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New Risk Factors for Melanoma

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99% Curable When Caught Early… Deadly, When Not

Melanoma — it’s scary but solvable, if caught before it spreads. The deadliest form of skin cancer, melanoma is responsible for 75% of all skin cancer deaths but is 99% curable in the early stages. As yet no particular melanoma gene has been identified, which makes it even more critical to understand the factors associated with the disease to encourage early detection and sun-smart behavior. A number of recent studies shed new light on who should worry — with a far longer list of associated traits than the blue eyes, freckles and history of sun exposure we’ve been hearing about for years and years.

Darrell S. Rigel, MD, clinical professor of dermatology at New York University Medical Center, and a colleague examined factors common among 600 people (300 melanoma patients and 300 who did not have the disease), age and gender matched from age 21 to 80, to identify which were most often associated with melanoma. They came up with a list of 43 different factors, then conducted a multivariate analysis that ferreted out six characteristics that each independently predicted melanoma. These are (in no particular order):

1. A history of blistering sunburns as a teenager.

2. Red or blonde hair.

3. Marked (meaning the number totaled more than 100) freckling of the upper back, which indicates excessive sun exposure along with a person’s susceptibility to the sun, due to the fact that they are less likely to form a protective tan.

4. A family history of melanoma.

5. A history of Actinic Keratoses (AKs), which are lesions on the skin considered to be precursors to skin cancer.

6. Outdoor summer jobs for three or more years as a teenager (where he/she was likely to have had excessive sun exposure).

DO THE MATH: ARE YOU AT RISK?

Each of these factors separately predicts an increased lifetime risk of melanoma, regardless of the others, Dr. Rigel said. While the average American has a 1.5% lifetime risk of developing melanoma, having just one of these six factors increased lifetime risk to 3% to 5%… two or more boosted risk five to tenfold… and a person with three or more factors has a 10 to 20 times increased lifetime risk of developing melanoma. Dr. Rigel presented the findings at the 67th Annual Meeting of the American Academy of Dermatology.

The goal of the study was to “simplify the modeling” of melanoma so “you don’t need to be a doctor to be able to identify yourself as being at high risk,” Dr. Rigel explained. The reasoning: Realizing they are in greater danger, people can modify their behavior to reduce their risk, using sunscreen more aggressively, wearing a hat, sunglasses and protective clothing when in the sun, and being very vigilant about seeing the dermatologist for annual skin cancer screening. Dr. Rigel urges even more caution and screenings if you “have three to four of these factors, and especially if something looks suspicious on your skin.”

Along with this study comes a plethora of research from other sources identifying other risk factors, behaviors and traits that are associated with melanoma. For instance:

  • For people with a prior history of breast cancer, melanoma risk is two to three times higher.
  • Women with a prior history of thyroid cancer are at double the risk of developing melanoma.
  • A higher incidence of melanoma is linked to higher socioeconomic class.
  • Airline flight personnel have a higher rate of melanoma, due to cosmic radiation and solar flares.
  • Male drivers have a higher incidence of skin cancers on the left side of the body compared with the 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 quartile of height.
  • Use of tanning beds is a major risk factor for melanoma.
  • People with a prior history of dysplastic nevi (non-cancerous moles) and a family history of melanoma have a 50% greater risk of developing melanoma.

Finally, scientists may have identified a gene that is likely to contribute to melanoma in women under 50 years of age. At NYU School of Medicine, David Polsky, MD, PhD, and colleagues identified a genetic variation that leads to a four-times greater risk of melanoma in women under 50 compared with those over 50. The gene, called MDM2, appears to be activated by estrogen, a hormone that is produced in abundance by pre-menopausal women. These findings may lead to the development of a genetic test that can identify young women at higher risk for melanoma. The study appeared in the April issue of the journal Clinical Cancer Research.

“Melanoma is a clear-cut case in which early detection is key… if you catch it early, you can cure it,” said Dr. Rigel. “Once it’s advanced, nothing works.”

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Source: Darrell S. Rigel, MD, is clinical professor of dermatology at New York University Medical Center. Date: July 7, 2009 Publication: Bottom Line Health
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