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Diagnosis and Prognosis of Thyroid Cancer

by Rosalyn Carson-DeWitt, MD
En Español (Spanish Version)
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Thyroid cancer may not have symptoms. Your doctor may notice changes to your thyroid during a normal physical exam. Something may also be found during a scan for another health issue. You may also be asked about you and your family's health history.

Suspicion of Thyroid Cancer

There are other conditions that can cause a change in the thyroid. They are more common and often easier to treat. Tests will need to be done to see if the changes may be due to cancer. Tests may include:

  • Blood tests —To look for signs of a tumor growth. Thyroid hormones, calcitonin, and calcium levels can also be measured with blood tests. They can show a change in thyroid function.
  • Imaging tests —To locate tumor and see its size. Imaging tests may include:

Diagnosis of Thyroid Cancer

A biopsy is needed to confirm cancer. A sample of tissue from the growth will be taken. It will be checked under a microscope for cancer cells.

The procedure will depend on the type, size, and location of the growth. Options include:

  • Fine needle aspiration (FNA)—A thin needle is used to remove cells and fluid from the area.
  • Core needle—A larger, hollow needle is used to remove a wider area of tissue.
  • Surgical—The entire growth is removed.
  • Lobectomy—The lobe with the growth is removed.

Staging of Thyroid Cancer

The results from a number of tests will help to know the stage of cancer. The stage is used to help make a treatment plan. Staging is based on how far the tumor has spread, what lymph nodes are involved, and if the cancer has spread to other tissue. Information about the cancer cells themselves will also be needed.

Staging Tests

Tests that may help determine thyroid cancer stage include:

  • Blood tests—To look for changes in blood cells, proteins, or signs of cancer.
  • Imaging tests—To show how much of the thyroid is affected. It can also show if lymph nodes or nearby tissue is involved or if it has spread to other areas of the body. Imaging tests may include:
  • Laryngoscopy—A tube is passed into the throat. It will help the doctor see any changes to throat. It can show if cancer has spread to throat.
  • Sentinel lymph node biopsy—Sentinel lymph nodes are the first nodes that a tumor will drain into. If these nodes are free of cancer cells, it is unlikely that the cancer has spread. If cancer cells are present, then more lymph nodes may need to be removed to see how far the cancer has spread.
  • Tissue evaluation—Cancer tissue from the biopsy will be more closely examined. Cancer cells have factors that may make them more or less vulnerable to treatments.

Stages of Thyroid Cancer

There are different types of thyroid cancer. The type and microscopic details are important for the cancer stage and the treatment plan.

Papillary and Follicular Thyroid Cancer

In people under 45 years old, papillary and follicular thyroid cancers are staged from I- II:

  • Stage I —Any size tumor that MAY be found in nearby structures and lymph nodes. It HAS NOT spread to other parts of the body.
  • Stage II —Any size tumor that HAS spread beyond the thyroid gland to other parts of the body. The most common sites for thyroid cancer to spread are the lymph nodes in other parts of the body, the bones, and the lungs.

In people aged 45 years and older, papillary and follicular thyroid cancers are staged from I-IV:

  • Stage I —The tumor is no larger than 2 centimeters (cm) in size and HAS NOT spread beyond the thyroid gland.
  • Stage II —The tumor is 2-4 cm in size and HAS NOT spread beyond the thyroid gland.
  • Stage III —Any of the following:
    • The tumor is larger than 4 cm in size and HAS NOT spread beyond the thyroid gland OR is any size and HAS spread just beyond the thyroid gland BUT IS NOT in nearby lymph nodes
    • The tumor is any size AND MAY be found beyond the thyroid gland in nearby lymph nodes adjacent to the trachea or the larynx.
  • Stage IVA —Any of the following:
    • The tumor is any size AND IS found beyond the thyroid gland in either the esophagus, under the skin, the larynx (or laryngeal nerve), trachea, AND MAY be in nearby lymph nodes adjacent to the trachea or larynx.
    • The tumor is any size AND MAY be found beyond the thyroid gland AND is found in nearby lymph nodes around the neck (either or both sides) or between the lungs.
  • Stage IVB —The tumor is found beyond the thyroid gland near the spinal column or around the carotid artery (in the neck), or the blood vessels between the lungs, AND MAY be in the lymph nodes.
  • Stage IVC —The tumor is found beyond the thyroid gland. The most common sites for thyroid cancer to spread are the lymph nodes in other parts of the body, the bones, and the lungs.

Medullary Thyroid Cancer

Medullary thyroid cancer is staged from 0-IV:

  • Stage 0 —There is no tumor present, but cancer is found by specific screening tests.
  • Stage I —The tumor is no larger than 2 centimeters (cm) in size and HAS NOT spread beyond the thyroid gland.
  • Stage II —Any of the following:
    • The tumor is larger than 2 cm in size and HAS NOT spread beyond the thyroid gland.
    • The tumor is any size and HAS spread just beyond the thyroid gland BUT NOT to nearby lymph nodes.
  • Stage III —The tumor is any size AND MAY be found beyond the thyroid gland AND nearby lymph nodes adjacent to the trachea and larynx.
  • Stage IVA —Any of the following:
    • The tumor is any size AND IS found beyond the thyroid gland in either the esophagus, under the skin, the larynx (or laryngeal nerve), trachea, AND MAY be in nearby lymph nodes adjacent to the trachea or larynx.
    • The tumor is any size AND MAY be found beyond the thyroid gland AND is found in nearby lymph nodes around the neck (either or both sides) or between the lungs.
  • Stage IVB —The tumor is found beyond the thyroid gland near the spinal column, or around the carotid artery (in the neck), or the blood vessels between the lungs, AND MAY be in the lymph nodes.
  • Stage IVC —The tumor is found beyond the thyroid gland. The most common sites for thyroid cancer to spread are the lymph nodes in other parts of the body, the bones, and the lungs.

Anaplastic Thyroid Cancer

Anaplastic thyroid cancer is always stage IV:

  • Stage IVA —The tumor is found in the thyroid gland and MAY be in the lymph nodes.
  • Stage IVB —The tumor is found beyond the thyroid gland and MAY be in the lymph nodes.
  • Stage IVC —The tumor is found beyond the thyroid gland. The most common sites for thyroid cancer to spread are the lymph nodes in other parts of the body, the bones, and the lungs.

Prognosis

Prognosis is most often expressed as the percentage of patients who are expected to survive over 5 or 10 years. Cancer prognosis is an inexact science. This is because the predictions are based on the experience of large groups of patients with cancer in various stages. Using this information to predict the future of an individual patient is always imperfect and often flawed, but it is the only method available.

Papillary and follicular thyroid cancers are among the least dangerous cancers when treated. If detected early, nearly all people survive 5 years or more. In those with metastatic cancer, survival rates are about 55%.

Medullary thyroid cancers have similar survival rates except if metastatic cancer is present. In this case, about 25% of all people survive 5 years or more.

Anaplastic thyroid cancer is the most fatal type. About 10% of all people survive 5 years or more because it spreads rapidly and is difficult to treat. Almost all deaths occur within the first year of diagnosis.

REFERENCES:

Anaplastic thyroid cancer. EBSCO DynaMed website. Available at:http://www.dynamed.com/topics/dmp~AN~T114292/Anaplastic-thyroid-cancer. Updated June 29, 2018. Accessed December 8, 2018.

Follicular thyroid cancer. EBSCO DynaMed website. Available at:http://www.dynamed.com/topics/dmp~AN~T115204/Follicular-thyroid-cancer. Updated June 27, 2017. Accessed December 8, 2018.

Medullary thyroid cancer. EBSCO DynaMed website. Available at:http://www.dynamed.com/topics/dmp~AN~T113756/Medullary-thyroid-cancer. Updated June 29, 2018. Accessed December 8, 2018.

Papillary thyroid cancer. EBSCO DynaMed website. Available at:http://www.dynamed.com/topics/dmp~AN~T115275/Papillary-thyroid-cancer. Updated August 15, 2018. Accessed December 8, 2018.

Stages of thyroid cancer. National Cancer Institute website. Available at: https://www.cancer.gov/types/thyroid/patient/thyroid-treatment-pdq#section/_27. Updated August 18, 2017. Accessed December 8, 2018.

Tests for thyroid cancer. American Cancer Society website. Available at: https://www.cancer.org/cancer/thyroid-cancer/detection-diagnosis-staging/how-diagnosed.html. Updated April 15, 2016. Accessed December 8, 2018.

Thyroid cancers. Merck Professional Version website. Available at: http://www.merckmanuals.com/professional/endocrine-and-metabolic-disorders/thyroid-disorders/thyroid-cancers. Updated July 2016. Accessed December 8, 2018.

Treatment option overview. National Cancer Institute website. Available at: https://www.cancer.gov/types/thyroid/patient/thyroid-treatment-pdq#section/_67. Updated August 18, 2017.Accessed December 8, 2018.

Last reviewed September 2018 by EBSCO Medical Review Board Mohei Abouzied, MD, FACP  Last Updated: 12/18/2020