Thyroid cancer: Overview, Causes

Definition

Thyroid cancer is a cancerous growth of the thyroid gland.

Overview, Causes, & Risk Factors

Thyroid cancer can occur in all age groups.

People who have had radiation therapy to the neck are at higher risk. Radiation therapy was commonly used in the 1950s to treat enlarged thymus glands, adenoids and tonsils, and skin disorders. People who received radiation therapy as children are at increased risk for getting thyroid cancer.

Other risk factors are a family history of thyroid cancer and chronic goiter.

There are several types of thyroid cancer:

  • Anaplastic carcinoma (also called giant and spindle cell cancer) is the most dangerous form of thyroid cancer. It is rare, and does not respond to radioiodine therapy. Anaplastic carcinoma spreads quickly and invades nearby structures such as the windpipe (trachea), causing breathing difficulties.
  • Follicular carcinoma accounts for about 30% of all cases and is more likely to come back and spread.
  • Medullary carcinoma is a cancer of nonthyroid cells that are normally present in the thyroid gland. This form of the thyroid cancer tends to occur in families. It requires different treatment than other types of thyroid cancer.
  • Papillary carcinoma is the most common type, and usually affects women of childbearing age. It spreads slowly and is the least dangerous type of thyroid cancer.

Pictures & Images

Endocrine glands

Endocrine glands release hormones (chemical messengers) into the bloodstream to be transported to various organs and tissues throughout the body. For instance, the pancreas secretes insulin, which allows the body to regulate levels of sugar in the blood. The thyroid gets instructions from the pituitary to secrete hormones which determine the pace of chemical activity in the body (the more hormone in the bloodstream, the faster the chemical activity; the less hormone, the slower the activity).

Thyroid cancer – CT scan

Thyroid cancer - CT scanThis CT scan of the upper chest (thorax) shows a malignant thyroid tumor (cancer). The dark area around the trachea (marked by the white U-shaped tip of the respiratory tube) is an area where normal tissue has been eroded and died (necrosis) as a result of tumor growth.

hyroid gland

Thyroid gland

The thyroid gland, a part of the endocrine (hormone) system, plays a major role in regulating the body’s metabolism.


Review Date : 2/12/2009
Reviewed By : David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; Yi-Bin Chen, MD, Leukemia/Bone Marrow Transplant Program, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

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