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A risk factor is anything that increases a person's chance of developing cancer. Although risk factors can influence the development of cancer, most do not directly cause cancer. Some people with several risk factors never develop cancer, while others with no known risk factors do. However, knowing your risk factors and talking about them to your doctor may help you make more informed lifestyle and health care choices.
The following factors may raise a person's risk of developing melanoma:
Sun exposure. Exposure to ultraviolet (UV) radiation from the sun can cause melanoma. Ultraviolet B (UVB) radiation from the sun appears more closely associated with melanoma, but newer information suggests that ultraviolet A (UVA) may also play a role in the development of melanoma, as well as basal and squamous cell skin cancers.
People who live in areas with bright sunlight year-round or at high altitudes have a higher risk of developing skin cancer, as do those who spend a lot of time outside during the midday hours. Risk of melanoma is higher in people whose skin has a tendency to burn rather than tan and who have had multiple, severe, blistering sunburns, particularly in childhood. Melanoma has also been linked to intermittent recreational exposure to UV, whether from the sun or from indoor tanning facilities.
Artificial tanning. People who use tanning beds, tanning parlors, or sun lamps have an increased risk of melanoma and other types of skin cancer. Recreational sun tanning should be avoided.
Moles. People with many moles or unusual moles called dysplastic nevi or atypical moles (flat, large moles that have irregular color and shape) have a higher risk of developing melanoma.
Fair skin. People with fair complexion, blond or red hair, blue eyes, and freckles are at increased risk for developing melanoma.
Family history. Approximately 10% of people with melanoma have a family history of melanoma. Therefore, it is recommended that close relatives (parents, brothers and sisters, and children) of a person with melanoma routinely have their skin examined. Changes in two genes (CDKN2A and CDK4)that may lead to melanoma have been identified. However, only a small number of families with melanoma have changes in these genes. It is likely that other genes and environmental factors also affect risk of melanoma. Learn more about the genetics of melanoma.
Personal history of skin cancer. People who have had one melanoma have an increased risk of developing additional new melanomas. People who have had basal cell or squamous cell skin cancer also have an increased risk of developing melanoma.
Race or ethnicity. Melanoma rates are more than 10 times higher in white people than black people; however, it is important to note that melanoma can occur in a person of any race or ethnicity. In fact, the rates of melanoma among Hispanics are rising.
Immune system. People who have weakened immune systems or use certain medications that suppress immune function have a higher risk of developing skin cancer.
Reducing exposure to UV radiation, particularly through reducing sun exposure, lowers the risk of melanoma. This is important for people of all ages and is especially important for people who have an increased risk of melanoma. Sun damage builds up over time. Steps to reduce sun exposure, avoid sunburn, and help prevent melanoma include:
- Limiting or avoiding sun exposure between 10:00 AM and 4:00 PM, as well as avoiding recreational sunbathing.
- Wearing sun-protective clothing, including a hat that shades the face, neck, and ears. Clothes made of fabric labeled with UPF (UV protection factor) may provide better protection. UV-protective sunglasses are also recommended.
- Using sunscreen with a sun protection factor (SPF) of 15 or higher throughout the year and reapplying it at least every two hours, especially after heavy perspiration or being in the water.
- Examining the skin regularly (including examinations by a health care professional and self-examinations). Learn more about the signs and symptoms of melanoma.
- Avoiding use of sun lamps, tanning beds, and tanning salons.
Learn more about protecting your skin from the sun.
It is important to note that limiting your sun exposure reduces your body's production of vitamin D. Therefore, people with limited sun exposure should talk with their doctor about how to include good sources of vitamin D in their diet, including the use of supplements.