Understanding Thyroid Cancer

What is Thyroid Cancer?

Thyroid cancer is a malignant growth or tumor in the thyroid.  Thyroid cancer represents 3.8% of all new cancers in the United States1, and it is the most common cancer of the system of glands throughout the body that produce hormones, called the endocrine system. Thyroid cancer occurs in both men and women and can occur at any age.  However, thyroid cancer occurs almost three times more often in women than in men. Among both men and women, the number of new cases of thyroid cancer is increasing at a faster rate than any other type of cancer.1,2

Thyroid cancer represents 3.8% of all new cancer cases in the United States1

Estimated number of new cases of thyroid cancer per year in the United States3

There is a high treatment success rate for most types of thyroid cancer. When diagnosed and treated early, about 98% of patients with thyroid cancer survive for at least 5 years.1,2 Despite high treatment success, it is important to know that up to one-third of thyroid cancers can come back, sometimes even decades after the first treatment.4 For this reason, thyroid cancer requires long-term monitoring to make sure that the cancer has not come back, or if it has, to begin treatment right away.

Survival of people with well-differentiated thyroid cancer1

Different Types of Thyroid Cancer

Not all thyroid cancers are the same. There are four main types of thyroid cancer:2

  • Papillary
  • Follicular
  • Medullary
  • Anaplastic

Papillary and follicular cancers, often referred to as “well-differentiated” thyroid cancers (also referred to as WDTC), are the most common. Together, they account for about 90% of thyroid cancers.  Generally, the prognosis, or long-term outlook, for patients diagnosed with well-differentiated thyroid cancer is very good.  With regular checkups and long-term monitoring, the 5-year survival rate is nearly 98%.1 The other types of thyroid cancer, medullary and anaplastic, are much less common, and are more difficult to treat effectively.2

Prognosis and Outcomes for Patients with Thyroid Cancer

The prognosis for any given thyroid cancer patient depends on several factors, including the type of thyroid cancer, whether the disease has spread to other parts of the body, and the patient’s age at diagnosis.  Many cases of thyroid cancer can be found early and, in fact, most thyroid cancers are now found much earlier than in the past and can be treated successfully. Appropriate treatment and commitment to long-term monitoring is important to achieve the best outcome.2

Different types of thyroid cancer2,5


Average Age at Diagnosis

Prognosis at Time of Diagnosis









Variable, dependent on stage at diagnosis



Very poor

What Causes Thyroid Cancer?

It is not clear what causes thyroid cancer.  However, there are certain factors that may lead to a higher risk of getting thyroid cancer.  These include the following:2

  • Gender - thyroid cancers are more common in women
  • Age - women are most likely to get it in their 40s or 50s, while men are more likely to get it in their 60s or 70s
  • A diet low in iodine (this is rare in the US)
  • Radiation exposure - the risk is highest if exposure occurs in childhood
  • Family history - having a parent, brother, sister, or child with thyroid cancer increases your risk of thyroid cancer
  • Certain genetic conditions


  1. SEER. Thyroid cancer. 2015. http://seer.cancer.gov/statfacts/html/thyro.html. Accessed Nov 1, 2015.
  2. American Cancer Society.  Thyroid Cancer. 2015. http://www.cancer.org/acs/groups/cid/documents/webcontent/003144-pdf.pdf Accessed Jan 8, 2016.
  3. American Cancer Society: Facts and Figures: 2007-2015. http://www.cancer.org/research/cancerfactsstatistics/allcancerfactsfigures/index.  Accessed Jan 4, 2016.
  4. Al-Noury MK, Almuhayawi SM, Alghamdi KB, Al-Noury KI. Preoperative imaging
    modalities to predict the risk of regional nodal recurrence in well-differentiated thyroid cancers. Int Arch Otorhinolaryngol. 2015;19:116-120.
  5. Goodman, AL. Endocrineweb. Thyroid Cancer Guide - Incidence and Types of Thyroid Cancer. 2014. http://www.endocrineweb.com/guides/thyroid-cancer/indidence-types-thyroid-cancer. Accessed Jan 13, 2016.


Patient Organizations
Several organizations offer support and resources for thyroid cancer patients. Some of those are listed below for your reference.


Thyrogen® (thyrotropin alfa for injection) 0.9 mg/mL after reconstitution


There have been reports of events that led to death in patients who not had surgery to have their thyroid gland removed, and in patients with thyroid cancer cells that have spread to other parts of the body.

Patients over 65 years old with large amounts of leftover thyroid tissue after surgery, or with a history of heart disease, should discuss with their physicians the risks and benefits of Thyrogen.

Thyrogen can be administered in the hospital for patients at risk for complications from Thyrogen administration.

Since Thyrogen was first approved for use, there have been reports of central nervous system problems such as stroke in young women who have a higher chance of having a stroke, and weakness on one side of the body.

Patients should remain hydrated prior to treatment with Thyrogen.

Leftover thyroid tissue after surgery and cancer cells that have spread to other parts of the body can quickly grow and become painful after Thyrogen administration.

Patients with cancer cells near their windpipe, in their central nervous system, or in their lungs may need treatment with a glucocorticoid (a medication to help prevent an increase in the size of the cancer cells before using Thyrogen.)


In clinical studies, the most common side effects reported were nausea and headache.


Pregnant patients: Thyrogen should be given to a pregnant woman only if the doctor thinks there is a clear need for it.

Breastfeeding patients: It is not known whether Thyrogen can appear in human milk. Breastfeeding women should discuss the benefits and risks of Thyrogen with their physician.

Children: Safety and effectiveness in young patients (under the age of 18) have not been established.

Elderly: Studies do not show a difference in the safety and effectiveness of Thyrogen between adult patients less than 65 years and those over 65 years of age.

Patients with kidney disease: Thyrogen exits the body much slower in dialysis patients and can lead to longer high TSH levels.


Thyrogen is used to help identify thyroid disease by testing the blood for a hormone called thyroglobulin in the follow up of patients with a certain type of thyroid cancer known as well differentiated thyroid cancer. It is used with or without a radiology test using a form of iodine.

Limitations of Use:

The effect of Thyrogen on long term thyroid cancer outcomes has not been determined.

When Thyrogen is used to help detect thyroid cancer, there is still a chance all or parts of the cancer could be missed.

Thyrogen is also used to help patients prepare for treatment with a form of iodine to remove leftover thyroid tissue in patients who have had surgery to take out the entire thyroid gland for patients with well differentiated thyroid cancer who do not have signs of thyroid cancer which has spread to other parts of the body.

Limitations of Use:

In a study of people being prepared for treatment with a form of iodine after thyroid surgery, results were similar between those who received Thyrogen and those who stopped taking their thyroid hormone. Researchers do not know if results would be similar over a longer period of time.

See full Prescribing Information for more details.

You are encouraged to report negative side effects of prescription drugs to the FDA. Visit www.fda.gov/medwatch, or call 1-800-FDA-1088.