Thyroid cancer is a malignancy that develops in the thyroid gland. It is a rare form of the disease, but is highly treatable if detected in its early stages.
It is estimated that approximately 48,000 new cases of thyroid cancer are diagnosed annually, affecting approximately 36,000 women and 11,000 men.
(also see: Thyroid Cancer Symptoms)
Types of Thyroid Cancer
There are four types of thyroid cancer:
- Papillary: The most common type of thyroid cancer, diagnosed in approximately 75 percent of patients—mainly young females.
- Follicular: Diagnosed in 10-20 percent ofpatients, this type of cancer tends to metastasize, or spread, to the lungs or bones.
- Medullary: Diagnosedin approximately 5-10 percent of patients.
- Anaplastic: This is a very aggressive form of thyroid cancer with a poor prognosis. Less than 14 percent of patients diagnosed experience a 10-year survival rate, mainly because the disease is not known to respond well to treatment.
Stages of Thyroid Cancer
The following progression occurs in papillary and follicular thyroid cancers:
- Stage I (in patients under 45): The tumor may be any size, be found in any part of the thyroid, or may have spread to surrounding tissue or the nearby lymph nodes, but not to any other part of the body.
- Stage II (in patients under 45): The tumor is any size, can be found in any part of the thyroid, and has spread to other parts of the body, especially the lungs or bones
- Stage III (in patients 45 and over): The tumor is larger than 4 centimeters and has not spread beyond the thyroid; the tumor is any size and has spread to the surrounding tissue but not the lymph nodes; the tumor is any size and has spread to the trachea or larynx
- Stage IV (in patients 45 and over): The tumor is any size and has likely spread to other areas of the body, including the surrounding tissue and lymph nodes or bones, lungs, or spinal cord.
Stages of Medullary Thyroid Cancer
Stage 0: Cancer is detected through a screen; no tumor is found.
Stage I: Tumor is found in the thyroid and is less than 2 centimeters.
Stage II: Tumor of larger than 2 centimeters id found in the thyroid and/or the tumor has spread to surrounding tissue (other than the lymph nodes)
Stage III: Tumor is any size and/or has spread tothe lymph nodes near the trachea and possibly surrounding tissue
Stage IV: Tumor is any size and has likely spread to tissue under the skin, spinal cord fluid, carotid artery, lungs, bones, or lymph nodes.
Stages of anaplastic thyroid cancer
This form of the disease is considered to be stage IV and metastasizes throughout the body very quickly.