DescriptionAn in-depth report on the causes, diagnosis, treatment, and prevention of melanoma.
Alternative NamesSkin Cancer
In the US, the incidence of melanoma is rising more rapidly than any other cancer. During the 1970s, the incidence of melanoma rose by about 6% a year. On a positive note, since the early 1980's this has slowed to an increase of 3% a year. At this time, men have a lifetime risk for melanoma of 1.75% and women of 1.23%. In 2003, some 54,200 Americans will develop melanoma--about 29,900 men and 24,300 women.
An estimated 7,600 Americans are expected to die from it this year, 4,700 men and 2,900 women. Survival rates have been improving, however, and the increase in melanomas has occurred principally with thin, less aggressive forms of the disease. Some experts believe this is due to the increased awareness from effective public programs and earlier diagnosis.
Age and Gender
Melanoma in Adults. Melanoma is most common in people over 40 and the incidence increases significantly as people get older. Before age 40, melanomas are slightly more common in women than men, but after age 40 men are more often affected. Men are also more likely to have invasive and fatal melanoma than are women, although some research suggests that the higher rates are only because men fail to seek a diagnosis of suspicious skin changes before they become dangerous. The rate in women levels off somewhat between age 45 and 60; researchers speculate that menopause could have some sort of protective effect during those years.
Melanoma in Children. Melanoma is rare in children under age 10. Among children ages 10 to 14 the incidence is only 0.3 per 100,000 and between ages 14 and 19, it is still very rare, 1.3 per 100,000. Parents, then, should not be unduly alarmed by every minor skin imperfection in their children. Nevertheless, melanoma is as serious in children as in adults and early detection is still critical.
People at Higher Risk for Melanoma from Intense Exposure to Sunlight and Ultraviolet Radiation
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 than people with other skin types for developing melanoma. The risk increases for those who are easily sunburned and rarely tan, particularly if they live close to the equator where sunlight is most intense. Darker ethnic groups or those with swarthy complexions are not immune, however.
Experts have devised a classification system for skin phototypes (SPTs) based on the sensitivity to sunlight. It ranges from SPT I (lightest skin plus other factors) to IV (darkest skin). Tanning and Sunburn Risk 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.
People Exposed to Intermittent Intense Sunburns. Whereas some skin cancers, such as squamous cell and basal cell carcinomas, are associated with cumulative lifetime exposure to the sun, melanoma is more often linked to intermittent intense exposure to sunlight, particularly during childhood and adolescence. Cancer typically arises many years later.
Fortunately, many parents are now taking effective steps to protect their children, although experts worry that they are relying too much sunscreen and less on other protective measures. Adolescents, however, are at special risk for sun-related cancers because, according to a 2002 study, the majority fails to take protective measures when out in the sun. According to the study, boys are less likely to use sunscreen than girls, but girls have more sunburns and use tanning salons more often. Adults who work indoors and experience the occasional weekend sunburn may also be at increased danger.
Interestingly, a number of studies report that continuous exposure to sunlight during adolescence or adulthood may be protective.
Exposure to Tanning Parlors. Tanning beds and parlors have been possibly linked to a higher incidence of nonmelanoma skin cancers, though the link to melanoma remains unknown.
Personal or Family History of Melanoma
Individuals who have been diagnosed with melanoma are at increased risk for a second primary melanoma. According to one 2003 study, the risk over time for developing a second melanoma is 1% in the first year after diagnosis, 2.1% at five years, 3.2% at 10 years, and 5.3% at 20 years. The risk is especially higher in older men and in those with first melanomas on the upper body and face.
People with family members who have or had melanoma should also be considered at high risk and examined on a regular basis.
Other Skin Conditions That Increase the Risk for Melanoma
Nonmelanoma Skin Cancers. Nonmelanoma skin cancers, including basal and squamous cell carcinomas, increase the risk of dying from other cancers, including melanoma itself, lung cancer, non-Hodgkins lymphoma, bladder cancer, and leukemia as well as testicular and prostate cancers (in men) and breast cancer (in women).
Moles (Nevi) and Other Dark Blemishes. Any mole (called a nevus) or other blemish that seems new, changing, or unusual in any way should raise suspicion, but one should not be alarmed by every rash or bump. Benign (noncancerous) moles (nevi) typically have the following characteristics:
Some specific moles or dark blemishes that either resemble melanomas, are risk factors for melanoma, or both include the following:
The more moles one has the higher the risk that one of them will become cancerous, although the danger is still very small. A 2003 study estimated that the risk for a single mole to develop into melanoma by age 80 is 1 in 3164 in men and 1 in 10,800 for women. (The risk is higher, however, with atypical moles. One study of people with melanoma indicated that the presence of even one atypical mole doubled the normal risk and having 10 or more increased the chance 12-fold.) Any moles should be watched for changes, particularly in people with fair skin and other risk factors. However, simply having them should not cause alarm.
Psoriasis and Its Treatments. Psoriasis increases the risk for squamous cell carcinoma, but studies conflict on whether it has any effect on melanoma. One study, in fact, reported a lower risk. Nevertheless, there is some evidence that long-term treatment for psoriasis using UVA radiation (PUVA) may increase the risk for melanoma. In one study, there was a significantly higher risk even with relatively few treatments. In one study, invasive melanoma had occurred in 2.8% of patients 15 or more years after the initial treatment.
Non-Skin Medical Conditions
Australia has the highest melanoma rate in the world. In the US the incidence is highest in California, Florida, and Texas. The disease is by no means limited to such sunny states and countries, however. In general, the risks are highest in regions where the population tends to be blonde and fair-skinned. Norway, for example, has had the highest rate of melanoma in Europe, and rates are soaring in the UK, particularly among men, perhaps because Britons are increasingly vacationing in sunny climates.
Other Forms of Radiation Exposure
Occupational exposure to radiation, such as in health-care or industrial settings, may increase the risk for melanoma. Airline pilots, too, are at 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. Experts disagree over whether frequent flyers are also at increased jeopardy.