Thyroid Cancer

Thyroid cancer occurs when cancerous cells form in the tissues of the thyroid, a butterfly-shaped gland located at the front of the neck. There are usually no early signs or symptoms. However, as the cancer grows, symptoms may include difficulty swallowing, swollen lymph nodes, and pain in the throat or neck. Treatment options for thyroid cancer include surgery, hormone therapy, chemotherapy, and radioactive iodine treatment.

 

What Is Thyroid Cancer?

Thyroid cancer is a disease in which cancer cells first develop in the tissues of the thyroid.
 

Understanding the Thyroid

The thyroid is a gland that is shaped like a butterfly and lies at the front of the neck, beneath the voice box (larynx).
 
A healthy thyroid:
 
  • Is a little larger than a quarter and cannot be felt through the skin
  • Is made up of two parts (lobes) that are separated by a thin section called the isthmus
  • Has two kinds of cells, follicular cells and C cells, which produce hormones.
 
Follicular cells make thyroid hormone, which affects heart rate, body temperature, and a person's energy levels. C cells make calcitonin, which is a hormone that helps control the level of calcium in the blood. A swollen lobe (goiter) might look or feel like a lump in the front of the neck and is usually the result of not getting enough iodine in the diet. Iodine is a substance that is found in shellfish and iodized salt.
 

Types of Thyroid Cancer

There are four main types of thyroid cancer that may be distinguished from each other based on how the cancer cells look under a microscope. These types include:
 
  • Papillary
  • Follicular
  • Medullary
  • Anaplastic.
 
If the cancer spreads outside of the thyroid, it is called metastatic thyroid cancer.
 
(Click Types of Thyroid Cancer for more information.)
 

What Causes It?

No one knows the exact cause or causes of thyroid cancer, and doctors can seldom explain why one person will get the disease and another person will not. However, it is clear that this disease is not contagious -- no one can "catch" thyroid cancer from another person. Research has shown that people with certain risk factors are more likely than others to develop it. A risk factor is anything that increases a person's chances of developing a disease. However, risk factors do not cause thyroid cancer.
 

Risk Factors for the Disease

Thyroid cancer risk factors include:
 
  • Exposure to high levels of radiation
  • Having a family history of the disease (or certain other health conditions, such as goiters)
  • Being female
  • Being over the age of 40
  • Being Caucasian
  • Not getting enough iodine in one's diet.
 
(Click Cause of Thyroid Cancer for more information about these risk factors.)
 

Symptoms of Thyroid Cancer

There are usually no early signs or symptoms of thyroid cancer. However, as the cancer grows, symptoms may include:
 
  • A lump or nodule in the front of the neck near the Adam's apple
  • Hoarseness or difficulty speaking in a normal voice
  • Swollen lymph nodes, especially in the neck
  • Difficulty swallowing or breathing
  • Pain in the throat or neck.
 
These symptoms are not sure signs of thyroid cancer. Other health problems can also cause these symptoms. People with possible symptoms of thyroid cancer should see a doctor as soon as possible -- only a doctor can diagnose and treat the problem.
 
(Click Thyroid Cancer Symptoms for more information.)
 

How Is It Diagnosed?

If a person has possible symptoms, the doctor will usually need to perform a physical exam, ask about the person's personal and family medical history, and recommend additional tests and procedures that examine the thyroid.
 
The exams and tests that are used to make a thyroid cancer diagnosis may include:
 
  • Blood tests
  • Ultrasound
  • Radionuclide scanning
  • Biopsy.
 
(Click Thyroid Cancer Diagnosis for more information.)
 

Thyroid Cancer Staging

If the doctor makes a thyroid cancer diagnosis, he or she will need to determine the stage, or extent, of the disease to plan treatment. Staging is an attempt to find out the size of the tumor, whether the disease has spread, and, if so, to what parts of the body.
 
The following tests and procedures may be used in thyroid cancer staging:
 
  • Ultrasound
  • Computed tomography (CT) scan
  • Magnetic resonance imaging (MRI)
  • Radionuclide scan (diagnostic I-131 whole body scan).
 
The staging will depend, in part, on the type of thyroid cancer a person has.
 
(Click Thyroid Cancer Staging for more information on the particular stages.)
 

Treatment for Thyroid Cancer

Thyroid cancer treatment options vary, based on:
 
  • The type of cancer
  • The stage of cancer (see Thyroid Cancer Staging)
  • The size of the nodule
  • Whether the cancer has spread
  • The person's age and general health.
 
In general, treatment options can include:
 
 
People with the disease should work with their healthcare provider to develop a treatment plan that meets their medical needs and personal values. Choosing the most appropriate treatment is a decision that ideally involves the affected person, the family, and the healthcare team.
 

Prognosis for Thyroid Cancer

The American Cancer Society (ACS) estimated that 30,180 Americans (7,590 men and 22,590 women) would be diagnosed with thyroid cancer in 2006. The ACS also estimated that 1,500 American men and women would die of thyroid cancer during 2006.
 
A thyroid cancer prognosis depends on:
 
  • The stage of the cancer
  • The type of cancer cells
  • How the cancer cells look under a microscope
  • The person's age and general health.
 
The prognosis is better for people who are younger than 40 years of age and who have cancer that has not spread beyond the thyroid.
 
(Click Thyroid Cancer Prognosis for more information.)
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Written by/reviewed by: Arthur Schoenstadt, MD
Last reviewed by: Arthur Schoenstadt, MD