Thyroid cancer is the most common form of cancer of the endocrine system, an intricate communication system that uses specialized chemicals called hormones to send messages that control and coordinate various bodily functions. In addition to the thyroid, the endocrine system includes the hypothalamus, pancreas, sex organs, and the pituitary, adrenal, and pineal glands.
There are four types of thyroid cancer; however, 80 percent are papillary thyroid cancers, which begin in the cells that make thyroid hormones.
The thyroid is a tiny gland in the neck that makes hormones and controls:
- Heart rate
- Blood pressure
- Body temperature
The National Cancer Institute predicts more than 44,000 people will develop thyroid cancer in 2010. Fortunately, thyroid cancer is slow growing, and when caught early, it’s usually curable.
Causes, Incidence, And 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 include:
- Age (over 45)
- Being female
- Iodine, which is commonly found in shellfish and iodized salt.
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.
The most common symptoms of thyroid cancer include:
- A lump in the front of the neck
- Hoarseness or voice changes
- Swollen lymph nodes
- Trouble swallowing or breathing
- Pain in the throat or neck
The American Thyroid Association recommends surgery for all cancerous thyroid tumors than are one centimeter or larger. Following surgery, most patients must take replacement hormone pills for the rest of their lives. Thyroid cancer patients may also undergo external radiation therapy, hormone therapy, radioactive iodine, chemotherapy, or some combination of these treatments.
Scientists have uncovered some of the genetic mutations that activate an important signaling pathway involved in the onset and development of cancers. This knowledge helps researchers develop new treatments.
Recently they’ve identified two targeted agents (drugs) that show promise in thyroid treatment. Understanding the genetic implications also helps physicians more accurately diagnose thyroid cancer and make better prognostic predictions.
While it’s still not common, the incidence of thyroid cancer is increasing. If you experience any of the symptoms described above, see your physician promptly to rule out cancer.