Original Editors - Adam Hooten & Andrew Stethen from Bellarmine University's Pathophysiology of Complex Patient Problems project.
- 1 Definition/Description
- 2 Prevalence
- 3 Characteristics/Clinical Presentation
- 4 Associated Co-morbidities
- 5 Medications
- 6 Diagnostic Tests/Lab Tests/Lab Values
- 7 Etiology/Causes
- 8 Systemic Involvement
- 9 Medical Management (current best evidence)
- 10 Physical Therapy Management (current best evidence)
- 11 Differential Diagnosis
- 12 Case Reports/ Case Studies
- 13 Resources
- 14 Recent Related Research (from Pubmed)
- 15 References
The thyroid gland regulates hormones in the body that control heart rate, blood pressure, weight, and body temperature. Thyroid cancer forms in the thyroid gland and is broken down into four main types: papillary, follicular, medullary, and anaplastic. Papillary thyroid cancer is the most common type and grows slowly in the follicular cells. Follicular thyroid cancer is slightly less common but also grows slowly in the follicular cells. Both forms look similar to normal thyroid tissue under a microscope and account for over 90% of all thyroid cancers. These two forms are often curable when found under the age of 45. Medullary thyroid cancer develops in the C cells and is sometimes the result of a genetic syndrome. This cancer does not resemble normal thyroid tissue and accounts for almost 5% of thyroid cancers. This type can be controlled if it is diagnosed before metastasis. The anaplastic form of thyroid cancer is the least common at 2%, but it is fast growing and harder to treat. Staging your cancer is the process of finding out if and how far a cancer has spread. The stage of a cancer is one of the most important factors in choosing treatment options and predicting your prognosis.
- The most common system used to describe the stages of thyroid cancer is the American Joint Committee on Cancer (AJCC) TNM system. The TNM system is based on 3 key pieces of information:
- T indicates the size of the main (primary) tumor and whether it has grown into nearby areas.
- N describes the extent of spread to nearby (regional) lymph nodes. Lymph nodes are bean-shaped collections of immune system cells to which cancers often spread first. Cells from thyroid cancers can travel to lymph nodes in the neck and chest areas.
- M indicates whether the cancer has spread (metastasized) to other organs of the body. (The most common sites of spread of thyroid cancer are the lungs, the liver, and bones.)
- Numbers or letters appear after T, N, and M to provide more details about each of these factors. The numbers 0 through 4 indicate increasing severity. The letter X means a category can’t be assessed because the information is not available.
- More information on staging can be found at: http://www.cancer.org/cancer/thyroidcancer/detailedguide/thyroid-cancer-staging
Estimated new cases in the United States in 2014: 62,980 (47,790 in women and 15,190 in men).
Estimated deaths in the United States in 2014: 1,890 (1,060 women and 830 men).
Thyroid cancer is more commonly diagnosed at a younger age than most other adult cancers. Nearly 70% of new cases are found in people younger than 55 and about 2% are found in children and teens. Thyroid cancer diagnoses have increased in the recent years and is the most rapidly increasing cancer in the United States. This increase can mostly be attributed to the advances in the thyroid ultrasound which can detect very small thyroid nodules. The death rate for thyroid cancer remains low compared to other cancers. 
Generally, Thyroid cancer does not cause any symptoms, but a person may have a lump or nodule around the thyroid in the neck area. The most common sign of thyroid cancer is a nodule that may be noticed by a physician, or even the patient themselves as they put on a necklace, button a shirt or coat, or looking in the mirror. On rare occasions, thyroid cancer may actually present with symptoms such as pain in the jaw, neck or ear areas. The nodule can compress the airway if it gets large enough wich can lead to difficulty breathing or swallowing and hoarsness. The patient may complain of a "tickle in the throat". 
An associated co-morbidity is a disorder or disease that predisposes a person to develop thyroid cancer.
- Several inherited conditions have been linked to different types of thyroid cancer, including family history. However, most people who develop thyroid cancer do not have an inherited condition or a family history of the disease. 
- Medullary thyroid cancer
- About 1 out of 3 medullary thyroid carcinomas (MTCs) result from inheriting an abnormal gene. These cases are known as familial medullary thyroid carcinoma (FMTC).
- The combination of FMTC and tumors of other endocrine glands is called multiple endocrine neoplasia type 2 (MEN 2). There are 2 subtypes, MEN 2a and MEN 2b, both of which are caused by mutations in a gene called RET.
- In MEN 2a, MTC occurs along with pheochromocytomas (tumors that make adrenaline) and with parathyroid gland tumors.
- In MEN 2b, MTC is associated with pheochromocytomas and with benign growths of nerve tissue on the tongue and elsewhere called neuromas. This subtype is much less common than MEN 2a.
- In the above inherited forms of MTC, the cancers often develop during childhood or early adulthood and can spread early. MTC is most aggressive in the MEN 2b syndrome. If MEN 2a, MEN 2b, or isolated FMTC runs in your family, you may be at very high risk of developing MTC. 
- Other thyroid cancers
- Familial adenomatous polyposis (FAP): Persons with this disorder are at an increased risk for papillary thyroid cancer
- Cowden disease: Can cause an increased risk of thyroid problems and papillary or follicular thyroid cancers
- Carney complex, type I: Can cause an increased risk of papillary or follicular thyroid cancers.
- Familial nonmedullary thyroid carcinoma: Thyroid cancer occurs more often in some families, and is often seen at an earlier age. The most common form of thyroid cancer that runs in these families is the papillary type. Genes on chromosome 19 and chromosome 1 are suspected of causing these familial cancers.
- Family history: Having a first-degree relative (parent or sibling) with thyroid cancer, even without a known inherited syndrome in the family, increases your risk of thyroid cancer. The genetic basis for these cancers is not totally clear.
Below is a list of cancer drugs that are approved by the Food and Drug Administration (FDA) for thyroid cancer. 
Adriamycin PFS (Doxorubicin Hydrochloride)
Adriamycin RDF (Doxorubicin Hydrochloride)
Nexavar (Sorafenib Tosylate)
Diagnostic Tests/Lab Tests/Lab Values
Thyroid cancer is commonly diagnosed using a fine needle aspiration biopsy of a thyroid nodule. The biopsy can also be done after the nodule has been removed during surgery. Thyroid lab test are generally not helpful in the diagnosis of thyroid cancer, the lab tests are usually normal regardless if a cancer is present. 
The cause of thyroid cancer is unknown, however, people who have their thyroid gland exposed to high doses of radiation or have a family history of thyroid cancer are at a higher risk of developing thyroid cancer. The risk of thyroid cancer also increases as we age. High doses of radiation such as from reoccuring chest x-rays, especially in childhood, can lead to thyroid cancer. Treatments and x-rays for Hodgkin's disease and breast cancer have been shown to have a greater risk for thyroid cancer. Generally, exposure form routine x-rays such as a simple chest x-ray and dental x-rays have not been linked to increaseing the risk for thyroid cancer. Radioactive iodine has also been linked to causing thyroid cancer. Examples of radioactive iodine causing thyroid cancer would include Chernobyl, a Russian nuclear power plant accident in 1986 and the tsunami related nuclear power plant disaster in 2011 in Japan. 
The most common places in the body for thyroid cancer to spread to are the lungs, liver, and bones. 
Lungs: Patients with cancer that has spread to the lungs may not have any associated signs and symptoms. Possible symptoms could include the following though: 
- coughing up blood
- chest pain
- shortness of breath
- weight loss
Liver: In the early stages there may not be any signs or symptoms. In the later stages, the liver begins to swell and can cause the following symptoms: 
- loss of appetite
- weight loss
- pain in right shoulder or right upper abdomen
- Bone pain is often the first symptom. Pain is worse at night and is better with movement.
- Broken bones
- Numbness or paralysis
- Loss of appetite, confusion, nausea
Medical Management (current best evidence)
There are various types of treatment options available for those diagnosed with thyroid cancer. There are standard treatments and some that are being tested in clinical trials. There are currently five standard treatments:
1. Surgery- most common form of treatment
- Lobectomy (Removal of the lobe of the lung with the cancer)
- Near-toal thyroidectomy (Removal of nearly all the thyroid gland)
- Total thyroidectomy (Removal of all the thyroid gland)
- Lymphadenectomy (Removal of cancerous lymph nodes in the neck)
2. Radiation therapy (including radioactive iodine therapy or RAI)
- RAI is used for follicular and papillary thyroid cancers. This is taken by mouth and will collect any remaining thyroid cancer cells that may have spread. Since only the thyroid gland takes up iodine, no other tissue is harmed.
- Radiation uses high energy x-rays to kill cancer cells and keep them from growing (depends on stage and type of cancer).
- Uses drugs (by mouth or injection) to stop the growth of cancer cells. (Depends on type and stage of cancer).
4. Thyroid hormone therapy
- Hormone therapy removes hormones or blocks their action to stop cancer cells from growing. For thyroid cancer, drugs are given to prevent the body from making Thyroid-stimulating hormone (TSH) because this hormone increases the chance that the thyroid cancer will grow or recur.
5. Targeted therapy
- Uses drugs or other substances to kill cancerous cells and avoid harming normal cells. Vandetanib, a type of Tyrosine Kinase Inhibitor (TKI), is used to block signals needed for thyroid tumors to grow. 
Patients with thyroid cancer may want to think about participating in a clinical trial. More information can be found at: http://www.cancer.gov/clinicaltrials
Physical Therapy Management (current best evidence)
Exercise has recently been shown through research to be safe and possible during the cancer treatment. Physical Therapy for cancer treatment can include exercises to improve flexibility, strength, and endurance. Massage may also be used to help decrease stress, pain, and scar tissue during and after cancer treatment. It is important to maintain an active lifestyle to help improve quality of life and reduce stress and fatigue. Physical Therapy can help build the body's tolerance to cancer treatments like chemotherapy and radiation through the use of exercise to increase heart rate, muscular strength, and range of motion. Lack of activity can lead to muscle weakness, decreased range of motion and decreased body function. 
Ways regular exercise may help you during cancer treatment 
• Keep or improve your physical abilities
• Better balance, lower risk of falls and broken bones
• Keep muscles from wasting due to inactivity
• Lower the risk of heart disease
• Lessen the risk of osteoporosis
• Improve blood flow to your legs and lower the risk of blood clots
• Make you less dependent on others for help with normal activities of daily living
• Improve your self-esteem
• Lower the risk of being anxious and depressed
• Lessen nausea
• Improve your ability to keep social contacts
• Fewer symptoms of fatigue
• Help you control your weight
• Improve your quality of life
Below are several differential diagnosis of thyroid cancer: 
Benign Thyroid nodules or cysts
Multiple Endocrine Neoplasia Type 2
Case Reports/ Case Studies
Bouillet B, Petit J, Tison L, Beynat C, Brunot S, Baudoin N. The first case report of diaphragmatic paralysis as a paraneoplastic syndrome of medullary thyroid carcinoma. Clinical Endocrinology [serial online]. July 2011;75(1):143-145. File:PDF2.pdf
Goatman C, Goldsmith P, Antonopoulos V, Ali B. Metastasis of Colorectal Adenocarcinoma to the Thyroid: A Case Report and Review of the Literature. Case Reports In Surgery [serial online]. January 2012;:1-3. File:PDF3.pdf
Kainuma K, Kitoh R, Yoshimura H, Usami S. The first report of bilateral retropharyngeal lymph node metastasis from papillary thyroid carcinoma and review of the literature. Acta Oto-Laryngologica [serial online]. December 2011;131(12):1341-1348.
Poggi M, Sorrentino F, Cianciulli P, et al. Malignancies in β-Thalassemia Patients: First Description of Two Cases of Thyroid Cancer and Review of the Literature. Hemoglobin [serial online]. August 2011;35(4):439-446. File:PDF4.pdf
add links to case studies here (case studies should be added on new pages using the case study template)
American Throid Association. http://www.thyroid.org/cancer-of-the-thyroid-gland/
National Cancer Institute. http://www.cancer.gov/cancertopics/types/thyroid
American Society of Clinical Oncology. http://www.cancer.net/cancer-types/thyroid-cancer
Thyroid Cancer Survivors' Association. http://www.thyca.org/
Thyroid Cancer Center. http://www.endocrineweb.com/conditions/thyroid-cancer
American Association of Clinical Endocrinologists. https://www.aace.com/
Recent Related Research (from Pubmed)
see tutorial on Adding PubMed Feed
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- Riverside. Thyroid Cancer.http://www.riversideonline.com/health_reference/Cancer/DS00492.cfm. Updated April 2, 2011. Accessed March 25, 2014.
- National Cancer Institute. Thyroid Cancer. http://www.cancer.gov/cancertopics/types/thyroid. Accessed March 6, 2014.
- American Society of Clinical Oncology. Thyroid Cancer. http://www.cancer.net/cancer-types/thyroid-cancer. Reviewed 7/2013. Accessed March 6, 2014.
- American Cancer Society. How is Thyroid Cancer Staged?http://www.cancer.org/cancer/thyroidcancer/detailedguide/thyroid-cancer-staging. Revised March 20, 2014. Accessed March 25, 2014.
- American Cancer Society. Thyroid Cancer. http://www.cancer.org/acs/groups/cid/documents/webcontent/003144-pdf.pdf. Updated March 20, 2014. Accessed March 25, 2014.
- American Thyroid Association. Thyroid Cancer. http://www.thyroid.org/cancer-of-the-thyroid-gland/. Accessed March 20, 2014.
- National Cancer Institute. Thyroid Cancer. http://www.cancer.gov/cancertopics/druginfo/thyroidcancer. Accessed March 20, 2014.
- National Cancer Institute. Metastatic Cancer. http://www.cancer.gov/cancertopics/factsheet/Sites-Types/metastatic. Updated March 28, 2013. Accessed March 25, 2014.
- Burke, D. Healthline. Metastatic Lung Cancer. http://www.healthline.com/health/metastatic-cancer-to-the-lung. Published June 25, 2012. Accessed March 6, 2014.
- Rice, S.C. Healthline. Liver Metastasis. http://www.healthline.com/health/liver-metastases. Accessed March 6, 2014.