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June 09, 2004

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Palo Alto Online

Publication Date: Wednesday, June 09, 2004

Rays of skin cancer Rays of skin cancer (June 09, 2004)

Dermatologists caution sun-worshippers to apply sunscreen and wear protective clothing as statistics show melanoma increasing

by Terry Tang

Along with sand and surf, the lazy, hazy days of summer bring renewed alerts about early detection and prevention of skin cancers like melanoma.

Yet, as beach bums focus on tanning their bodies to highlight flesh-baring fashions, the importance of sunscreen and sun-sense tends to be an afterthought, despite the fact that melanoma is becoming more prevalent in young adults.

"I've seen people who are about to start college and I tell them 'you have melanoma,'" said Dr. Renata Mullen, a dermatologist with the Palo Alto Medical Foundation. "And it puts a cloud on everything."

The American Cancer Society estimates this year the state will have 5,020 new cases of melanoma -- which is triggered by sun exposure -- surpassing projections in the rest of the U.S. On average, Mullen's office sees a couple of new melanoma cases each month involving 18 and 19-year-olds. Luckily, all the diagnoses have come early.

It's statistics like these that have Stanford and the Palo Alto Medical Foundation hoping to better educate the public on the importance of sun safety. In May, the Stanford University Medical Center held its annual skin cancer detection event at the Stanford Shopping Center.

Education is most important during childhood since, "by age 20, you will have had 75 to 80 percent of your total lifetime of sun exposure," said Dr. Susan Swetter, associate professor of Dermatology at Stanford. In addition, young adults, typically females, use tanning salons, which are equally hazardous.

Mullen believes the public is generally complacent about covering up and slapping on sunscreen. If parents stressed the matter more, kids would follow.

With global warming and a diminished ozone layer, more of the sun's damaging ultraviolet rays -- classified as UVA and UVB -- invade the atmosphere. Scientists believe that UVB is clinically more carcinogenic, according to Swetter. UVA, which makes up the majority of the rays that touch the skin, can penetrate deeper and even through glass. Furthermore, it can leave more "photo damage" such as wrinkles, fine lines and possibly cataracts.

Skin color and genetics also play roles in sun-proofing. Melanocytes, pigment-producing cells in the skin, create melanin, a dark brown or black pigment. Generally, fair-skinned people have less pigment production and are more prone to getting melanoma.

People with darker-skin, however, shouldn't shrug off skin cancer warnings. Those who tan easily are not invincible against skin cancer either. Melanoma sometimes develops in less pigmented areas in the form of a typical mole. Other times, a person may not show symptoms immediately.

"The other (myth) is that you can only get it in sun-exposed areas," said Dr. Renata Mullen, a dermatologist with the Palo Alto Medical Foundation. "You can get it in the genital area, in the scalp, between the toes. It's less common but, when you check your skin, you should check there. "

The best way to shield against the harmful rays is to wear sunscreen.

"People who are living in California, I'd say, should wear it every day unless it's raining," Swetter said. Areas that warrant coverage include "on the face, tops of your hands. If you do that, you can prevent an excessive amount of sun exposure."

An ideal sunscreen combines chemical and physical agents to shield UVA and UVB rays. Avobenzone, a primary chemical in sunscreens, reacts in the skin by converting itself into a UVA-combative ingredient. Physical sun-blockers, consisting of titanium dioxide or zinc oxide, work by reflecting and scattering most UVA and UVB rays. Both are manufactured in a "microfine" form and penetrate the skin easily. These changes in sunscreen have occurred only within the past few years.

In terms of application, people should be dabbing on the equivalent of two ketchup packets every two hours. Even if the product promises to be water-resistant, individuals should still re-apply lotion. More importantly, nobody should exceed the time allotted by their sun protection factor. And slathering a higher SPF later won't buy more hours against your rate of sun-burn.

"The issue that the FDA had in 1999 is that with the difference in sun protection between SPF 30 and SPF 45, you're not getting that much more," Swetter said. "It's very miniscule."

Nowadays, there are more companies specializing in sun-protective clothing for young and old. Consumers can purchase shirts, pants and hats that provide SPF protection. Typically, the clothes are made from tightly woven material and labeled with an SPF number. But, youngsters tend to put brand-name and style above saving their own skin.

"When you look at the in-between group, like teenagers and young adults who want to look stylish, there's not a whole lot," Mullen said. "That's something they need to work on. Someone like Calvin Klein needs to pick this up"

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