Shedding light: The truth about the sun and skin cancer

From the July 8, 2008 edition of the Plain Dealer:

by Angela Townsend
Plain Dealer Reporter

For many of us, summer wouldn’t be summer without a beach vacation.

Or a tan.

Or both.

Most people are well aware of basic moves (avoid direct sunlight at peak hours, wear sunscreen and a hat) to keep from getting a sunburn and lessen the risk of skin cancer.

But there’s a lot more that you need to know. Here are some common myths.

Myth: Sun exposure is the only determinant of skin-cancer risk.

Truth: Genetic risk is an important factor, especially for melanoma, the deadliest form of skin cancer.

More than 62,000 cases of melanoma will be diagnosed in 2008, the Skin Cancer Foundation estimates. More than 8,400 people will die this year. Melanoma accounts for about 3 percent of skin-cancer cases but more than 75 percent of skin-cancer deaths. According to the American Cancer Society, melanoma most often starts on the torso of fair-skinned men and on the lower legs of fair-skinned women, but it can begin on other parts of the body as well.

Public-service messages focus so much on sun avoidance that family history often is overlooked, said Dr. Stephen Somach, president-elect of the Cleveland Dermatological Society.

"People with a family history of melanoma need to be checked carefully," he said. "With melanoma, they should be checked annually starting in the teenage years."

Most nonmelanoma skin cancers are associated with exposure to ultraviolet radiation from the sun. Other risk factors include a weakened immune system, chronic exposure to some chemicals and radiation for cancer treatment.

Myth: Tanning beds do not increase the risk of skin cancer.

Truth: Data suggest that tanning beds increase the risk of all skin-cancer types.

A 2002 study by Dartmouth Medical School found that people — especially young women — who used indoor tanning lamps increased their risk of developing skin cancer. Tanning lamps give off intense ultraviolet rays just like the sun does and can give people sunburns as if they were on the beach. The same risk exists for developing basal-cell, squamous-cell and melanoma skin cancer.

Each year, there are about 1 million cases of basal-cell carcinoma, the most common form of skin cancer. While rarely fatal, it can be highly disfiguring. Often misdiagnosed as a pimple, it’s most commonly found on the face and neck.

Squamous-cell carcinoma is often found on the lips, scalp and ears and is often misdiagnosed as a scab. About 250,000 people are diagnosed with this each year, with men diagnosed twice as often as women.

Myth: Faithfully using sunscreen will make skin cancer unlikely.

Truth: Sunscreen reduces the amount of penetrating ultraviolet radiation, and most sunscreens are formulated to protect you from burning. But sunscreen does not eliminate all UV radiation from damaging the skin, especially when there is excessive exposure to sun. Many people are unaware that sunscreen must be reapplied every two hours to remain effective.

"I think there’s a misconception that as long as one wears sunscreen, you can go out into the sun with impunity," Somach said. "People will spend more time in the sun because they feel protected."

But man, woman and child cannot live on sunscreen alone. It’s still crucial to cover the skin (the average cotton T-shirt has an sun protection factor of only 5 to 10) and to limit the time spent in direct sunlight during the peak hours of 10 a.m. to 4 p.m.

Myth: If you have dark skin, or it’s an overcast day or it’s sunny but cold outside, then you don’t need sunscreen.

Truth: Dr. Gisela Torres, a dermatologist at MetroHealth Medical Center, doesn’t mince words.

"You need sunscreen," she said.

"People of darker skin colors can and do still burn," Torres said. While black people, Latinos and other darker-hued folks are less likely to get severe or frequent sunburns, they shouldn’t go outdoors unprotected, she said.

"We may not need as high SPF as people with a fair skin type, but SPF protection is also important [in terms of] photo aging," she said. That’s a fancy way of saying wrinkles, dark spots and uneven skin tone that plague many people over 50. Sun damage is the main culprit.

Don’t let the absence of a typical summer-feeling day fool you.

Anyone who is outdoors for extended periods of time — golfers, gardeners, bikers, cyclists — needs SPF protection.

"The clouds are not a good cover or blocker for the sun," Torres said. Up to 80 percent of all UV radiation penetrates cloud cover, she said.

And in the winter? Skiers and other outdoor enthusiasts, take heed. Sun rays reflected by snow are intense enough to cause damage, she said.

Myth: As long as you don’t burn, your risk of skin cancer doesn’t increase.

Truth: A person’s skin-cancer risk is largely determined by cumulative UV light exposure, regardless of whether burning occurs, Somach said.

"If you’re disciplined and careful enough not to burn, that’s great — but your risk is dependent on total exposure," he said. So if you think you’re home free because you’ve never had a sunburn in your life, think again.

Between 40 percent and 50 percent of Americans who live to age 65 will be diagnosed with a type of skin cancer at least once.

The incidence of both melanoma and nonmelanoma skin cancer continues to increase. As a practicing dermatologist and dermatopathologist (one who is specially trained to interpret skin biopsies), Somach said it is not uncommon now to see skin cancer occurring in people in their 20s, 30s and, occasionally, in teenagers. That’s a big shift from years ago when skin cancer in people younger than 40 was rare.

Myth: Skin cancer occurs only in sun-exposed skin.

Truth: Skin cancer, especially melanoma, may occur anywhere on the body.

Somach tells the story about a man who developed melanoma in his armpit. "He had a family history of melanoma, but he thought it only occurred with sun exposure," he said. "The melanoma wasn’t diagnosed until it was too late." The man was in his early 30s when he died.

People may be fastidious about shielding their skin, but they often forget about their scalp and ears, Torres said.

Because baseball caps don’t cover the ears, that location is an especially high-risk area for skin cancer, she said. Like other squamous-cell carcinoma, it easily can spread to other parts of the body.

The ABCDE rule for early warning signs of melanoma:

A for ASYMMETRY

B for BORDER IRREGULARITY

C for uneven and multiple COLORS (tan, brown, black, red)

D for DIAMETER 6mm or greater

E for EVOLUTION, meaning significant changes in elevation, contour, or color

Look for moles that look or feel different from other surrounding moles. If you fell that something has changed, call a dermatologist.

 

What you should know about ultraviolet rays, sunscreen and sun protection factor, or SPF:

Sunscreen is chemically absorbed into the skin and works by reacting with skin cells. Sunblock contains zinc oxide to mechanically block the sun. Because it has fewer chemicals, dermatologists prefer sunblock for babies, young children and people with highly sensitive skin.

Either way, pick something that protects against both Ultraviolet A and Ultraviolet B rays. Apply sunscreen at least 15 minutes before sun exposure, then reapply every two hours. Dr. Gisela Torres, a dermatologist at MetroHealth Medical Center, recommends looking for products that have the following chemical agents she feels are most effective for blocking rays: avobenzone (or Parsol), Mexoryl, titanium dioxide or zinc oxide. The last two are physical barriers against the rays and are recommended for babies and people with sensitive skin.

Torres tells her patients to use an SPF of at least 30. For patients with a family history of skin cancer, she advises and SPF of 45 or higher with UVA protections.

Ultraviolet A, or UVA, rays: Longer and less intense waves than UVB but can penetrate glass and clouds. Penetrates more deeply into the skin, causing wrinklilng, leathering and sagging. Tanning beds use UVA, which is also a part of natural sunlight.

Replace sunscreen that is a year old or more because it becomes less effective with age.

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