCI lists these signs and symptoms:
- A lump or nodule in the neck.
- A hoarse voice.
- Trouble swallowing, or pain when swallowing.
- Trouble breathing.
Other conditions can cause the same signs. Get them checked.
When to get help sooner
- Call 911 or go to an emergency department if you suddenly cannot breathe well, or your throat feels like it is closing. Do not drive yourself.
- Call your care team the same day if a neck lump grows quickly, or swallowing becomes painful or difficult. If breathing is hard, call 911.
- Call your care team within a day or two if you notice a new lump in your neck, or hoarseness that lasts more than a couple of weeks.
Sources
Common questions
Does having an enlarged thyroid (goiter) mean I will get thyroid cancer?
A history of goiter (enlarged thyroid) is listed by NCI as a risk factor. Having one does not mean you will get thyroid cancer. Ask your doctor what your own history means.
Why are women more likely to get thyroid cancer than men?
Thyroid cancer is almost three times more common in women than in men. ACS says this cancer is almost 3 times more common in women. NCI lists being female as a risk factor.
Did past radiation treatment cause my thyroid cancer?
Radiation exposure, especially in infancy or childhood, raises the risk of thyroid cancer, sometimes appearing years later. NCI says cancer may occur as soon as 5 years after exposure. Having a risk factor does not mean cancer will happen. Ask your doctor about your own history.
What are MEN2A and MEN2B?
NCI lists familial medullary thyroid cancer (FMTC), MEN2A and MEN2B as genetic conditions that raise thyroid cancer risk. Ask your doctor whether genetic counseling makes sense for you and your family.
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Last updated: 2026-10-02Next planned review: 2027-08-03
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Cancer Explained does not originate medical claims. Every page restates guidance already published by the National Cancer Institute, the CDC, the USPSTF and the FDA, in plain language, with the source cited so you can check the original yourself. AI does the translating and organizing; automated checks test claims, citations, clarity and safety before anything publishes, and this is translation and navigation, not clinical judgment. Nothing here is personal medical advice, and no page can account for your particular situation.
Editorial status: Source checked — This page was written with AI assistance and then compared with the sources listed on it, looking for statements those sources do not back up. That check is not a sentence-by-sentence record and can miss errors. It is not a medical review, and it does not confirm the page is complete or right for your situation.
Human medical review: not completed. Pages here are not signed off by a clinician before they publish. That is not an oversight we are quietly working around: we restate published guidance and cite it, so the authority belongs to the source rather than to us, and every page names where its claims come from — you can verify us instead of trusting us. Where a volunteer clinician has reviewed a page, their name and credentials appear on it; where no name appears, no clinician has checked it. We are glad to have reviewers and are recruiting them, and we do not hold pages back waiting for one. Use this site to understand your situation and to ask better questions of the people treating you.
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