Some people are at higher risk of developing melanoma skin cancer than others. Scientists have identified several factors that influence an individual's melanoma risk.
Exposure to Ultraviolet Light
Exposure to ultraviolet (UV) light, from the sun or other sources, such as indoor tanning, is an important risk factor for melanoma. As with other skin cancers, long-term or frequent exposure to UV light increases melanoma risk. However, melanoma risk can also increase in response to occasional intense exposure to UV rays. In particular, repeated sunburns in childhood have been identified as a factor that increases the risk of melanoma. Some scientific evidence indicates that melanomas that occur in areas only occasionally exposed to UV rays, such as the trunk, legs, and arms, may be different in nature from those that occur in areas that receive more constant sun exposure, such as the face and neck.
People who have many moles, especially atypical-looking (dysplastic) moles, have an increased risk of developing melanoma. Experts estimate that people with dysplastic moles have a 6 to 10 percent risk of having a melanoma at some time in their lives. Dermatologists recommend that people with many moles or with atypical moles should have regular skin examinations because melanoma can be treated most effectively if it is detected early.
As is true for most types of cancer, the risk of melanoma increases with age. However, this tendency is not as pronounced for melanoma as for many other types of cancer. Melanoma sometimes occurs in people under the age of 30. Therefore, anyone, of any age, who notices suspicious changes in a mole should see a doctor.
Melanoma occurs more often in men than in women.
People with the rare inherited disease xeroderma pigmentosum have a high risk of melanoma because they cannot properly repair damage to DNA caused by sunlight.
People with a family history of melanoma are at increased risk of developing melanoma themselves. Among patients with melanoma, 5 to 10 percent have a close relative, such as a parent, sibling, or grandparent, who also had melanoma.
As is also true for other types of skin cancer, people with light-colored skin, hair, and eyes (especially those who tan poorly or not at all and who tend to form freckles) have a higher risk of melanoma than people with darker pigmentation do. However, melanoma can develop in people of all racial and ethnic groups, although it is much less common among dark-skinned people than light-skinned ones.
Suppression of the immune system, by drugs or disease, increases the risk of melanoma as well as other types of cancer because it limits the body's ability to recognize and eliminate cancer cells.
Among people who have had one melanoma, 5 to 10 percent will develop another one on a different part of their bodies. Therefore, patients who have been treated for melanoma should be careful to follow their doctors' screening and prevention recommendations.