Melanoma Risk

Melanoma is the least common of the different skin cancer types. However, left untreated, melanoma is also the most dangerous. Most skin cancer fatalities are due to melanoma. Although UVA rays and repeated sunburn have been linked to melanoma, they are not the only risk factors: ethnicity, presence of moles, and family history may increase your chances of developing the cancer.

Ethnicity, Skin Pigmentation and Melanin Levels

Caucasians are twenty times as likely to develop melanoma as people of African descent. This is because darker-skinned people have greater amounts of melanin present in their skin. Melanin helps protect the skin against ultraviolet light rays (UVA and UVB). A high level of melanin does not make a person immune to melanoma. No one is immune to skin cancer, but fair-skinned people are at greater risk.

Melanocytes, Melanin and Skin Pigmentation

The outer layer of the skin is known as the epidermis. Cells called melanocytes are responsible for skin pigmentation. These cells are found at the bottom of the epidermis and produce melanin, a substance that helps protect the body against sun damage. The ultraviolet rays in sunlight stimulate melanin production, which is why sun exposure leads to tanned, or darker, skin.

Differing levels of melanin are responsible for variations in skin color. However, the number of melanocytes in the body does not change with ethnicity: everyone has the same number of these melanin-producing cells. If melanocytes develop tumors, melanoma can be the result.

Other physical characteristics increase a person’s risk of developing skin cancer. In general, red or blonde hair increases the risk, as do blue eyes. People who are prone to freckles are also more at risk than others. Often several of these traits are seen together: people with red hair tend to have fair complexions, and are more likely to sunburn than others.

Moles and Skin Cancer

Having a high number of moles increases the risk of developing melanoma. Anyone with over fifty moles is considered to be at higher risk. Their shape and size may be more important than their numbers, however.

Moles

Moles are growths that occur when melanocytes crowd together. The medical term for a mole is a nevus (plural: nevi). Most often, moles are harmless, and perfectly normal. Everyone has moles: the average person typically has ten to forty moles. Moles are usually small and symmetrical, and may be either flat or elevated. They come in a variety of colors, including black, brown, tan and pink. Some moles are only slightly darker than the surrounding skin pigmentation.

If moles increase in size, change color (including turning red or white), bleed, or change shape, they should be evaluated by your doctor. Any change in the mole could be a sign that the group of melanocytes has become cancerous.

An irregular-looking mole, or dysplastic nevus, has a greater chance of becoming cancerous than a regular looking mole. One out of every ten people has a dysplastic nevus. Irregularities may include size or shape changes, color changes, or raised areas in previously flat moles. Dermatologists recommend monthly self-examinations to detect changes to moles. An unusual mole indicates an increased risk of melanoma, and should be checked by your doctor. Fifty percent of melanoma cases have been linked to dysplastic nevi, but other cases appear to have no connection to abnormal moles.

Mole Removal

Having a mole removed may seem to be a way to avoid melanoma, but studies suggest that mole removal will not benefit most people. Only one out of every 200,000 moles is diagnosed as cancerous in people under the age of forty.

Ultraviolet Light, Sunburn and Tanning Beds

Exposure to ultraviolet light, either from sunlight or tanning lamps and tanning beds, increases the risk of skin cancer. The two forms of ultraviolet light are UVA and UVB. Of the two, UVA penetrates deeper into the body. UVB has been linked to DNA mutations in skin cells.

Although a connection has been made between melanoma and exposure to UVA and UVB rays, the cancer can develop on parts of the body that are not exposed to the sun. Nevertheless, the disease has been linked to tanning beds, sun exposure and a history of childhood sunburn. Fair-skinned people living in the tropics also have higher incidence rates than average.

Sunscreen is one of the best ways to protect your skin from UV rays. Look for a sunscreen with an SPF (sun protection factor) of at least thirty. Apply the sunscreen generously to all exposed areas thirty minutes before going outdoors.

Sun Exposure and Tanning Beds

Melanoma has been linked to the stimulation of melanin production by ultraviolet rays. Such rays are found naturally in sunlight, but are also present in the artificial lights used in tanning beds. Overexposure to the sun or UV lights and tanning beds puts you at a greater risk of developing melanoma or other skin cancers.

Age, Gender and Family History

Fifty percent of all melanoma cases occur after the age of fifty. However, melanoma is also one of the most common cancers occurring before age thirty, so age only plays a partial role in susceptibility. Gender appears to play a larger role: men are more at risk than women. The lifetime risk of melanoma in women is one in 81. For men, lifetime incidence rates rise to one in 57. Men are more likely to develop tumors on the trunk — the area between the shoulders and the hips — or on the neck or the head. The lower legs and the arms are more common locations for women.

Although family history is not generally a factor, ten percent of people with melanoma have at least one close relative with this form of skin cancer.

Immunosuppression

People with suppressed immune systems are more susceptible to melanoma than others. This has been proven through studies on long-term cancer rates in organ transplant recipients. Transplant patients must use immunosuppression drugs to prevent organ rejection.

Resources

American Cancer Society. (nd). What are the risk factors for melanoma? Retrieved May 16, 2003, from www.cancer.org/docroot/cri/content/cri_2_4_2x_what_are_the_risk_factors_for_melanoma_50.asp.

Archives of Dermatology. (2003). Risk of moles becoming cancerous is low. Retrieved May 16, 2003, from www.chennaionline.com/health/homearticles/mole.asp.

National Cancer Institute. (2003). What you need to know about melanoma. Retrieved May 16, 2003, from www.cancer.gov/cancerinfo/wyntk/melanoma.

National Cancer Institute. (2003). What you need to know about moles and dysplastic nevi. Retrieved May 16, 2003, from www.cancer.gov/cancerinfo/wyntk/moles-and-dysplastic-nevi.