Six factors independently predicted melanoma risk

Mar 5 2009

Melanoma, the most serious form of skin cancer, is a health risk that accounts for more than 75 percent of all skin cancer deaths, according to the American Cancer Society (ACS).

Looking at this sobering statistic another way, it is estimated that one American dies from melanoma almost every hour (every 62 minutes). While those at higher risk of developing melanoma typically have included fair-skinned individuals who sunburn but don't tan easily and have a history of sunburns, new research has identified other factors that could increase a person's risk of melanoma.

Speaking today at the 67th Annual Meeting of the American Academy of Dermatology (Academy), dermatologist Darrell S. Rigel, MD, FAAD, clinical professor of dermatology at New York University Medical Center (NYU) in New York, presented new research which identifies six factors that independently predicted melanoma risk in 600 people.

"Since we haven't identified the gene responsible for melanoma yet, we can't screen people with this gene who we know would be at risk for melanoma," said Dr. Rigel. "Similar to how those with the known BRCA2 gene are carefully screened for breast cancer, we hope to one day be able to screen people that carry the melanoma gene. Until then, we have to rely on indirect measures or risk factors that we know are common to people who develop melanoma to try to educate those individuals to get regular skin exams by their dermatologist."

In a pre-published study conducted by Dr. Rigel and a colleague at NYU Medical Center, data from characteristics of 600 people - including 300 melanoma patients and 300 control patients (those who had not had melanoma) - were examined to try to determine what factors varied between the two groups and were most often linked to melanoma. From this research, Dr. Rigel created a new model of six factors that independently predicted melanoma risk which could be used as a quick screening method for people to assess their own risk.

The six factors Dr. Rigel identified, which include some melanoma risk factors that have been previously identified, are as follows:

1. History of blistering sunburns as a teenager
2. Red or blonde hair
3. Marked freckling of the upper back - a sign of excessive sun exposure and that a person is susceptible to it
4. Family history of melanoma
5. History of Actinic Keratoses (AKs) - considered the earliest stage in the development of skin cancer
6. Outdoor summer jobs for three or more years as a teenager

"When conducting this study, we looked at 43 different factors and these six factors independently predicted melanoma risk," said Dr. Rigel. "In the average U.S. population, the lifetime melanoma risk is about 1.5 percent for an invasive melanoma and about 3 percent for all types when you include in situ melanomas. So if you have any one of these six factors, your melanoma risk goes up to about a twofold to threefold increase over the general population - or roughly a 3 percent to 5 percent lifetime risk of developing melanoma with any one of those factors."

Dr. Rigel added that for individuals with two or more of these factors, the risk goes up to a five to 10 times increased lifetime risk of melanoma over the general population. In addition, those with any three or more of these six factors have up to a 10 to 20 times increased risk of developing melanoma.

Other previous studies examining risk factors for melanoma have shown correlations between melanoma and a range of associations - from certain types of cancers to socioeconomic class. Examples of these previous studies include:

• Women and men with a prior history of breast cancer have a twofold to threefold risk of developing melanoma.
• Women with a prior history of thyroid cancer have a twofold risk of developing melanoma.
• A higher socioeconomic class has been linked to a higher incidence of melanoma, which Dr. Rigel attributes to this group being able to afford more vacations and leisure time that could result in more sun exposure.
• Airline flight personnel had a higher rate of melanoma when the incidence of melanoma was examined by occupation.
• Male drivers have been found to have a higher incidence of skin cancers on the left side of the body compared to right side of the body.
• Taller men were found to have a higher incidence of melanoma than shorter men, with men in the top quartile of height twice as likely to develop melanoma as men in the bottom quartiles of height.
• Use of tanning beds is a major risk factor for melanoma, with studies showing people who use tanning beds have a higher melanoma risk, a higher incidence of getting a second melanoma, and are younger when they develop melanoma.
• Patients with a history of dysplastic nevi, or non-cancerous moles that share some of the features of melanoma, and a family history of melanoma have a 50 percent greater risk of developing melanoma.

"Dermatologists continually look for clues as to who is most likely to develop melanoma, and this ongoing research will likely help more people understand their own risk factors and may convince them to get regular skin cancer screenings," said Dr. Rigel. "Unfortunately, we expect skin cancer rates to continue to climb. But, identifying additional risk factors for melanoma could lead to the early detection and successful treatment of this potential killer."

People who are known to have any of the risk factors for melanoma should regularly conduct skin self-examinations and see a dermatologist.

For more information on melanoma, go to the "SkinCancerNet" section of www.skincarephysicians.com, a Web site developed by dermatologists that provides patients with up-to-date information on the treatment and management of disorders of the skin, hair and nails.

Headquartered in Schaumburg, Ill., the American Academy of Dermatology (Academy), founded in 1938, is the largest, most influential, and most representative of all dermatologic associations. With a membership of more than 15,000 physicians worldwide, the Academy is committed to: advancing the diagnosis and medical, surgical and cosmetic treatment of the skin, hair and nails; advocating high standards in clinical practice, education, and research in dermatology; and supporting and enhancing patient care for a lifetime of healthier skin, hair and nails. For more information, contact the Academy at 1-888-462-DERM (3376) or www.aad.org.