The information on this page was reviewed and approved by
Maurie Markman, MD, President, Medicine & Science at CTCA.

This page was updated on September 23, 2021.

About thyroid cancer

Thyroid cancer forms in the tissues of the thyroid gland, which is located near either side of the trachea (windpipe), below the cartilage known as the Adam’s apple. Though thyroid cancer is not considered a type of head and neck cancer, it is typically treated by an otolaryngology-trained oncologist, who also treats malignancies of the mouth, nose, tonsils, sinuses, salivary glands and lymph nodes of the neck.

The thyroid gland produces several important hormones, including the thyroid hormone, which is involved in controlling body temperature, weight, energy level and heart rate. The thyroid gland also produces calcitonin, which helps the body use calcium.

The American Cancer Society estimates that 44,280 people in the United States will be diagnosed with thyroid cancer in 2021. Compared with other common types of cancer, thyroid cancer occurs more frequently in younger patients, with about 65 percent of cases occurring in people under the age of 55.

What causes thyroid cancer?

Although cancer research has not identified the exact cause of thyroid cancer, certain risk factors may increase an individual's chance of developing the disease.

Factors increasing the risk of thyroid cancer may include:

  • Inherited genetic conditions, such as a mutation of the RET gene, familial adenomatous polyposis (FAP), Gardner syndrome, Cowden disease and Carney complex type 1
  • Family history of thyroid cancer in a parent or sibling
  • Low-iodine diet
  • Radiation exposure, including from radiation therapy

Learn about risk factors for thyroid cancer

Who gets thyroid cancer?

Thyroid cancers occur about three times more frequently in women than men. Women also tend to develop thyroid cancer at an earlier age, in their 40s and 50s, compared to men, who usually develop the disease in their 60s or 70s.

Thyroid cancer is seen less frequently in the United States than in some other countries. One risk factor, a low-iodine diet, doesn’t usually impact American patients, since iodine is regularly added to salt and other foods in the United States.

Up to 30 percent of thyroid cancer patients may develop cancer recurrence. Of those, about 80 percent have thyroid cancer recur in the neck area. The other 20 percent have thyroid cancer that metastasizes to other parts of the body, such as the lungs, liver and bones.

Thyroid cancer types

There are several different types of thyroid cancer, which are classified based on how similar they look to normal thyroid cells under a microscope and by the type of cell from which they develop.

Types of thyroid cancer may include:

  • Papillary thyroid cancer, the most common thyroid carcinoma, which forms from follicular cells
  • Follicular thyroid cancer, which is a differentiated thyroid cancer, meaning the cancer cells resemble normal thyroid cells
  • Hürthle cell thyroid cancer, also called oxyphil cell carcinoma, which is a subtype of follicular carcinoma
  • Medullary thyroid cancer, a carcinoma that develops from C-cells in the thyroid gland, including familial medullary thyroid cancer (FMTC) and multiple endocrine neoplasia type 2 (MEN 2)
  • Anaplastic thyroid cancer, which is the most undifferentiated type of thyroid carcinoma, meaning the thyroid tumor cells look more like cancer cells than normal cells

Learn more about thyroid cancer types

Thyroid cancer symptoms

The most common sign of thyroid cancer in the disease's early stages is an unusual lump or nodule, or an enlarged thyroid (goiter) in the neck. Most thyroid nodules are benign, but it is important to have unusual growths examined by a health care professional.

Besides a neck lump, other symptoms of thyroid cancer may include:

  • Fatigue
  • Hoarseness
  • Swollen glands in the neck
  • A cough that persists and is not caused by a cold
  • Neck pain, often starting in the front of the neck
  • Voice changes
  • Difficulty breathing
  • Trouble swallowing

Learn more about thyroid cancer symptoms

Diagnosing thyroid cancer

Tests used for diagnosing thyroid cancer may include:

  • Biopsy, a sample of thyroid tissue or thyroid cells obtained either through a fine-needle aspiration (FNA) or an incisional biopsy, usually performed in an operating room under general anesthesia
  • X-ray
  • Computed tomography scan (CT scan)
  • Magnetic resonance imaging (MRI)
  • Nuclear medicine scan (also called a thyroid scan)
  • Positron emission tomography (PET)/CT scan
  • Ultrasound
  • Advanced genomic testing
  • Blood tests, such as a thyroid function test; level tests of the thyroid-stimulating hormone (TSH), triiodothyronine (T3) and thyroxine (T4); or a level test of the protein thyroglobulin
  • Laryngoscopy

Learn about tests used to diagnose thyroid cancer

Thyroid cancer treatments

According to the American Cancer Society, the five-year survival rate for thyroid cancer ranges from 78 percent for cancer that has spread to distant parts of the body to nearly 100 percent for cancer that has not spread beyond the thyroid.

Treatment options for thyroid cancer may include:

  • Chemotherapy
  • Hormone therapy
  • Radiation therapy, including external beam radiation therapy (EBRT), intensity modulated radiation therapy (IMRT), radioactive iodine therapy and TomoTherapy®
  • Lobectomy, thyroid surgery to remove the lobe containing a cancer
  • Thyroidectomy, surgery to remove most (subtotal or near total thyroidectomy) or all (total thyroidectomy) of the thyroid gland
  • Lymph node removal
  • Targeted therapy, including the use of kinase inhibitors, which target specific enzymes that help regulate cell growth, or angiogenesis inhibitors designed to prevent tumors from establishing new blood supplies

Learn about treatment options for thyroid cancer