What Is a Thyroid Cancer?

Cancer is a scary word. Few words can evoke the sense of fear and panic that cancer does. Simply hearing the word can cause patients to react emotionally without evaluating the facts. Once patients learn the facts about thyroid cancer, they may be able to approach the diagnosis without undue fear and apprehension. Indeed, the outlook for most patients with thyroid cancer is excellent.

Each year more than 200,000 thyroid nodules-potential cancers are discovered; however, only about 17,000 are actually cancerous. There are approximately 1,300 deaths per year from thyroid cancer, as com­pared to an estimated 40,000 from breast cancer and 31,000 from prostate cancer. It may be reassuring to know that most thyroid nodules are not cancerous and that patients with thyroid cancer are usually cured.

Thyroid Cancer Terminology

A thyroid nodule or growth that is noncancerous is described as benign; a cancerous growth is described as malignant. Another name for thyroid cancer arising from follicular or C cells (parafollicular cells) is thyroid carcinoma. Many thyroid cancers are contained within their capsules, the membranes around thyroid nodules. Some thyroid cancers break through their capsules but are contained within the thyroid gland. A thyroid cancer may also break through the thyroid gland and invade directly into surrounding structures, such as the windpipe (trachea) and esophagus.