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Thyroid and parathyroid cancer

Overview of thyroid and parathyroid cancer

Thyroid cancer results from having malignant cells in your thyroid gland. The thyroid is a butterfly-shaped gland in your neck responsible for producing the thyroid hormones, which control metabolism, growth, and other important processes in your body.

Compared to other cancers, thyroid cancer is not common. On average, 45,000 Americans find out they have it each year.

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Early thyroid cancer generally doesn’t cause observable symptoms. When signs do occur, the most common is a lump or swelling in the neck. Lumps may be more obvious when you shave or put on makeup.

Other symptoms may appear in more advanced stages:

  • Aching in the front of the neck that may extend to the ears
  • Trouble swallowing or breathing
  • Constant cough
  • Hoarseness or other voice changes that persist
  • Feeling a sensation of pressure on your throat when sleeping or lying down (this is uncommon unless there is a large tumor)

If you notice any of these, your doctor can help determine whether they are cause for concern. While many of these symptoms do not indicate a serious condition, it’s important to diagnose them as soon as possible.


Like other types of cancer, thyroid cancer is caused by cell mutations. This abnormal cell growth can then form tumors or spread elsewhere in the body. Experts still don’t fully understand why cancer occurs in some people and not others.

However, some factors are known to make cell DNA damage or mutations more likely, such as smoking, being overweight, exposure to radiation, inheriting specific genes that are linked to cancer, and having a previous diagnosis of cancer in the thyroid or elsewhere in the body.


There are five main types of thyroid cancer:

  • Papillary carcinoma is slow-growing cancer that develops in a single lobe of the thyroid gland. Representing 80 percent of known cases, this is the most common form of thyroid cancer. Papillary carcinoma is highly curable.
  • Follicular carcinoma starts in the cells that make thyroid hormone. About 1 in 10 people get this form of thyroid cancer. It is more commonly found in countries with low-iodine diets.
  • Hurthle cell carcinoma is a variation of follicular carcinoma, but it is harder to detect and treat. About 3 percent of thyroid cancers are this type.
  • Medullary thyroid carcinoma grows in cells that make the hormone calcitonin. This form makes up about 4 percent of thyroid cancers and is more challenging to treat.
  • Anaplastic carcinoma occurs when papillary or follicular cancers mutate into a very aggressive form. It spreads rapidly and is challenging to treat. It is also rare, affecting less than 2 percent of people with thyroid cancer.

Risk factors

Certain risk factors may increase the likelihood of developing thyroid cancer:

  • Family history of thyroid cancer or goiter (an enlarged thyroid).
  • Gender: Women are three times more likely than men to develop thyroid cancer.
  • Genetics: Some thyroid cancers are related to genetic conditions or mutations in genes.
  • Age: Most thyroid cancers occur in people younger than 55.
  • Exposure to high amounts of radiation: This could be due to previous cancer treatments, especially during childhood.
  • Diet low in iodine: This is usually not a problem in the United States.


Unlike some cancers, thyroid cancer does not have many predictable risk factors. It is therefore not always possible to prevent thyroid cancer.

If you do have a history of exposure to high levels of radiation, such as from childhood treatment for head or neck cancer, your doctor may suggest more regular screenings.

Likewise, if you have a family history of thyroid cancer or you’ve tested positive for the genes associated with familial medullary thyroid cancer (MTC), your doctor may suggest the preventive removal of your thyroid gland.

For those without these risks, you can stay healthy by attending regular physical checkups and speaking with your doctor about any concerns.

The information contained in this article is meant for educational purposes only and should not replace advice from your healthcare provider.