Thyroid cancer is cancer of the thyroid gland. This gland makes thyroid hormone, and it is found in the front of the neck. Thyroid gland tumors often appear as bumps in the neck, called nodules, usually in the thyroid gland. In most cases, thyroid nodules are not cancerous.
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There are several types of thyroid cancer:
- Papillary carcinoma (most common type)—It usually grows very slowly and often spreads to lymph nodes in the neck. If caught early, this type of thyroid cancer is often curable.
- Follicular carcinoma (second most common type)—It usually stays in the thyroid gland, but can spread to other parts of the body, such as the lungs and bones. It does not usually spread to the lymph nodes. If caught early, this type of thyroid cancer is often curable.
- Anaplastic carcinoma (rare form of thyroid cancer)—It quickly invades the neck and other parts of the body and is often fatal.
Medullary thyroid carcinoma (MTC)—This cancer develops from cells in the thyroid gland called C-cells.
MTC often spreads to the lymph nodes, lungs, or liver before a thyroid nodule has been discovered. There are two types of MTC:
- Sporadic MTC
- Familial medullary thyroid carcinoma (FMTC)
Thyroid lymphoma (rare type of thyroid cancer)—Many cases occur in people who have a disease called
Cancer occurs when cells in the body divide without control or order. Eventually these uncontrolled cells form a growth or tumor. The term cancer refers to malignant growths. These growths can invade nearby tissues including the lymph nodes. Cancer that has invaded the lymph nodes can then spread to other parts of the body.
It is not clear exactly what causes these problems in the cells, but is probably a combination of genetics and environment.
Thyroid cancer is more common in women, and in people aged 30 years and older. Other factors that may increase your chances of thyroid cancer:
- Diet low in iodine
- History of radiation to the head, neck, or chest, especially in infancy or childhood
- Family history of thyroid cancer
- Enlargement of the hands, feet, and facial features—acromegaly
- Sjogren's syndrome
- Exposure to radioactive fallout from nuclear accidents or exposed to nuclear testing area during childhood
Thyroid cancer may cause:
- A lump in the neck, usually over the thyroid
- Neck pain (sometimes going up to the ears)
- Difficulty swallowing
- Difficulty breathing
- Enlarged lymph glands in the neck
The doctor will ask about your symptoms and medical history. A physical exam will also be done. This may include a careful examination of your neck to look for lumps or abnormalities.
Tests may include:
The physical exam, combined with all of your test results, will help to determine the type and stage of cancer you have. Staging is used to guide your treatment plan. Like other cancers, thyroid cancer is staged from I-IV. Stage I is a very localized cancer, while stage IV indicates a spread to other parts of the body
Cancer treatment varies depending on the stage and type of cancer. Options may include:
- Thyroidectomy—Removal of all or part of the thyroid gland.
- Radioactive iodine therapy—Large doses of radioactive iodine are used to destroy the thyroid gland and thyroid cancer without affecting the rest of the body.
- External radiation therapy—To kill cancer cells and shrink tumors. Radiation is directed at the tumor from a source outside the body.
Because the exact cause of thyroid cancer is unknown, early detection and treatment lead to better outcomes. Your doctor may recommend screening tests if you are at high risk for thyroid cancer. For example:
- Have a thyroid exam every 3 years if you are aged 20-39 years old
- Have a thyroid exam every year if you are aged 40 years or older
exposure to radiation is a major risk factor for thyroid cancer, you should:
- Avoid unnecessary exposure to radiation.
- If you have been exposed to radiation of the head, neck, or chest, have frequent checks for thyroid cancer.
General information about thyroid cancer. National Cancer Institute website. Available at:
https://www.cancer.gov/types/thyroid/patient/thyroid-treatment-pdq#link/_1. Updated August 18, 2017. Accessed October 6, 2017.
Papillary thyroid cancer. EBSCO DynaMed Plus website. Available at:
http://www.dynamed.com/topics/dmp~AN~T115275/Papillary-thyroid-cancer. Updated July 24, 2017. Accessed October 6, 2017.
Thyroid cancer. American Cancer Society website. Available at: https://www.cancer.org/cancer/thyroid-cancer.html. Accessed October 6, 2017.
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http://www.dynamed.com/topics/dmp~AN~T116074/Sjogren-syndrome: Liang Y, Yang Z, Qin B, Zhong R. Primary Sjogren's syndrome and malignancy risk: a systematic review and meta-analysis. Ann Rheum Dis. 2014;73(6):1151-1156.
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http://www.dynamed.com/topics/dmp~AN~T576498/Complications-of-obesity: Bhaskaran K, Douglas I, Forbes H, et al. Body-mass index and risk of 22 specific cancers: a population-based cohort study of 5.24 million UK adults. Lancet. 2014;384(9945):755-765.
Last reviewed September 2017 by
EBSCO Medical Review Board Mohei Abouzied, MD, FACP
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
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