Thyroid cancer

Alternative names:

cancer of the thyroid; follicular tumor of the thyroid; tumor - thyroid

Definition:

A malignancy of the thyroid gland.

Causes, incidence, and risk factors:

Thyroid cancer can occur in all age groups, and especially in people who have had radiation therapy to the neck. Radiation therapy was commonly used in the 1950s to treat enlarged thymus glands, adenoids and tonsils, and skin disorders. A higher incidence of thyroid cancer is present in people who received radiation therapy as children. Other risk factors are a family history of thyroid cancer and chronic goiter. The overall incidence is 1 out of 1,000 people.

There are several different types of thyroid cancer. Papillary carcinoma is the most common and usually affects women of child-bearing age. It metastasizes slowly and is the least malignant type of thyroid cancer. Follicular carcinoma accounts for about 30% of all cases and has a greater rate of recurrence and metastasis. Medullary carcinoma can produce symptoms similar to Cushing's syndrome and tends to occur in families. Anaplastic carcinoma (also called giant and spindle cell cancer is the most malignant form of thyroid cancer and does not respond to radioiodine therapy. It metastasizes quickly and invades nearby structures such as the trachea, causing compression and breathing difficulties.