Thyroid Cancer Staging

If your biopsy comes back positive for thyroid cancer, your Rocky Mountain Cancer Centers (RMCC) oncology team will need to learn the extent (stage) of the disease in order to help you choose the best treatment. The stage is based on various factors including the size of the nodule, whether the cancer has spread, and if so, to what parts of the body.

The following tests and procedures may be used in the staging process:

• CT scan: An x-ray machine linked to a computer takes a series of detailed pictures of areas inside your body. A CT scan may show whether cancer has spread to lymph nodes, other areas in your neck, or your chest.
• Ultrasound: An ultrasound exam of your neck may show whether cancer has spread to lymph nodes or other tissues near your thyroid.
• MRI: MRI uses a powerful magnet linked to a computer. It makes detailed pictures of tissue. Your doctor can view these pictures on a screen or print them on film. MRI may show whether cancer has spread to lymph nodes or other areas.
• Chest x-ray: X-rays of your chest may show whether cancer has spread to the lungs.
• Whole body scan: You may have a whole body scan to see if cancer has spread from the thyroid to other parts of the body. You get a small amount of a radioactive substance. The substance travels through the bloodstream. Thyroid cancer cells in other organs or the bones take up the substance. Thyroid cancer that has spread may show up on a whole body scan.

Thyroid cancer spreads most often to the lymph nodes, lungs, and bones. When the cancer spreads, the tumor is the same type of cancer as the primary tumor. For example, if thyroid cancer spreads to the lung, the cancer cells in the lung are actually thyroid cancer cells. The disease is metastatic thyroid cancer, not lung cancer. For that reason, it’s treated as thyroid cancer, not lung cancer. Doctors call the new tumor “distant” or metastatic disease.

Stages are used to describe thyroid cancer based on the type of thyroid cancer and the age of the patient:

Papillary and follicular thyroid cancer in patients younger than 55 years

• Stage I: In stage I papillary and follicular thyroid cancer, the tumor is any size and may have spread to nearby tissues and lymph nodes. Cancer has not spread to other parts of the body.
  
• Stage II: In stage II papillary and follicular thyroid cancer, the tumor is any size and cancer may have spread to nearby tissues and lymph nodes. Cancer has spread from the thyroid to other parts of the body, such as the lungs or bones.

Papillary and follicular thyroid cancer in patients 55 years and older

• Stage I: In stage I papillary and follicular thyroid cancer, cancer is found in the thyroid only and the tumor is 4 centimeters or smaller.

• Stage II: In stage II papillary and follicular thyroid cancer, one of the following is found:
  • Cancer is found in the thyroid and the tumor is 4 centimeters or smaller; cancer has spread to nearby lymph nodes; or
  • Cancer is found in the thyroid, the tumor is larger than 4 centimeters, and cancer may have spread to nearby lymph nodes; or
  • The tumor is any size and cancer has spread from the thyroid to nearby muscles in the neck and may have spread to nearby lymph nodes.

• Stage III: In stage III papillary and follicular thyroid cancer, the tumor is any size and cancer has spread from the thyroid to soft tissue under the skin, the esophagus, the trachea, the larynx, or the recurrent laryngeal nerve (a nerve that goes to the larynx). Cancer may have spread to lymph nodes.

• Stage IV: Stage IV papillary and follicular thyroid cancer is divided into stages IVA and IVB.
  • In stage IVA, the tumor is any size and cancer has spread to tissue in front of the spine or has surrounded the carotid artery or the blood vessels in the area between the lungs. Cancer may have spread to lymph nodes.
  
   
  • In stage IVB, the tumor is any size and cancer has spread to other parts of the body, such as the lungs or bones. Cancer may have spread to lymph nodes.

Anaplastic thyroid cancer in patients of all ages

Anaplastic thyroid cancer grows quickly and usually has spread within the neck when it is found. Anaplastic thyroid cancer is considered stage IV thyroid cancer. Stage IV anaplastic thyroid cancer is divided into stages IVA, IVB, and IVC.

• In stage IVA, cancer is found in the thyroid only and the tumor may be any size.

• In stage IVB, one of the following is found:
  • Cancer is found in the thyroid and the tumor may be any size; cancer has spread to nearby lymph nodes; or
  • The tumor is any size and cancer has spread from the thyroid to nearby muscles in the neck and may have spread to nearby lymph nodes; or
  • The tumor is any size and cancer has spread from the thyroid to soft tissue under the skin, the esophagus, the trachea, the larynx, the recurrent laryngeal nerve (a nerve that goes to the larynx), or tissue in front of the spine, or has surrounded the carotid artery or the blood vessels in the area between the lungs; cancer may have spread to lymph nodes.

• In stage IVC, the tumor is any size and cancer has spread to other parts of the body, such as the lungs or bones. Cancer may have spread to lymph nodes.

Medullary thyroid cancer in patients of all ages

• Stage I: In stage I medullary thyroid cancer, cancer is found in the thyroid only and the tumor is 2 centimeters or smaller.

• Stage II: In stage II medullary thyroid cancer, one of the following is found:
  • Cancer is in the thyroid only and the tumor is larger than 2 centimeters; or
  • The tumor is any size and cancer has spread from the thyroid to nearby muscles in the neck.

• Stage III: In stage III medullary thyroid cancer, the tumor is any size and cancer may have spread from the thyroid to nearby muscles in the neck. Cancer has spread to lymph nodes on one or both sides of the trachea or larynx.

• Stage IV: Stage IV medullary thyroid cancer is divided into stages IVA, IVB, and IVC. 
  • In stage IVA, either of the following is found:
    • The tumor is any size and cancer has spread from the thyroid to soft tissue under the skin, the esophagus, the trachea, the larynx, or the recurrent laryngeal nerve (a nerve that goes to the larynx); cancer may have spread to lymph nodes on one or both sides of the neck; or
    • The tumor is any size and cancer may have spread from the thyroid to nearby muscles in the neck; cancer has spread to lymph nodes on one or both sides of the neck.
   
  • In stage IVB, the tumor is any size and cancer has spread to tissue in front of the spine or to the spine or has surrounded the carotid artery or the blood vessels in the area between the lungs. Cancer may have spread to lymph nodes.
   
  • In stage IVC, the tumor is any size and cancer has spread to other parts of the body, such as the lungs or liver. Cancer may have spread to lymph nodes.

Recurrent Thyroid Cancer

Unfortunately, thyroid cancer can come back after it has been treated. This is called recurrent cancer. Recurrent cancers typically happen because undetected cancer cells remained somewhere in your body after treatment. If your thyroid cancer returns, it could come back in the thyroid itself or in other parts of your body.