1. Health

Melanoma

Description

An in-depth report on the causes, diagnosis, treatment, and prevention of melanoma.

Alternative Names

Skin Cancer

Risk Factors

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.

Tanning and Sunburn Risk

Skin Type

Tanning and Burning Risk

I

Always burns, never tans, sensitive to sun exposure.

II

Burns easily, tans minimally.

III

Burns moderately, tans gradually to light brown.

IV

Burns minimally, always tans well to moderately brown.

V

Rarely burns, tans profusely to dark.

VI

Never burns, deeply pigmented, least sensitive.

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).

Basal cell cancer
Basal cell cancer is a malignant skin tumor involving cancerous changes of basal skin cells. Basal cell skin cancers usually occur on areas of skin that are regularly exposed to sunlight or other ultraviolet radiation. Once a suspicious lesion is found, a biopsy is needed to prove the diagnosis of basal cell carcinoma. Treatment varies depending on the size, depth, and location of the cancer. Early treatment by a dermatologist may result in a cure rate of more than 95%, but regular examination by a health care provider is required to watch for new sites of basal cell cancer.
Click the icon to see an image of squamous cell cancer.

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:

  • Benign moles generally remain small with clearly defined, regular borders and uniform coloration. Some have a regular stippled 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.

Some specific moles or dark blemishes that either resemble melanomas, are risk factors for melanoma, or both include the following:

  • 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.
  • Liver Spots. Liver spots are usually evenly brown or tan sun-induced lesions that are universal signs of aging. Occurring most noticeably on the hands and face, these harmless blemishes tend to enlarge and darken over time.
  • 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) and often develop subsequent melanomas at additional locations. The risk for those with atypical moles and no family history of melanoma is less clear.
  • Blue Nevus. The blue nevus is 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.
  • 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 the cheeks. It is not harmful, but it may be difficult to differentiate from a melanoma, even for experts.
  • Congenital Nevi (Birthmarks). Whenever possible, very large birthmarks should be removed during infancy. Those known as giant congenital nevi are more than eight inches across and 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. Experts disagree, however, about whether small birthmarks need to be removed. Parents are advised to watch any birthmark for changes.

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

  • Non-Hodgkin's Lymphoma. Survivors of either non-Hodgkins lymphoma or melanoma face a higher risk for the other malignancy. These may have common causes, such as exposure to UV radiation or shared genetic factors.
  • Immunosuppressed Patients. Individuals whose immune systems are suppressed because of certain medications, organ transplantation, or specific medical conditions such as AIDS are also at risk. (Melanoma has also developed in patients who received heart transplants from donors who had the disease.)
  • Endometriosis. Endometriosis may put women with this condition at higher risk for melanoma, although more research is needed to confirm this.

Geographic Location

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.

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