Thyroid cancer stages

Making an educated treatment decision begins with the stage, or progression, of the disease. The stage of thyroid cancer is one of the most important factors in evaluating treatment options.

Our cancer doctors use a variety of diagnostic tests to evaluate thyroid cancer and develop an individualized treatment plan. If you have been recently diagnosed, we will review your pathology to confirm you have received the correct diagnosis and staging information, and develop a personalized treatment plan. If you have a recurrence, we will perform comprehensive testing and identify a treatment approach tailored to your needs.

Thyroid cancer in patients younger than 45

The prognosis of a patient under the age of 45 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:

Stage I: 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 II: 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.

TNM system for thyroid cancer

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:

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).

Stages for thyroid cancer

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.

Stage I (stage 1 thyroid cancer): The tumor is 2 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.

Stage II (stage 2 thyroid cancer): The cancer meets one of the following criteria:

• The diameter of the primary tumor ranges from 2 to 4 cm. There are no cancer cells in regional lymph nodes or distant sites in the body.
• The primary tumor is larger than four cm in diameter or has started to grow outside of the thyroid gland. No cancer was found in the lymph nodes or other parts of the body (medullary thyroid cancer only).

Stage III (stage 3 thyroid cancer): The cancer meets one of the following criteria:

• The primary tumor is larger than 4 cm, or has grown outside the thyroid, but has not spread to nearby lymph nodes or beyond (differentiated cancers only).
• The tumor can be any size or be growing outside the thyroid, and has spread to lymph nodes in the neck but no farther.

Stage IV (stage 4 thyroid cancer): This is the most advanced stage of thyroid cancer, is further subdivided depending on where the cancer has spread:

• Stage IVA: 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 IVB: 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 IVC: The thyroid cancer cells have metastasized, or spread to distant sites.

Stage IV anaplastic thyroid cancer (stage 4 anaplastic thyroid cancer): Anaplastic/undifferentiated thyroid cancers are much more aggressive than the other subtypes and are all considered stage IV:

• Stage IVA: 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 IVB: 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 IVC: The cancer cells have spread beyond the thyroid gland to more distant parts of the body.

Recurrent thyroid cancer

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. Recurrent thyroid cancer 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.

Next topic: How is thyroid cancer diagnosed?