The thyroid gland
The thyroid gland is a small, butterfly-shaped organ in the center of the neck just below the Adam's apple. It makes thyroid hormones that help control many functions of your body. These include heart rate, body temperature, blood pressure, and weight. The thyroid also makes a hormone called calcitonin.
Behind the thyroid are four tiny glands called the parathyroid glands. These glands make parathyroid hormone, which works with calcitonin to regulate the amount of calcium in the body.
Thyroid nodules and cancer
A thyroid nodule or tumor can arise when any of the cells that make up the thyroid start to grow in a disorderly fashion. Most of the time, these nodules are benign, meaning they are not cancer. But about 1 in 10 of these nodules is cancerous.
Most cases of thyroid cancer can be completely cured. Nearly 97 out of 100 people diagnosed with thyroid cancer are still alive 5 years after diagnosis.
Types of thyroid cancer
There are four main types of thyroid cancer.
- Papillary thyroid cancer is the most common type. It accounts for about 80 out of 100 thyroid cancers. Most people with this type of thyroid cancer can be cured if it is found early.
- Follicular thyroid cancer accounts for about 15 out of 100 thyroid cancers. If found early, this cancer also usually responds well to treatment.
- Medullary thyroid cancer is the diagnosis in about 3 out of 100 thyroid cancers. Tumor cells arise from thyroid parafollicular cells, or "C-cells." These cells make calcitonin, which plays a role in calcium regulation. This is usually a slow-growing cancer. It is most easily treated if found before it has spread to other parts of the body.
- Anaplastic thyroid cancer makes up about 2 out of 100 thyroid cancers. It occurs mostly in older patients and tends to grow and spread quickly.
Created on 09/23/2008
Updated on 06/03/2011
- National Cancer Institute. Thyroid cancer.
- National Cancer Institute. Surveillance epidemiology and end results (SEER) stat fact sheets: thyroid cancer.
- National Cancer Institute. What you need to know about thyroid cancer.
- Ladenson P, Kim M. Thyroid. In: Goldman L, Ausiello D, eds. Cecil Textbook of Medicine. 23rd edition. Philadelphia, PA: Saunders Elsevier; 2007.