Thyroid and Parathyroid Cancer | Cancer


Thyroid Cancer

Thyroid cancer is an endocrine system cancer that affects your thyroid gland. Our expert cancer team offers advanced treatments for thyroid and parathyroid cancers.

Medically reviewed by Michael Campbell, M.D. on Nov. 20, 2023.

Female provider examining a male patient's thyroid gland

Expert Team Protecting Your Health

UC Davis Comprehensive Cancer Center provides the latest care for all types of thyroid cancer. A team of cancer experts, as well as endocrinologists and endocrine surgeons, work together to treat thyroid cancer and protect your health.

Our thyroid cancer team specializes in minimally invasive thyroidectomy surgery that protects your vocal cords and parathyroids. We are a high-volume endocrine oncology center that performs both straight forward and very complex thyroid surgery. You also benefit from a full range of nonsurgical treatments.


What Is Thyroid Cancer?

Thyroid cancer is a type of endocrine system cancer that affects your thyroid gland. This small, butterfly-shaped gland sits at the base of your neck. It makes and releases hormones into your blood. These chemicals send messages that keep your organs, muscles and tissues working as they should.

Thyroid gland hormones help control:

  • Blood pressure
  • Body temperature
  • Heart rate
  • Metabolic rate (how your body turns food into energy and uses that energy)

The different types of thyroid cancer depend on the type of cancer cell. They include:

  • Papillary thyroid cancers account for 8 in 10 diagnoses. It usually grows slowly and responds well to treatment, making it highly curable.
  • Follicular thyroid cancer and Hurthle cell cancers makes up 1 in 10 thyroid cancer diagnoses. It is more likely to spread to the bones and lungs making it harder to treat.
  • Medullary thyroid cancer (MTC) develops in C cells. These cells make a hormone (calcitonin) that helps controls how your body uses calcium. MTC sometimes runs in families.
  • Anaplastic thyroid cancer is an aggressive cancer that spreads, making it difficult to treat. This rare type accounts for about 2% of all thyroid cancer diagnoses.
  • Parathyroid cancer forms in one or more of the four tiny parathyroid glands at the back of the thyroid. These glands control your body’s calcium levels. Parathyroid cancer is extremely rare.

Thyroid Cancer Symptoms

During its early stage, thyroid cancer may not cause symptoms until the tumor gets bigger.

Common Symptoms

Common signs of thyroid cancer include:

Emergency Symptoms

Thyroid cancer can spread (metastasize) to other parts of your body. You should see your provider if you have these symptoms:

  • Extreme fatigue
  • Loss of appetite
  • Nausea and vomiting
  • Unexplained weight loss

Causes and Risk Factors of Thyroid Cancer

Medical experts don’t always know why certain cells in the thyroid gland become cancerous. Some people have gene changes (mutations) in their family that make them more prone to thyroid cancer. A familial gene change causes up to 5% of papillary thyroid cancers and up to 30% of medullary thyroid cancer.

Anyone can develop thyroid cancer, but the following factors increase your risk:

Age, Biological Sex and Race

Women are almost three times more likely to develop thyroid cancer, with white women most at risk. Most women are in their early 50s at the time of diagnosis.


Diets high in iodine (a mineral) may increase the risk of papillary thyroid cancer. A low-iodine diet may contribute to follicular thyroid cancer.

Excess Weight

People who have obesity or excess weight have an increased risk of thyroid cancer.

Family History

Having a family member with thyroid cancer may increase your chance of having the same cancer. Certain familial endocrine and hormonal disorders, such as multiple endocrine neoplasia (MEN), also increase thyroid cancer risk.

Thyroid Disorders

Certain thyroid disorders, such as an enlarged thyroid (goiter), may contribute to thyroid cancer.

Treatment Side Effects

Radiation therapy for head and neck cancers may pose a risk, especially if the treatment took place during childhood.  


Diagnosis and Testing of Thyroid Cancer

To make a thyroid cancer diagnosis, your healthcare provider will review your medical history and perform a physical exam. During the exam, they’ll check for swelling or lumps in your neck.

You may have one or more of these diagnostic tests:

  • Blood tests: A blood test can detect hormone changes that may suggest a problem with your thyroid gland. Blood tests can’t detect thyroid cancer, but they can help rule out other conditions.
  • Imaging tests: An ultrasound can determine if a thyroid nodule is solid (more likely to be cancerous) or filled with fluid. You may also get a CT scan or MRI to check for thyroid nodules.
  • Laryngoscopy: Your provider uses a lighted scope device to see if a thyroid nodule is pressing on the vocal cords in your voice box (larynx).
  • Radioactive iodine (radioiodine) scan: You receive an injection or take a pill with safe, low levels of radioiodine. Your health care provider uses a special camera to measure inside your body to determine if it’s cancer.
  • Thyroid biopsy (FNA): Your provider performs a fine-needle biopsy to remove a small sample of cells from the thyroid nodule or lymph nodes. Experts at our Department of Pathology and Laboratory Medicine check for cancer cells and determine the cancer type. Biopsies also take place after surgical removal of a diseased thyroid gland.

Thyroid and Parathyroid Cancer Treatments

Surgery is the cornerstone of treatment for thyroid cancer and often cures the disease. At the UC Davis Comprehensive Cancer Center, we specialize in minimally invasive thyroid cancer surgery. Surgery takes place through small incisions, so you heal faster with minimal scarring and pain.

Parathyroidectomy is the main treatment of parathyroid cancer. Sometimes a portion of the thyroid cancer needs to be removed with the parathyroid cancer.

We treat thyroid and parathyroid cancer while protecting your speech. During surgery, we use advanced technology to continually monitor and preserve the recurrent laryngeal nerve that controls your voice box.

After thyroid cancer treatments, you’ll need thyroid hormone replacement therapy. You take this medicine daily. 

Thyroid Surgery

Depending on the cancer stage and location, your provider may remove part of the thyroid gland (thyroid lobectomy) or the entire gland (total thyroidectomy). They may also remove nearby lymph nodes.

Radioactive Iodine (Radioiodine) Therapy

Our specialized endocrinologists and nuclear medicine team can coordinate your radioiodine therapy via an injection or oral medication. You receive radioiodine in higher (but still safe) amounts than the diagnostic test. Radioiodine destroys any small amounts of remaining thyroid tissue or cancer cells without harming the rest of your body.

Radiation Therapy

External beam radiation therapy uses a machine to deliver high-powered X-ray beams to the tumor. The radiation kills cancer cells.

Targeted Therapy

Kinase inhibitors are a type of targeted therapy for certain types of thyroid cancer. The drugs target the gene changes that cause cancer cells to grow.


Preventing Thyroid Cancer

Thyroid cancer usually develops for no known reason, which means you can’t prevent it. The exception is if you have an inherited condition that increases your cancer risk.

Preventive (Prophylactic) Surgery

Preventive (prophylactic) surgery removes the thyroid gland before cancer develops. You may opt for this procedure if gene tests show you have a RET mutation or at risk for medullary thyroid cancer.

"What Is Thyroid Cancer?" American Cancer Society,

"Key Statistics for Thyroid Cancer" American Cancer Society,

Who does it affect?

43K+New cases of thyroid cancer each year

Annual deaths

2K+Americans die from thyroid cancer each year

Source: American Cancer Society: Key Statistics for Thyroid Cancer

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