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Thyroid Nodules & Cancer
What are thyroid tumors?
The thyroid gland is located in the front of the neck at the base of the throat. Thyroid tumors are either benign (noncancerous) or malignant (cancerous) growths. Examples of benign tumors are adenomas, which may secrete thyroid hormone. Malignant tumors are more rare and are more common in women than in men. According to the American Cancer Society (ACS), about 48,000 cases of thyroid cancer are expected to be diagnosed in the US in 2011.
What are thyroid adenomas?
Thyroid adenomas are small growths (nodules) that start in the cell layer that lines the inner surface of the thyroid gland. The adenoma itself may secrete thyroid hormone. If the adenoma secretes enough thyroid hormone, it may cause hyperthyroidism. Thyroid adenomas may be treated if they cause hyperthyroidism. Treatment may include surgery to remove part of the thyroid (the overactive nodule).
What are cancerous thyroid tumors?
Cancer of the thyroid occurs more often in people who have undergone radiation to the head, neck, or chest. However, it may occur in people without any known risk factors. Most thyroid cancer can be cured with appropriate treatment. Thyroid cancer usually appears as nodules within the thyroid gland.
Some signs that a nodule may be cancerous include:
Presence of a single nodule rather than multiple nodules
Thyroid scan reveals the nodule is not functioning
Nodule is solid instead of filled with fluid (cyst)
Nodule is hard
Nodule grows fast
What are the symptoms of thyroid cancer?
The first sign of a cancerous nodule in the thyroid gland is usually a painless lump in the neck. Other symptoms may include:
Hoarseness or loss of voice as the cancer presses on the nerves to the voice box
Difficulty swallowing as the cancer presses on the throat
Throat or neck pain that does not go away
A cough that does not go away
However, the symptoms of thyroid cancer may resemble other conditions or medical problems. Always consult your physician for a diagnosis.
Thyroid cancer is more common in people who have a history of exposure to radiation, have a family history of thyroid cancer, or personal history of thyroid cancer in the past. However, for most patients, there is no specific reason for the development of thyroid cancer. Although thyroid nodules are very common (up to 50% of females by the age of 50 will have nodules), less than 1 in 10 harbor thyroid cancer.
How is thyroid cancer diagnosed?
In addition to a complete medical history and medical examination, diagnostic procedures for thyroid cancer may include:
- Thyroid scan
- Biopsy – taking a sample of the nodule with a fine needle for examination
There are five main forms of thyroid cancer:
Papillary thyroid cancer: Papillary thyroid cancer is the most common form of thyroid cancer, accounting for about 80 percent of all cases. This form of thyroid cancer affects more women than men. Papillary thyroid carcinoma tends to grow slowly and to spread first to lymph nodes in the neck. Unlike some other tumors, the generally excellent outlook for papillary cancer is usually not affected by spread of the cancer to the lymph nodes.
Follicular thyroid cancer: Follicular thyroid cancer accounts for about 10 percent of thyroid cancer cases. This type of thyroid cancer is more aggressive and tends to spread through the bloodstream into distant organs, particularly the lungs and bones. Preoperative diagnosis by FNA biopsy is very difficult to establish and surgery is needed for ultimate diagnosis. Still, the prognosis (outlook) is very good in most cases.
Hurthle cell cancer: Hurthle cell cancer makes up less than 5% of all thyroid tumors. In the past, it was part of Follicular thyroid cancer, but because the outcome is slightly worse, it was classified as a separate entity. It is spread by blood but also can spread to neck lymph nodes. As with Follicular thyroid carcinoma, preoperative diagnosis by FNA biopsy is very difficult to establish and surgery is needed for ultimate diagnosis.
Anaplastic thyroid cancer: Anaplastic thyroid cancer is the most advanced and aggressive thyroid cancer and is the least likely to respond to treatment. Even when diagnosis is established, surgery is less likely to provide any cure and chemotherapy or radiation is indicated. Fortunately, anaplastic thyroid carcinoma is rare and found in less than 1% of patients with thyroid cancer.
Medullary thyroid cancer: Medullary thyroid cancer accounts for about 4 percent of thyroid cancers. It tends to spread through the lymphatic system (which consists of a system of vessels that connect lymph nodes throughout the body) and the bloodstream to other parts of the body. This type of cancer produces excessive amounts of calcitonin, a hormone also produced by the thyroid gland itself. Because medullary cancer tends to run in families, screening tests for genetic abnormalities in the blood cells may be conducted.
Surgery: The primary therapy for all forms of thyroid cancer is surgery. The generally accepted approach is to remove the one half or entire thyroid gland. For some cancers removal of neck lymph nodes is indicated as well. Often the thyroid cancer is cured by surgery alone, especially if the cancer is small. For larger cancers, radioactive iodine therapy can be used as pill given to destroy thyroid cancer cells after removal of the thyroid gland by surgery.
Radioactive Iodine Therapy: This treatment is used to destroy residual thyroid cancer cells with little or no damage to other tissues in the body.
Prognosis of Thyroid Cancer
Overall, the prognosis of thyroid cancer is very good. Generally, the prognosis is better in younger patients than in those over 40 years of age. Patients with papillary carcinoma who have a primary tumor that is confined to the thyroid gland itself have an excellent outlook and complete recovery is achieved in up to 95% of the patients. Still, even those patients who are unable to be cured of their thyroid cancer are able to live a long time and feel well despite their cancer.