This year, an estimated 37,340 adults (8,930 men and 28,410, women) in the United States will be diagnosed with thyroid cancer. It is estimated that 1,590 deaths (680 men and 910 women) from the disease will occur this year.
In the United States, women are almost three times more likely than men to develop thyroid cancer; thyroid cancer is the seventh most common cancer in women. It is most commonly diagnosed between the ages of 20 and 55.
Thyroid cancer begins in the thyroid gland. The thyroid gland, also called the thyroid, is located at the front of the neck just below the larynx. It is slightly larger than a quarter and shaped like a butterfly, with a right lobe and a left lobe. The thyroid gland contains mainly two types of cells -- thyroid follicular cells and C cells.
The thyroid is an important part of the endocrine system, the system of organs and glands that regulates specific body functions. The thyroid uses iodine, a mineral found in some foods and in iodized salt, to help make several hormones. Thyroid hormones control the body's heart rate, blood pressure, temperature, and the rate at which food is turned into energy in a process known as metabolism.
Thyroid cancer begins when the cells in the thyroid gland begin to change and grow uncontrollably, until they form a nodule, also called a thyroid tumor. There are two types of thyroid nodules: benign (noncancerous) and malignant (cancerous). Ninety percent of all thyroid nodules are benign.
There are four main types of thyroid cancer:
- Papillary Thyroid Cancer
Accounting for about 80 percent of all thyroid cancers in the US, papillary thyroid cancer is by far the most common type. It begins in the follicular cells of the thyroid and grows slowly. If diagnosed early, most people with papillary thyroid cancer can be cured.
- Follicular Thyroid Cancer
Follicular thyroid cancer also begins in the follicular cells of the thyroid. It accounts for 10 to 15 percent of thyroid cancers. It grows slowly and if diagnosed early can usually be treated successfully.
- Medullary Thyroid Cancer (MTC)
A rare type of thyroid cancer, MTC begins in the C cells of the thyroid. The C cells make an important hormone called calcitonin, which is used as a marker for the activity of medullary cancer. MTC usually grows slowly. It is easier to treat if it is diagnosed before it has spread to other parts of the body.
- Anaplastic Thyroid Cancer
Anaplastic thyroid cancer begins in the follicular cells of the thyroid gland. It is a rare and aggressive cancer that usually grows and spreads very quickly. Anaplastic thyroid cancer is very difficult to control.
