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Table of Contents What is screening?
General Information About Skin Cancer
Skin Cancer Screening
Risks of Skin Cancer Screening
Get More Information From NCI
Changes to This Summary (10/16/2008)
Questions or Comments About This Summary
About PDQ
What is screening?
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 diagnostic tests.
Refer to the following PDQ summaries for more information about prevention, diagnosis, and treatment of skin cancer:
Back to Top General Information About Skin Cancer
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Skin cancer is a disease in which malignant (cancer) cells form
in the tissues of the skin.
The skin is the body's largest organ. It protects against heat,
sunlight, injury, and infection. Skin also helps control body temperature and stores water, fat, and vitamin D. The skin has several layers, but the two main layers are the epidermis (upper or outer layer) and the dermis (lower or inner layer). Skin cancer begins in the epidermis, which is made up of three kinds of cells:
- Squamous cells: Thin, flat cells that form the top layer of the epidermis.
- Basal cells: Round cells under the squamous cells.
- Melanocytes: Found
in the lower part of the epidermis, these cells make melanin, the pigment that gives skin its natural color. When skin is exposed to the sun, melanocytes
make more pigment, causing the skin to tan, or darken.
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| Anatomy of the skin, showing the epidermis, dermis, and subcutaneous tissue. |
Skin cancer is the most common cancer in the United
States.
The three most common types of skin cancer are basal cell carcinoma, squamous cell carcinoma, and melanoma. Basal cell carcinoma is the most common and melanoma is the least common skin cancer.
Most basal cell and squamous cell
skin cancers can be cured, but people with these types of cancer have a higher risk for developing other skin cancers. Melanoma causes about three fourths of
skin cancer deaths in the United States and is the focus of this screening summary.
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| Anatomy of the skin, showing the epidermis, dermis, and subcutaneous tissue. Melanocytes are in the layer of basal cells at the deepest part of the epidermis. |
Skin color and exposure to sunlight can affect the risk of developing melanoma.
Anything that increases your chance of getting a disease
is called a risk factor. Risk factors for melanoma include the following:
- Having a fair complexion (blond or red hair, fair skin, freckles, blue eyes).
- Being exposed to natural sunlight or ultraviolet light (such as tanning booths) over long periods of time.
- Being white and older than 20 years.
- Having several large or many small moles.
- Having a family history of
unusual moles (atypical nevus syndrome).
- Having a family or personal history of melanoma.
The best defense against skin cancer is protection from sunlight and ultraviolet light. Refer to the PDQ summary on Prevention of Skin Cancer for more information.
Back to Top Skin Cancer Screening
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Tests are used to screen for different types of cancer.
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 risks 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, finding and treating the disease at an early stage may result in a better chance of recovery.
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 NCI Cancer.gov Web site.
Skin examinations are commonly used to screen for melanoma.
Regular examination of the skin by both you and your doctor increases the chance of finding melanoma early. Most melanomas that appear in the skin can be seen by the
naked eye. Usually, there is a long period of time when the tumor grows beneath
the top layer of skin but does not grow into the deeper skin layers. This period
of slow growth allows time for skin cancer to be found early. Skin cancer may be cured if the
tumor is found before it spreads deeper. Monthly self-examination of the skin
may help find changes that should be reported to a doctor. Regular skin checks by a doctor are important for people who have
already had skin cancer.
If an area on the skin looks abnormal, a biopsy is usually done. The doctor will remove as much of the suspicious tissue as possible with a local excision. A pathologist then looks at the
tissue under a microscope to check
for cancer cells. Because it is sometimes difficult to tell if a skin growth is benign (not cancer) or malignant (cancer), you may want to have the biopsy sample checked by a second pathologist.
Other screening tests are being studied in clinical trials.
Screening clinical trials are taking place in many parts of the country. Information about ongoing clinical trials is available from the NCI Cancer.gov Web site.
Back to Top Risks of Skin Cancer Screening
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Screening tests have risks.
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.
The risks of melanoma screening tests include the following:
Finding melanoma may not improve health or help a person live
longer.
Screening
may not improve your health or help you live longer if you have advanced melanoma or if it has already spread to
other places in your body.
Some cancers never cause symptoms or become life-threatening, but if found by a screening
test, the cancer may be treated. It is not known if treatment of these cancers would help you live longer than if no treatment were given, and treatments for cancer may have serious side effects.
False-negative test results can occur.
Screening test results may appear to be normal even though melanoma 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.
False-positive test results can occur.
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 (such as
a biopsy), which also have risks.
A biopsy may cause scarring.
When a skin biopsy is done, the doctor will try to leave the
smallest scar possible, but there is a risk of scarring and infection.
Your doctor can advise you about your risk for skin cancer and your need for screening tests.
Back to Top Get More Information From NCI
Call 1-800-4-CANCER
For more information, U.S. residents may call the National Cancer Institute's (NCI's) Cancer Information Service toll-free at 1-800-4-CANCER (1-800-422-6237) Monday through Friday from 9:00 a.m. to 4:30 p.m. Deaf and hard-of-hearing callers with TTY equipment may call 1-800-332-8615. The call is free and a trained Cancer Information Specialist is available to answer your questions.
Chat online
The NCI's LiveHelp® online chat service provides Internet users with the ability to chat online with an Information Specialist. The service is available from 9:00 a.m. to 11:00 p.m. Eastern time, Monday through Friday. Information Specialists can help Internet users find information on NCI Web sites and answer questions about cancer.
Write to us
For more information from the NCI, please write to this address:
- NCI Public Inquiries Office
- Suite 3036A
- 6116 Executive Boulevard, MSC8322
- Bethesda, MD 20892-8322
Search the NCI Web site
The NCI Web site provides online access to information on cancer, clinical trials, and other Web sites and organizations that offer support and resources for cancer patients and their families. For a quick search, use our “Best Bets” search box in the upper right hand corner of each Web page. The results that are most closely related to your search term will be listed as Best Bets at the top of the list of search results.
There are also many other places to get materials and information about cancer treatment and services. Hospitals in your area may have information about local and regional agencies that have information on finances, getting to and from treatment, receiving care at home, and dealing with problems related to cancer treatment.
Find Publications
The NCI has booklets and other materials for patients, health professionals, and the public. These publications discuss types of cancer, methods of cancer treatment, coping with cancer, and clinical trials. Some publications provide information on tests for cancer, cancer causes and prevention, cancer statistics, and NCI research activities. NCI materials on these and other topics may be ordered online or printed directly from the NCI Publications Locator. These materials can also be ordered by telephone from the Cancer Information Service toll-free at 1-800-4-CANCER (1-800-422-6237), TTY at 1-800-332-8615.
Back to Top Changes to This Summary (10/16/2008)
The PDQ cancer information summaries are reviewed regularly and updated as new information becomes available. This section describes the latest changes made to this summary as of the date above.
Images were added to this summary.
Back to Top Questions or Comments About This Summary
If you have questions or comments about this summary, please send them to Cancer.gov through the Web site’s Contact Form. We can respond only to email messages written in English.
Back to Top About PDQ
PDQ is a comprehensive cancer database available on NCI's Web site.
PDQ is the National Cancer Institute's (NCI's) comprehensive cancer information database. Most of the information contained in PDQ is available online at NCI's Web site. PDQ is provided as a service of the NCI. The NCI is part of the National Institutes of Health, the federal government's focal point for biomedical research.
PDQ contains cancer information summaries.
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 are available in two versions. The health professional versions provide detailed information written in technical language. The patient versions are written in easy-to-understand, nontechnical language. Both versions provide current and accurate cancer information.
The PDQ cancer information summaries are developed by cancer experts and reviewed regularly.
Editorial Boards made up of experts in oncology and related specialties are responsible for writing and maintaining the cancer information summaries. The summaries are reviewed regularly and changes are made as new information becomes available. The date on each summary ("Date Last Modified") indicates the time of the most recent change.
PDQ also contains information on clinical trials.
A clinical trial is a study to answer a scientific question, such as whether a method of finding cancer earlier can help people to live longer. Trials are based on past studies and what has been learned in the laboratory. Each trial answers certain scientific questions in order to find new and better ways to help cancer patients and those who are at risk for cancer. During screening clinical trials, information is collected about the effects of a new screening method and how well it works. If a clinical trial shows that a new method is better than one currently being used, the new method may become "standard." People who are at high risk for a certain type of cancer may want to think about taking part in a clinical trial.
Listings of clinical trials are included in PDQ and are available online at NCI's Web site. Descriptions of the trials are available in health professional and patient versions. Many cancer doctors who take part in clinical trials are also listed in PDQ. For more information, call the Cancer Information Service 1-800-4-CANCER (1-800-422-6237); TTY at 1-800-332-8615.
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