Thyroid CancerThe thyroid gland is located in the lower front of the neck, below the voice box (larynx) located in the upper part of the neck, and above the collarbones. Thyroid cancer (carcinoma) usually appears as a painless lump in this area. In most cases, the lump affects only one side, and the results of thyroid function tests (blood tests) are usually normal.
Many patients with thyroid cancer have no symptoms whatsoever. A lump on the thyroid gland may be found by chance on a routine physical exam or an imaging study of the neck done for unrelated reasons. Other patients feel a gradually enlarging lump in the front portion of the neck or have difficulty swallowing or speaking. Occasionally, the lump may cause a feeling of pressure or shortness of breath. Finding a lump in the neck should be brought to the attention of your physician, even in the absence of symptoms.
Causes and Risk Factors
The exact reason nodules grow in the thyroid gland is not known. But these factors increase the risk:
- Family History. If a parent or sibling had a thyroid nodule, the chance of developing a nodule is increased
- Age. The risk of developing a nodule increases as you age.
- Gender. Woman develop nodules more often than men
- Thyroiditis. Nodules are more likely to form in people who have chronic inflammation of the thyroid gland.
- Radiation exposure to the head or neck. Babies, children and teenagers were treated with radiation for birthmarks, acne or enlarged tonsils in the 1940s and 1950s. People who had these treatments have an increased risk. Exposure to nuclear power plant accidents (for example, the 1986 nuclear power plant explosion in Cherynobyl), or radioactive particles released into the air during atomic weapons testing also increases the risk.
Thyroid Cancer Types
- Papillary thyroid cancers account for about 80 to 90 percent of all cases.
- Papillary tumors develop more often during 30 to 60 years of age.
- They occur three times more often in women than in men.
- The cure rate is usually 97 percent or better.
- Papillary tumors often spread to lymph nodes in the neck (about 25 percent of the time), but rarely spread to distant organs.
- Distant metastases to lung, bones and other sites are rare (<3 percent at time of initial diagnosis).
Follicular Thyroid Carcinoma (including Hurthle Cell Carcinoma)
- Follicular thyroid cancers are the second most common thyroid cancer, comprising about 15 percent of total cases.
- Follicular thyroid cancers usually develop during 40-60 years of age.
- They occur three times more often in women than men.
- The cure rate is typically 90 percent or better.
- Metastasis to the lymph nodes is less common than in papillary cancers
- Metastasis to distant organs (for example. lungs, bones, brain, or liver) is more common than with papillary carcinoma.
- Medullary thyroid cancers are a rare type of thyroid cancer and accounts for about three to five percent of all thyroid cancer cases.
- It occurs more often in older adults.
- Metastasis to the lymph nodes is common at the time of diagnosis.
- Prognosis varies depending on extent of disease at time of diagnosis and post-operative calcitonin levels.
- Anaplastic tumors are the least common type of thyroid cancer, making up only one percent of all thyroid cancer cases.
- The tumors grow rapidly, are difficult to treat and the cure rate is very low.
- The average age of onset is 65 years of age and older.
- Men are two times more likely than women to have anaplastic cancer.
- The prognosis is generally poor due to the aggressive nature of these cancers.
A combination of symptoms, medical history, physical exams and tests are used to determine a diagnosis. Thyroid nodules are often found during a routine physical examination. Your doctor might feel an abnormal lump on the front of your neck.
- The TSH blood test measures a pituitary gland hormone that stimulates the thyroid gland. If the TSH level is increased, the thyroid gland may not be functioning properly. Additional blood tests are needed to measure other thyroid hormones. Both pituitary and thyroid tests are required to confirm that the problem is located in the thyroid gland. Click here for more information on blood work for thyroid diagnostics.
- Thyroid ultrasound uses painless sound waves to create an image of the thyroid gland and identify nodules. Ultrasound can show if a nodule is solid or a fluid-filled cyst, but it cannot determine if a nodule is benign or malignant.
Ultrasound Guided Fine Needle Aspiration Biopsy
- Fine Needle Aspiration Biopsy (FNA). A needle is placed into the thyroid nodule, the cells are aspirated, and then examined under a microscope to determine if a nodule is cancerous.
Treatment and Follow-up Care
Radioactive iodine treatment is given to many patients with thyroid cancer after the tumor is removed. Your endocrinologist will work closely with you to determine if this is the best course of action for you and will go over in detail what other treatment and follow up care is needed.
Your endocrinologist will start you on thyroid hormone replacement medication after surgery. Blood tests will be done periodically to monitor the correct dosage of medication to ensure your blood levels are at the optimal level to decrease chances of thyroid cancer recurrence and to help you feel your best.
Follow up care may also involve other imaging studies such as ultrasounds, MRI, CT, PET and/or iodine scans but your endocrinologist will discuss this with you if needed.