The thyroid is a small, butterfly-shaped gland in the throat that controls the body's heart rate, temperature and metabolism. Cancer of the thyroid gland can interfere with that contol, and lead to other complications. Fortunately, thyroid cancer can usually be successfully treated through minimally invasive methods. Thyroid tumors are somewhat common, and most are not cancerous. Cancer can develop as a result of age, exposure to radiation, or having a family history of goiters, cancer or other diseases. The thyroid is made up of follicular cells and C cells, either of which may develop cancer.
Risks Factors for Thyroid Cancer
The following may increase the risk of getting certain types of thyroid cancer:
- Being between 25 and 65 years old
- Being female
- Being Asian or Caucasian
- Having a family history of thyroid disease
- Having a family history of precancerous polyps in the colon
- Carrying an abnormal RET oncogene
- Having a diet low in iodine
Having had radiation treatments to the head and/or neck also increases a person's risk of thyroid cancer.
Types of Thyroid Cancer
There are four types of cancer that develop in the thyroid gland, and one that develops in glands in the neck.
The most common form of thyroid cancer, papillary cancer usually appears as a single mass in one lobe of the thyroid. It is slow-growing, but can spread to the lymph nodes. It is most common in women between 30 and 50 years old.
The second-most-common form of thyroid cancer, follicular cancer usually remains in the thyroid gland. If it does spread, it is often to other parts of the body, such as the lungs and bones, rather than the lymph nodes.
Accounting for about 2 percent of thyroid cancers, medullary cancer develops in the C cells of the thyroid gland. It can run in families, and spread to other parts of the body even before a mass in the thyroid is discovered. The treatment outcome for this type of cancer is usually not as good as it is for papillary and follicular cancers.
A rare form of thyroid cancer, anaplastic cancer accounts for about 1 percent of all cases. It is fast-growing, often spreads to other parts of the body, and is quite difficult to treat. It usually affects people older than 60.
Symptoms of Thyroid Cancer
Symptoms or signs of thyroid cancer include the following:
- A bump or lump in the neck that may grow rapidly
- Swelling in the neck
- Pain in the front of the neck that may run up to the ears
- Hoarseness or other voice changes that do not go away
- Difficulty swallowing
- Wheezing or difficulty breathing
- A constant cough that is not due to a cold can also be a symptom of thyroid cancer.
Diagnosis of Thyroid Cancer
Thyroid cancer can be diagnosed through a series of tests. Once diagnosed, further testing can help determine the cancer's stage and whether it has spread. Diagnostic tests include the following:
- Surgical biopsy
- Ultrasound exam
- CT/CAT scan
- Blood tests
A fine-needle-aspiration biopsy may also be performed to diagnose thyroid cancer.
Treatment of Thyroid Cancer
Surgery is the most common treatment for thyroid cancer. It is the only way to ensure complete removal of cancer cells, and greatly reduce the risk of recurrence. Types of surgery include the following:
- Lobectomy (removal of lobe in which the cancer is found)
- Near-total thyroidectomy (removal of all but a very small part of the thyroid)
- Total thyroidectomy (removal of the entire thyroid)
- Lymphadenectomy (removal of cancerous lymph nodes from the neck)
Additional standard treatments include radiation therapy, chemotherapy, thyroid hormone therapy and targeted therapy. Thyroid cancer may be slow-growing enough to allow treatment to be delayed, although anyone who chooses to postpone treatment should be closely monitored by a physician.