The thyroid is a butterfly-shaped organ located below the Adam's Apple, at the base of the throat. The thyroid is an endocrine gland, whose function is to produce produces hormones that help the body use oxygen and calories for energy,and regulation of metabolism, among many functions.
Thyroid cancer is not common, but it is the most common cancer of the endocrine gland.
Thyroid malignancy accounts for only 1.2% of all new cancers (outside skin cancers) in the United States annually.
Prevalence of Thyroid Cancer
Some people refer to thyroid cancer as a "good cancer," primarily because it has very high survival rates. Thyroid cancer is still a cancer that requires treatment and lifelong monitoring, however, and can have debilitating effects on patients. Survival rates, are, however, high, with 95% of all thyroid cancer patients achieving what would be considered a cure, or long-term survival without reoccurrence.
It's estimated that this year, there will be almost 26,000 new cases of thyroid cancer in the U.S. -- 19,190 in women and 6,500 in men -- and an estimated 1,500 people are expected to die of thyroid cancer in 2005.
While rare, thyroid cancer is actually one of the few cancers that are becoming more common in the past several years, with a growth rate of 3% per 100,000 people each year.
Who Gets Thyroid Cancer?
Thyroid cancer affects women two to three times more than men. Besides what appears to be a hormonal or gender connection, the causes of thyroid cancer are, for the most part, not known. There is a link between people who received childhood radiation to the head and neck and an increased risk for thyroid cancer. In addition, exposure to nuclear radiation (such as happened during and after the Chernobyl nuclear accident) can also increase the risk of thyroid cancer fairly dramatically. Some forms of thyroid cancer also appear to be hereditary or genetic and run in families.
When Does Thyroid Cancer Appear?
The median age at diagnosis for papillary thyroid cancer is approximately 40 for women, and 45 for men. The average age for onset of follicular cancer is 48 for women and 53 for men. Anaplastic thyroid carcinoma is more common in sixties and seventies, and is more commonly seen in those who have had goiter or a previous case of papillary or follicular thyroid cancer.
Symptoms of Thyroid Cancer
Typically, if there's any symptom at all, it will more likely be a lump, nodule or swelling in the thyroid. Read Could You Have Thyroid Cancer? Take the Thyroid Neck Check Now for help on how to do a self-check.
Nodules are generally common in the population, however, and do not necessarily indicate cancer. In fact, 95% of thyroid nodules are considered benign - not cancerous.
Many people with thyroid cancer are symptomless, however. Those who do report symptoms often note:
- hoarsening of the voice
- neck pain / discomfort
- difficulty swallowing
- swollen lymph nodes.
There are four types of thyroid cancer: Papillary, Follicular, Medullary, and Anaplastic.
- About 75% of Thyroid Cancers are Papillary and Papillary/follicular
- About 15% are Follicular and Hurthle cell
- About 7% are Medullary
- About 3% are Anaplastic
Follicular cancer, the second most common type of thyroid cancer, is considered to be somewhat more malignant than papillary. The thyroid gland is comprised of follicles which produce thyroid hormones that are essential for growth and development of all body tissues. This cancer doesn't usually spread to the lymph nodes, but it may spread to arteries and veins of thyroid gland and more distantly (lung, bone, skin, etc), though that is uncommon. Follicular cancer is more common in older people. Again, the long -term survival rate is high.
Medullary thyroid cancer is the third most common type of thyroid cancer, and usually originates in the upper central lobe of the thyroid. It spreads to the lymph nodes earlier than papillary or follicular cancers. It differs from papillary and follicular cancer, however, in that it does not arise from cells that produce thyroid hormone, but instead from C cells. These C cells make the hormone calcitonin. This type of cancer can run in families, and also has a good cure rate.