Screening is looking for cancer before a person has any symptoms.
This can help find cancer at an early stage. When abnormal tissue or cancer is found early, it may be easier to treat.
By the time symptoms appear, cancer may have begun to spread.
Scientists are trying to better understand which people are
more likely to get certain types of cancer. They also study the
things we do and the things around us to see if they cause cancer.
This information helps doctors recommend who should be screened
for cancer, which screening tests should be used, and how often
the tests should be done.
It is important to remember that your doctor does not necessarily
think you have cancer if he or she suggests a screening test.
Screening tests are given when you have no cancer symptoms.
If a screening test result is abnormal, you may need to have more
tests done to find out if you have cancer. These are called
The thyroid is a gland at the base of the throat near the trachea (windpipe). It is shaped like a butterfly, with a right lobe and a left lobe. The isthmus, a thin piece of tissue, connects the two lobes. A healthy thyroid is about the size of a walnut. It usually cannot be felt through the skin.
The thyroid uses iodine, a mineral found in some foods and in iodized salt, to help make several hormones. Thyroid hormones do the following:
See the PDQ summary on Thyroid Cancer Treatment (Adult) for more information about
Thyroid cancer is most often diagnosed in men and women aged 45 to 54 years. It is the most commonly diagnosed cancer in women aged 20 to 34 years. Women are about three times more likely than men to have thyroid cancer.
The number of people diagnosed with thyroid cancer in the United States has been rising for at least 40 years, but the number of deaths from thyroid cancer has stayed the same or decreased slightly. Most cases of thyroid cancer respond to treatment and are usually cured.
Anything that increases the chance of getting a disease is
called a risk factor. Having a risk factor does not mean
that you will get cancer; not having risk factors doesn't
mean that you will not get cancer. People who think they may
be at risk should discuss this with their doctor.
Risk factors for thyroid cancer include the following:
Some screening tests are used because they have been shown to
be helpful both in finding cancers early and in decreasing the
chance of dying from these cancers. Other tests are used because
they have been shown to find cancer in some people; however, it
has not been proven in clinical trials that use of these tests
will decrease the risk of dying from cancer.
Scientists study screening tests to find those with the fewest
harms and most benefits. Cancer screening trials also are meant
to show whether early detection (finding cancer before it causes
symptoms) decreases a person's chance of dying from the disease.
For some types of cancer, the chance of recovery is better if
the disease is found and treated at an early stage.
Clinical trials that study cancer screening methods are taking
place in many parts of the country. Information about ongoing
clinical trials is available from the
There is no standard or routine screening test used for early detection of thyroid cancer. Thyroid cancer that does not cause symptoms may be found during the following:
Studies have shown that screening for thyroid cancer does not decrease the chance of dying from the disease. No randomized clinical trials have been done in the United States to find out if a neck exam, ultrasound, or other screening test decreases the risk of dying from thyroid cancer.
Decisions about screening tests can be difficult. Not all
screening tests are helpful and most have risks. Before having
any screening test, you may want to discuss the test with your
doctor. It is important to know the risks of the test and whether
it has been proven to reduce the risk of dying from cancer.
When a screening test result leads to the diagnosis and treatment of a disease that may never have caused symptoms or become life-threatening, it is called overdiagnosis. Diagnostic tests (such as a fine-needle aspiration biopsy) and cancer treatments (such as surgery and radioactive iodine therapy) can have serious risks, including physical and emotional problems.
Screening test results may appear to be normal even though thyroid
cancer is present. A person who receives a false-negative test result
(one that shows there is no cancer when there really is) may
delay seeking medical care even if there are symptoms.
Screening test results may appear to be abnormal even though
no cancer is present. A false-positive test result (one that
shows there is cancer when there really isn't) can cause anxiety
and is usually followed by more tests and procedures (such
as a fine-needle aspiration biopsy), which also have risks.
Physician Data Query (PDQ) is the National Cancer Institute's (NCI's) comprehensive cancer information database. The PDQ database contains summaries of the latest published information on cancer prevention, detection, genetics, treatment, supportive care, and complementary and alternative medicine. Most summaries come in two versions. The health professional versions have detailed information written in technical language. The patient versions are written in easy-to-understand, nontechnical language. Both versions have cancer information that is accurate and up to date and most versions are also available in Spanish.
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This PDQ cancer information summary has current information about the screening of thyroid cancer. It is meant to inform and help patients, families, and caregivers. It does not give formal guidelines or recommendations for making decisions about health care.
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The information in this patient summary was taken from the health professional version, which is reviewed regularly and updated as needed, by the PDQ Screening and Prevention Editorial Board.
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The best way to cite this PDQ summary is:
PDQ® Screening and Prevention Editorial Board. PDQ Thyroid Cancer Screening. Bethesda, MD: National Cancer Institute. Updated . Available at: https://www.cancer.gov/types/thyroid/patient/thyroid-screening-pdq. Accessed .
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