This page was reviewed under our medical and editorial policy by
Maurie Markman, MD, President, Medicine & Science
This page was updated on June 7, 2022.
Making an educated treatment decision begins with identifying the stage, or progression, of the disease. The stage of thyroid cancer is one of the most important factors in evaluating treatment options.
Cancer doctors use a variety of tests to diagnose thyroid cancer and develops an individualized treatment plan. The care team reviews the pathology to confirm the diagnosis and staging information, and develop a personalized treatment plan. If the patient has a recurrence, the care team performs comprehensive testing and identifies a treatment approach tailored to his or her needs.
The prognosis of a patient under the age of 55 with a differentiated (papillary or follicular) thyroid cancer is good. The thyroid cancer staging system takes this information into account, and classifies these cancers simply into two groups based on whether they have spread to distant organs, listed below.
Stage 1: The primary tumor can be any size and the cancer may or may not have spread to lymph nodes. Distant sites in the body are not affected.
Stage 2: The primary tumor can be any size and the cancer may or may not have spread to lymph nodes, but cancer cells have spread to distant areas of the body.
Cancer staging describes how large a cancer is, and the degree to which the disease has spread. The staging guidelines developed by the American Joint Committee on Cancer (AJCC) are often used to stage thyroid cancers. The stages are based on three categories, listed below.
T (tumor): This describes the primary tumor size.
N (node): This indicates whether the thyroid cancer cells have spread to regional lymph nodes.
M (metastasis): This refers to whether the cancer has metastasized (spread to distant areas of the body).
The thyroid cancer staging classification system is very similar for older patients with differentiated tumors and for those with medullary thyroid cancer. Age is not a consideration when classifying medullary cancers.
The tumor is 2 centimeters (cm) or smaller (less than an inch wide), and has not grown outside the thyroid. It has not spread to nearby lymph nodes or distant sites.
The cancer meets one of the following criteria:
The cancer meets one of the following criteria:
Stage 4, also referred to as metastatic thyroid cancer, is the most advanced stage of the disease. Approximately 30 percent of thyroid cancers are diagnosed after the cancer has spread to regional lymph nodes. About 3 percent of thyroid cancer diagnoses are made after the cancer has spread to distant sites or organs.
Metastatic thyroid cancer stages are further subdivided depending on where the cancer has spread, as described below.
Stage 4A: Cancers at this stage have grown beyond the thyroid gland and may have spread into nearby tissue, or they may have spread to lymph nodes in the neck and upper chest, but not to distant sites.
Stage 4B: The primary tumor has grown into the spine or into nearby large blood vessels. In this thyroid cancer stage, the disease may or may not have spread to lymph nodes, but has not reached distant sites.
Stage 4C: The thyroid cancer cells have metastasized, or spread to distant sites.
Anaplastic/undifferentiated thyroid cancers are much more aggressive than the other subtypes and are all considered stage 4, as described below.
Stage 4A: The primary tumor is contained within the thyroid gland, although it may or may not have spread to nearby lymph nodes. It has not spread to distant organs.
Stage 4B: The tumor has spread outside of the thyroid gland, and cancer cells may or may not have been found in regional lymph nodes, but have not reached distant sites.
Stage 4C: The cancer cells have spread beyond the thyroid gland to more distant parts of the body.
Thyroid cancer cells may travel through the lymphatic system or the bloodstream to other areas of the body. The most common thyroid cancer metastasis sites include:
Even after treatment for thyroid cancer, it is possible for the primary cancer to return. This is called recurrent disease. Recurrent thyroid cancer may occur years after the initial treatment for the disease is completed.
A thyroid cancer recurrence typically occurs in the neck area, such as the lymph nodes. This is called a regional recurrence. Some patients experience distant metastases, or cancer that has spread to other areas of the body. Distant thyroid cancer recurrence typically develops in the bones and lungs.
One way people battling cancer can estimate life expectancy is to review the five-year relative survival rate for that type of cancer. A five-year relative survival rate shows the likelihood that a person with a specific type and stage of cancer may live for at least five years after the diagnosis, compared with people who don't have cancer. The rate includes the life expectancy of patients who are still in treatment and those who have finished treatment and have no further evidence of disease. The overall five-year relative survival rate for thyroid cancer is 98.5 percent.
The National Cancer Institute SEER Program further bases the survival rate for thyroid cancers on how far the cancer has spread:
Localized cancer hasn't spread outside of the thyroid. The five-year survival rate for localized thyroid cancer is about 99.9 percent.
Regional cancer has spread from the thyroid area to nearby lymph nodes. The five-year survival rate for regional thyroid cancer is about 98.3 percent.
Distant cancer has spread to structures that are further away from the thyroid. The five-year survival rate for distant thyroid cancer is about 53.5 percent.
Keep in mind that the survival rate for thyroid cancer depends on a variety of factors, including the patient's age, overall health and the extent of the disease, so always talk to the care team about the patient's individual prognosis.
Next topic: How is thyroid cancer diagnosed?