One in five Americans and one in three Caucasians will develop skin cancer in the course of a lifetime.

R.J. Ignelzi, Contributor

In a world of sound bites and Internet rumours, it's not always easy to distinguish fact from fiction. But when it comes to skin cancer, being able to exclude the myths and embrace the truth may save your life. Skin cancer is the most common form of cancer in the United States.

More than one million cases are diagnosed annually, according to the National Cancer Institute. One in five Americans and one in three Caucasians will develop skin cancer in the course of a lifetime. Melanoma, the deadliest form of skin cancer, is now the second most common cancer in women between the ages of 20 and 29, the American Cancer Society says. It claims an estimated 8,000 lives annually in the United States and will strike 62,000 Americans this year.

Meanwhile, the rates of basal-cell carcinoma and squamous-cell carcinoma - the two less-lethal forms of the disease - have more than doubled in the past generation among 20- and 30-somethings, says a 2005 report from the Mayo Clinic. But not all the statistics are so dismal. More than 90 per cent of all skin cancers are preventable, and with early detection, the survival rate for people with skin cancer is about 99 per cent. The key to preventing and surviving skin cancer is knowing the facts about the disease and sun damage.

MYTH VS REALITY

Dermatologists clear up some common misinformation and misconceptions about skin cancer and sun protection:

MYTH: You can prevent skin cancer by putting on one application of sunscreen at the start of beach day.

Using sunscreen daily is a good habit to get into. But smearing it on only after your morning shower can give a false sense of security."One application of sunscreen is not good for the day. We sweat it off and it rubs off and we need to reapply it every two to three hours," says Dr. Susan Stuart, a dermatologist at Scripps Memorial Hospital in San Diego, noting that most people need enough sunscreen to fill a four-ounce glass to cover their body's surface.

But, no matter how much or how well you apply sunscreen, it still only givesa certain amount of protection. "Even with a high-SPF sunscreen, you still get some sun," says Dr. Curt Littler, a dermatologist with Sharp Rees-Stealy Medical Center in San Diego. "In addition to wearing sunscreen, you also need to avoid the sun as much as possible during midday and wear protective clothing."

MYTH: Visible symptoms of skin cancer will show up within a year or two of bad sunburns.

The risk of skin cancer is based on accumulative sun damage. "It's not an overnight phenomenon. You can develop skin cancer 10, 20 or 30 years down the pike," says Stuart, who adds that skin damage such as wrinkling, blotchiness and a leathery appearance can show up weeks or months after the sun exposure."More than one bad sunburn in childhood puts you at risk for skin cancer for the rest of your life," says Dr. Richard Gallo, chief of the division of dermatology at University of California San Diego Medical Center.

MYTH: Getting a base suntan protects you from skin cancer.

The term 'healthy tan' is a contradiction in terms. A tan is really a sign of injury to the skin. In an effort to protect itself from further damage, the skin cells produce a pigment called melanin, which darkens the skin. By the time the tan develops, permanent damage has been done and will someday show up in the form of wrinkles, blotches, sagging tissue and even skin cancer."There is no such thing as a safe tan. No matter if you're tanning your skin or burning your skin, it's all sun damage," Stuart says.

MYTH: Tanning salons will not give you skin cancer.

"A tan from a suntanning parlour is the worst kind of tan," says Dr. Mitchel Goldman, dermatologist and assistant professor of dermatology at University of California San Diego. "There have been a number of studies showing that (people who regularly use tanning salons) have a higher rate of malignant melanoma, because the ultraviolet A rays used by tanning salons penetrate deeper into the body."

The San Diego Union-Tribune librarian Beth Wood contributed tothis report. Visit Copley News Service at www.copleynews.com.