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.

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:

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.

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 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.