Thyroid Cancer

There are about 20,000 new cases of thyroid cancer each year in the United States. Females are more likely to have thyroid cancer at a ratio of three to one. Thyroid cancer can occur in any age group, although it is most common after age 30 and its aggressiveness increases significantly in older patients. The majority of patients present with a nodule on their thyroid which typically does not cause symptoms. Remember, over 99% of thyroid nodules are not cancer! But, when a thyroid cancer does begin to grow within a thyroid gland, it almost always does so within a discrete nodule within the thyroid.

What Is Thyroid Cancer?

The thyroid gland is located under the Adam's apple in the front part of the neck. In most people, it cannot be seen or felt. It is butterfly shaped, with 2 lobes - the right lobe and the left lobe - joined by a narrow isthmus (see diagram).

The thyroid gland makes a hormone (called thyroid hormone), which is important for many body functions. The production of this hormone depends on iodine, and the thyroid gland absorbs iodine from the blood.

Thyroid hormone regulates a person抯 metabolism. Too much hormone causes a person to be hyperactive, feel nervous, warm, hungry, and often lose weight. Too little hormone causes a person to slow down, feel tired and gain weight. All this is regulated by the pituitary gland, at the base of the brain, which produces a substance called thyroid stimulating hormone (TSH)

The thyroid gland contains mainly 2 types of cells:

§ Thyroid follicle cells actually make and store thyroid hormone. They also make a special thyroid protein called thyroglobulin.

§ C cells make another hormone, calcitonin, which helps regulate the body抯 calcium metabolism.

Different cancers develop from each kind of cell. The differences are important because they determine the seriousness of the cancer and the type of treatment needed.