Thyroid cancer is a malignancy (cancerous growth) of the thyroid gland. Thyroid cancer can occur in all age groups. People who have had radiation therapy to the neck are at higher risk. This 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 have a higher incidence of thyroid cancer. Other risk factors are a family history of thyroid cancer and chronic goiter. The disease affects 1 in 1,000 people.
MedlinePlus - Thyroid Cancer