According to the American Cancer Society the lifetime risk of getting melanoma is about 2% (1 in 50) for whites, 0.1% (1 in 1,000) for blacks, and 0.5% (1 in 200) for Hispanics. The number of melanoma cases has been increasing over the past 30 years.
Survival rates have been improving, however, and the increase in melanomas has occurred mainly with less aggressive forms of the disease. Some experts believe this is due to earlier diagnosis and increased awareness of the disease, resulting from effective public health programs.
The following factors increase your risk for skin cancer:
- Age over 40
- Being male
- Fair skin
- Too much exposure to sunlight and ultraviolet radiation, including indoor tanning
- High mole count, particularly on the arms
- Personal history of skin cancer
- Family history of skin cancer
- Certain chronic or severe skin problems
- Certain medical conditions or treatments that affect your immune system
- Exposure to chemicals or radiation
- Taking TNF-alpha blockers to treat rheumatoid arthritis or other illnesses
Age and Gender
Aging may weaken the body's ability to fend off cancers, including melanomas. As a person ages, they lose Langerhans cells that help fight off early skin cancers, possibly setting the stage for skin cancers in later life.
Melanoma in Adults. Melanoma is most common in people over 40, although it also can affect young and middle-aged people. The average age at diagnosis is 57 years. Men are more likely to have invasive and fatal melanoma than women, although some research suggests that the higher rates are only because men fail to get suspicious skin changes diagnosed before they become dangerous. The rate in women levels off somewhat after age 50; researchers think menopause could have some sort of protective effect.
Melanoma in Children. Melanoma is rare in children under age 10. Among children ages 10 - 14 the incidence is only 0.3 per 100,000 children. Between ages 14 - 19, it is still very rare, with only 1.3 cases per 100,000 children. Parents should not be too alarmed by every minor skin imperfection in their children. However, melanoma is as serious in children as it is in adults, and early detection is still critical. It is also noteworthy that the incidence of melanoma in children and adolescents has been steadily increasing, by about 2% per year.
Nonmelanoma skin cancers are rare in children and young adults, but they begin to increase significantly in middle age and older.
Sunlight and Ultraviolet Radiation Exposure
Skin cancer is associated with both the length and intensity of sun exposure. The risk of melanoma increases with excessive sun exposure during the first 10 - 18 years of life. Sunburns are also dangerous; having five or more sunburns doubles the risk of developing skin cancer. The cancer typically arises many years later.
Tanning Devices. Tanning beds and sun lamps increase the risk for developing melanoma, and the risk increases with frequency and length of use. Women in their 20s, as well as blondes and redheads, are especially at risk.
Phototherapy and Photochemotherapy with PUVA. There is some evidence that long-term treatment for psoriasis and other skin conditions using UVA radiation (PUVA) may increase the risk for melanoma.
Ethnic Groups and Complexion. People with light skin; blue, gray, or green eyes; red or blond hair; and lots of freckles are at highest risk for developing all types of skin cancers. The risk increases for those who easily sunburn and rarely tan, particularly if they live close to the equator where sunlight is most intense. However, people with darker complexions are not immune.
A classification system has been created for skin phototypes (SPTs) based on the sensitivity to sunlight. It ranges from SPT I (lightest skin plus other factors) to IV (darkest skin). People with skin types I and II are at highest risk for photoaging skin diseases, including cancer. It should be noted, however, that premature aging from sunlight can affect people of all skin shades.
Tanning and Sunburn Risk
Tanning and Burning Risk
Always burns, never tans, sensitive to sun exposure.
Burns easily, tans minimally.
Burns moderately, tans gradually to light brown.
Burns minimally, always tans well to moderately brown.
Rarely burns, tans profusely to dark.
Never burns, deeply pigmented, least sensitive.
Geography plays a role in skin cancer risk, primarily with regard to the intensity and length of sun exposure in certain locations. Studies show an increased incidence of melanomas in populations that previously had a lower incidence, but then migrated to Australia.
People with certain genetic characteristics, such as blue or green eyes, or blonde or red hair, have an increased risk of skin cancers.
Patients diagnosed with melanoma, and who have a family history of melanoma or nevi, are considered to be at increased risk for more invasive cancers. A number of genetic factors are being investigated for their role in melanomas, including inherited genes and genetic defects that are acquired through the environment (particularly sunlight).
Your genetic makeup, and whether or not certain genes mutate in your body can increase your risk of developing melanoma and other skin cancers.
A genetic mutation in a gene called BRAF occurs in approximately 50% of patients with advanced melanoma.
Personal or Family History of Skin Cancer
Melanoma. Individuals who have been diagnosed with melanoma are at increased risk for a second primary melanoma. That risk may be as high as 5%, and is higher in older men and in those whose first melanoma was on the upper body and face.
People with family members who have or had melanoma have approximately a twofold risk of developing melanoma as those without a family history, and should be examined on a regular basis.
Nonmelanoma Skin Cancers. The evidence for an increased risk of nonmelanoma skin cancers with a family history of such cancers is increasing, but it is still weaker than the evidence for a familial connection to the risk of melanoma.
Skin Conditions that Increase Skin Cancer Risk
Moles (Nevi) and Other Dark Blemishes. Certain moles and dark blemishes increase the risk for skin cancer. Any mole (nevus) or other blemish that seems new, changing, or unusual in any way should be evaluated by a health care professional as an existing mole can become cancerous. Although 80% of melanoma cases develop from brand new lesions or moles, your risk of developing the condition increases if you have the tendency to develop moles.
Some specific moles or dark blemishes that are risk factors for melanoma include:
- Freckles. Freckles typically appear in children on sun-exposed areas and are usually evenly brown or tan. The more freckles a person develops as a child, the greater the risk for melanoma in adulthood.
- Dysplastic (or Atypical) Nevi. About 30% of the population has moles called dysplastic nevi, or atypical moles. They are larger than ordinary moles (most are 5 mm across, about the size of a pencil eraser, or larger), have irregular borders, and are various shades or colors. Individuals who have dysplastic nevi plus a family history of melanoma (a syndrome known as FAMM) are at a high risk for developing melanoma at an early age (younger than 40). The risk for those with atypical moles and no family history of melanoma is less clear.
- Large birthmarks (giant congenital nevi). Very large birthmarks more than 8 inches across are major risk factors for melanoma. In such cases, cancer usually appears by age 10. Medium-sized congenital nevi do not appear to increase the risk for melanoma. Whenever possible, very large birthmarks should be removed during infancy. Experts disagree, however, about whether small birthmarks need to be removed. Parents should watch any birthmark for changes.
The more moles a person has, the higher the risk that one of those moles will become cancerous, although the danger is still very small. The risk is higher, however, with atypical moles.
Some skin blemishes can look like -- but are not -- melanoma. Noncancerous moles typically have the following characteristics:
- They generally remain small with clearly defined, regular borders, and uniform color. Some have a regular spotted or net-like pattern of pigmentation, however, and may even resemble early melanoma.
- They typically first appear during childhood, puberty, or young adulthood. They may naturally grow, darken, or increase in number at certain times of life, such as adolescence or pregnancy.
Examples of moles or blemishes that may resemble skin cancer include:
Blue nevus. A benign mole that may easily be mistaken for melanoma. It is a blue-black, smooth, raised nodule and commonly occurs on the buttocks, hands, or feet.
Liver Spots. Liver spots are usually evenly brown or tan spots caused by the sun. They are universal signs of aging. Occurring most noticeably on the hands and face, these harmless blemishes tend to enlarge and darken over time.
Spindle Cell (Spitz) Nevus. Children may develop a benign lesion called a spindle cell (or Spitz) nevus. The mole is firm, raised, and pink or reddish-brown. It may be smooth or scaly and usually appears on the face, particularly on the cheeks. It is not harmful, but it may be difficult to tell apart from a melanoma, even for experts.
Diseases and Treatments that Increase Skin Cancer Risk
Non-Hodgkin's Lymphoma. Survivors of either non-Hodgkin's lymphoma or melanoma face a higher risk for the other cancer. These diseases may have common causes, such as exposure to UV radiation or shared genetic factors.
Human papillomavirus (HPV). Genital warts (caused by human papillomavirus, or HPV) may also increase the risk of squamous cell cancer in the genital and anal areas and around fingernails.
Endometriosis. The condition in which cells that line the uterus also grow in other parts of the abdomen may be linked to a higher risk of melanoma. In one large study, women with a history of endometriosis had a 60% increased risk of developing melanoma. Those with uterine fibroids (benign tumors in the uterus) were also at increased risk.
Skin cancer risk is increased in people whose immune systems are suppressed because of certain medications, organ transplantation, or medical conditions such as AIDS. Melanoma has also developed in patients who received solid organ transplants from donors who had the disease.
Immune-suppressing drugs used to treat autoimmune disorders may also increase the risk of skin cancer. For example, patients who take TNF-alpha blockers to treat rheumatoid arthritis and other autoimmune diseases carry an increased risk for both melanoma and nonmelanoma skin cancers. Potential skin cancer risks have been associated with the eczema drugs pimecrolimus (Elidel) and tacrolimus (Protopic) in a small number of people. It is not known for sure whether these drugs, when used topically on the skin, actually cause cancer.
Occupational Radiation and Chemical Exposure
Occupational exposure to radiation and some chemicals (vinyl chloride, polychlorinated biphenyls, and petrochemicals) in health care or industrial settings may increase the risk for melanoma. However, the evidence for this increased risk is not very strong. Airline pilots have been found to have an increased risk for melanoma. It is uncertain, however, whether this higher risk is from excessive exposure to ionizing radiation at high altitudes, or because they have more opportunity to spend time in sunny regions.