Overview of Prevention

Prevention Purposes of this summary

Skin Cancer Prevention

Significance of skin cancer Skin cancer prevention

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Changes to This Summary (10/16/2008)
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Overview of Prevention

Prevention

Doctors cannot always explain why one person gets cancer and another does not. However, scientists have studied general patterns of cancer in the population to learn what things around us and what things we do in our lives may increase our chance of developing cancer.

Anything that increases a person’s chance of developing a disease is called a risk factor; anything that decreases a person’s chance of developing a disease is called a protective factor. Some of the risk factors for cancer can be avoided, but many cannot. For example, although you can choose to quit smoking, you cannot choose which genes you have inherited from your parents. Both smoking and inheriting specific genes could be considered risk factors for certain kinds of cancer, but only smoking can be avoided. Prevention means avoiding the risk factors and increasing the protective factors that can be controlled so that the chance of developing cancer decreases.

Although many risk factors can be avoided, it is important to keep in mind that avoiding risk factors does not guarantee that you will not get cancer. Also, most people with a particular risk factor for cancer do not actually get the disease. Some people are more sensitive than others are to factors that can cause cancer. Talk to your doctor about methods of preventing cancer that might be effective for you.

The purposes of this summary on skin cancer prevention are to:

• Give information on skin cancer and how often it occurs.
• Describe skin cancer prevention methods.
• Give current facts about which people or groups of people would most likely be helped by following skin cancer prevention methods.

You can talk to your doctor or health care professional about cancer prevention methods and whether they would be likely to help you.

Skin Cancer Prevention

The skin protects the body against heat and light, injury, and infection. It also helps regulate body temperature, stores water and fat, and produces vitamin D. The skin is the body’s largest organ and is made up of two main layers: the outer epidermis and the inner dermis.

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Anatomy of the skin, showing the epidermis, dermis, and subcutaneous tissue.

There are 3 types of skin cancer: basal cell carcinoma, squamous cell carcinoma (together referred to as nonmelanoma skin cancer), and melanoma. The outer layer of the skin is made up of squamous cells. Basal cells are found below the squamous cells. Melanocytes are in the deepest layer of epidermis. Melanoma develops from melanocytes.

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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 cancer is the most commonly occurring cancer in the United States. Basal cell carcinoma and squamous cell carcinoma (nonmelanoma skin cancer) are the most common forms of skin cancer, but are easier to cure than melanoma. The number of new cases of skin cancer appears to be increasing each year. The number of deaths due to skin cancer, however, is fairly small.

Nonmelanoma Skin Cancer (Basal Cell Carcinoma and Squamous Cell Carcinoma): Studies have suggested that reducing exposure to ultraviolet (UV) radiation decreases the incidence of nonmelanoma skin cancer. Ultraviolet radiation is a stream of invisible high-energy rays coming from the sun. Artificial sources such as tanning booths and sunlamps also produce ultraviolet radiation.

Sun exposure can be reduced by changing patterns of outdoor activities to reduce time of exposure to high-intensity UV radiation (the sun is strongest from 11 am to 3 pm), wearing protective clothing (such as long sleeves and hats) when exposed to sunlight, and by using adequate amounts of sufficiently protective sunscreen.

It is not known whether using sunscreen lowers the risk of either squamous cell carcinoma or basal cell carcinoma.

People whose skin tans poorly or burns easily after sun exposure are particularly susceptible to nonmelanoma skin cancer. These people in particular may benefit by following prevention methods for nonmelanoma skin cancer.

Melanoma: It is not known if avoiding sunburns reduces a person's chance of developing melanoma skin cancer.

Sunburn can be avoided by changing patterns of outdoor activities to reduce time of exposure to high-intensity UV radiation (the sun is strongest from 11 am to 3 pm), wearing protective clothing (such as long sleeves and hats) when exposed to sunlight, and using sunscreen.

Sunscreen is not a substitute for avoidance of sun exposure.

People whose skin tans poorly or who have a large number of abnormal moles may have an increased risk of developing melanoma skin cancer. These people in particular may benefit by following prevention methods for melanoma.

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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.

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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 ². 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.

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A clinical trial is a study to answer a scientific question, such as whether a certain drug or nutrient can prevent cancer. 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 prevention clinical trials, information is collected about the effects of a new prevention 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 ⁵. 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.

Glossary Terms

Not normal. An abnormal lesion or growth may be cancerous, premalignant (likely to become cancer), or benign.

A small, round cell found in the lower part (or base) of the epidermis, the outer layer of the skin.

A type of skin cancer that arises from the basal cells, small round cells found in the lower part (or base) of the epidermis, the outer layer of the skin.

A term for diseases in which abnormal cells divide without control. Cancer cells can invade nearby tissues and can spread to other parts of the body through the blood and lymph systems. There are several main types of cancer. Carcinoma is cancer that begins in the skin or in tissues that line or cover internal organs. Sarcoma is cancer that begins in bone, cartilage, fat, muscle, blood vessels, or other connective or supportive tissue. Leukemia is cancer that starts in blood-forming tissue such as the bone marrow, and causes large numbers of abnormal blood cells to be produced and enter the blood. Lymphoma and multiple myeloma are cancers that begin in the cells of the immune system. Central nervous system cancers are cancers that begin in the tissues of the brain and spinal cord.

To heal or restore health; a treatment to restore health.

The lower or inner layer of the two main layers of tissue that make up the skin.

The upper or outer layer of the two main layers of tissue that make up the skin.

The functional and physical unit of heredity passed from parent to offspring. Genes are pieces of DNA, and most genes contain the information for making a specific protein.

The number of new cases of a disease diagnosed each year.

Invasion and multiplication of germs in the body. Infections can occur in any part of the body and can spread throughout the body. The germs may be bacteria, viruses, yeast, or fungi. They can cause a fever and other problems, depending on where the infection occurs. When the body’s natural defense system is strong, it can often fight the germs and prevent infection. Some cancer treatments can weaken the natural defense system.

Transmitted through genes that have been passed from parents to their offspring (children).

A cell in the skin and eyes that produces and contains the pigment called melanin.

A form of cancer that begins in melanocytes (cells that make the pigment melanin). It may begin in a mole (skin melanoma), but can also begin in other pigmented tissues, such as in the eye or in the intestines.

A benign (noncancerous) growth on the skin that is formed by a cluster of melanocytes (cells that make a substance called melanin, which gives color to skin and eyes). A mole is usually dark and may be raised from the skin. Also called nevus.

Skin cancer that forms in basal cells or squamous cells but not in melanocytes (pigment-producing cells of the skin).

A part of the body that performs a specific function. For example, the heart is an organ.

PDQ is an online database developed and maintained by the National Cancer Institute. Designed to make the most current, credible, and accurate cancer information available to health professionals and the public, PDQ contains peer-reviewed summaries on cancer treatment, screening, prevention, genetics, complementary and alternative medicine, and supportive care; a registry of cancer clinical trials from around the world; and directories of physicians, professionals who provide genetics services, and organizations that provide cancer care. Most of this information, and more specific information about PDQ, can be found on the NCI's Web site at http://www.cancer.gov/cancertopics/pdq. Also called Physician Data Query.

Something that may increase the chance of developing a disease. Some examples of risk factors for cancer include age, a family history of certain cancers, use of tobacco products, certain eating habits, obesity, lack of exercise, exposure to radiation or other cancer-causing agents, and certain genetic changes.

Flat cell that looks like a fish scale under a microscope. These cells cover inside and outside surfaces of the body. They are found in the tissues that form the surface of the skin, the lining of the hollow organs of the body (such as the bladder, kidney, and uterus), and the passages of the respiratory and digestive tracts.

Cancer that begins in squamous cells, which are thin, flat cells that look like fish scales. Squamous cells are found in the tissue that forms the surface of the skin, the lining of the hollow organs of the body, and the passages of the respiratory and digestive tracts. Also called epidermoid carcinoma.

A substance that helps protect the skin from the sun's harmful rays. Sunscreens reflect, absorb, and scatter both ultraviolet A and B radiation to provide protection against both types of radiation. Using lotions, creams, or gels that contain sunscreens can help protect the skin from premature aging and damage that may lead to skin cancer.

Invisible rays that are part of the energy that comes from the sun. UV radiation also comes from sun lamps and tanning beds. UV radiation can damage the skin and cause melanoma and other types of skin cancer. UV radiation that reaches the Earth's surface is made up of two types of rays, called UVA and UVB rays. UVB rays are more likely than UVA rays to cause sunburn, but UVA rays pass deeper into the skin. Scientists have long thought that UVB radiation can cause melanoma and other types of skin cancer. They now think that UVA radiation also may add to skin damage that can lead to skin cancer and cause premature aging. For this reason, skin specialists recommend that people use sunscreens that reflect, absorb, or scatter both kinds of UV radiation. Also called UV radiation.

A nutrient that helps the body use calcium and phosphorus and make strong bones and teeth. It is found in fatty fish, eggs, and dairy products. The skin can also make vitamin D when exposed to sunshine. Not getting enough vitamin D can cause a bone disease called rickets. Vitamin D is being studied in the prevention and treatment of some types of cancer. Also called cholecalciferol.