Thyroid cancer is a cancerous growth of the thyroid, a gland that creates hormones. These hormones regulate heart rate, body temperature, weight, blood pressure, and calcium levels.
Because the thyroid gland is directly below the skin, a lump or nodule can usually be felt by a patient or doctor. Thyroid nodules are found most commonly in older adults; however, only about one in 20 nodules are cancerous.
It is considered one of the least-deadly cancers, but unlike other adult cancers, thyroid cancer is more common among younger adults. Two-thirds of all cases diagnosed are found in people between the ages of 20 and 55, according to the American Cancer Society.
There are several types of thyroid cancer. The most common are the rarely fatal papillary carcinoma and follicular carcinoma. Other less prevalent types are Hürthle cell carcinoma, medullary thyroid carcinoma, anaplastic carcinoma, and thyroid lymphoma.
The National Cancer Institute estimates there will be more than 44,600 new cases of thyroid cancer and nearly 1,700 thyroid cancer-related deaths by the end of 2010. Interestingly, diagnoses of thyroid cancer have doubled since 1990. One theory attributes the trend to an increase in the use of thyroid ultrasounds that detects smaller cancers that may not have been identified in the past.
Symptoms of thyroid cancer are generally contained to the neck and include:
- difficulty swallowing
- persistent hoarseness or other change in the voice
- a lump on the thyroid (nodule) or neck swelling
- neck pain, throat pain
While there is no known cause for thyroid cancer, certain risk factors have been identified. They include:
- being female
- family history
- having a diet low in iodine
- exposure to radiation at high levels
- inherited conditions