If thyroid cancer is diagnosed, the doctor needs to know the stage, or extent, of the disease to plan the best treatment. Staging is used to find out whether the cancer has spread, and if so, to which parts of the body. Staging for thyroid cancer is complex and depends on many factors include the type of cancer, the person’s age, and the size and extent of the cancer.
Papillary and follicular thyroid cancer in people 45 years and older
Stage I - In stage I papillary and follicular thyroid cancer, cancer is found only in the thyroid and the tumor is 2 centimeters or smaller.
Stage II - In stage II papillary and follicular thyroid cancer, cancer is only in the thyroid and the tumor is 2 to 4 centimeters in size.
Stage III - In stage III papillary and follicular thyroid cancer, either of the following is found:
The tumor is larger than 4 centimeters and only in the thyroid or the tumor is any size and cancer has spread to tissues just outside the thyroid, but not to lymph nodes.
OR
The tumor is any size and cancer may have spread to tissues just outside the thyroid and has spread to lymph nodes near the trachea or the larynx (voice box).
Stage IV - Stage IV papillary and follicular thyroid cancer are divided into stages IVA, IVB and IVC.
- In Stage IVA - Either the tumor is any size and cancer has spread outside the thyroid to tissues under the skin, the trachea, the esophagus, the larynx (voice box) or the recurrent laryngeal nerve (a nerve with two branches that go to the larynx) and cancer may have spread to nearby lymph nodes OR the tumor is any size and cancer may have spread to tissues just outside the thyroid. Cancer has spread to lymph nodes on one or both sides of the neck or between the lungs.
- In Stage IVB - Cancer has spread to the tissue in front of the spinal column or has surrounded the carotid artery or the blood vessels in the area between the lungs and 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 and bones, and may have spread to lymph nodes.
Medullary Thyroid Cancer
Stage 0 - Medullary thyroid cancer is found only with a special screening test. No tumor can be found in the thyroid.
Stage I - Stage I medullary thyroid cancer is found only in the thyroid and is 2 centimeters or smaller.
Stage II - In stage II medullary thyroid cancer, either of the following is found:
The tumor is larger than 2 centimeters and only in the thyroid.
OR
The tumor is any size and has spread to tissues just outside the thyroid, but not to lymph nodes.
Stage III - In stage III medullary thyroid cancer, the tumor is any size, has spread to lymph nodes near the trachea and the larynx (voice box) and may have spread to tissues just outside the thyroid.
Stage IV - Stage IV medullary thyroid cancer is divided into stages IVA, IVB and IVC.
- In Stage IVA - Either the tumor is any size and cancer has spread outside the thyroid to tissues under the skin, the trachea, the esophagus, the larynx (voice box) or the recurrent laryngeal nerve (a nerve with 2 branches that go to the larynx) and cancer may have spread to lymph nodes near the trachea or the larynx OR the tumor is any size and cancer may have spread to tissues just outside the thyroid. Cancer has spread to lymph nodes on one or both sides of the neck or between the lungs.
- In Stage IVB - Cancer has spread to tissue in front of the spinal column 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 and bones, and may have spread to lymph nodes.
Anaplastic Thyroid Cancer is considered Stage IV Thyroid Cancer
Anaplastic thyroid cancer grows quickly and has usually spread within the neck when it is found. Stage IV Anaplastic Thyroid Cancer is divided into stages IVA, IVB and IVC.
- Stage IVA - Cancer is found in the thyroid and may have spread to lymph nodes.
- Stage IVB - Cancer has spread to tissue just outside the thyroid and may have spread to lymph nodes.
- Stage IVC - Cancer has spread to other parts of the body, such as the lungs and bones, and may have spread to lymph nodes.