Source: National Cancer Institute Research, www.cancer.gov
Screening is looking for cancer before a person has any symptoms. This can help find cancer at an early stage. When abnormaltissue 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.
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 (top 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:
Basal cell carcinoma and squamous cell carcinoma are also called nonmelanoma skin cancer and are the most common forms of skin cancer. Most basal cell and squamous cell skin cancers can be cured.
Melanoma is more likely to spread to nearby tissues and other parts of the body and can be harder to cure. Melanoma is easier to cure if the tumor is found before it spreads to the dermis (inner layer of skin). Melanoma is less likely to cause death when it is found and treated early.
In the United States, the number of cases of nonmelanoma skin cancer seems to have increased in recent years. The number of cases of melanoma has increased over the last 30 years. Part of the reason for these increases may be that people are more aware of skin cancer. They are more likely to have skin exams and biopsies and to be diagnosed with skin cancer.
Over the past 20 years, the number of deaths from melanoma has decreased slightly among white men and women younger than 50 years. During that time, the number of deaths from melanoma has increased slightly among white men older than 50 years and stayed about the same among white women older than 50 years.
See the following PDQ summaries for more information about skin cancer:
Anything that increases your 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.
Being exposed to ultraviolet (UV) radiation and having skin that is sensitive to UV radiation are risk factors for skin cancer. UV radiation is the name for the invisible rays that are part of the energy that comes from the sun. Sunlamps and tanning beds also give off UV radiation.
Risk factors for nonmelanoma and melanoma cancers are not the same.
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 Web site.
If you find a worrisome change, you should report it to your 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 localexcision. 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.
Most melanomas in the skin can be seen by the naked eye. Usually, melanoma grows for a long time under the top layer of skin (the epidermis) but does not grow into the deeper layer of skin (the dermis). This allows time for skin cancer to be found early. Melanoma is easier to cure if it is found before it spreads.
Screening clinical trials are taking place in many parts of the country. Information about ongoing clinical trials is available from the NCI Web site.
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.
Screening may not improve your health or help you live longer if you have advancedskin cancer.
Some cancers never cause symptoms or become life-threatening, but if found by a screening test, the cancer may be treated. Treatments for cancer may have serious side effects.
Screening test results may appear to be normal even though 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 getting 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 (such as a biopsy), which also have risks.
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.
Talk to your doctor about your risk for skin cancer and your need for screening tests.