Back in her younger years, Patty Stevens was the ultimate sun worshiper. Always seeking "that healthy glow," as she called it, she worked on her tan with a passion.

She tanned at the pool, in her back yard, on campus, anywhere the rays were abundant. In the spring, she got a running start with a burn — tiny blisters, slight peeling and more sun on top of that.

"I was in the sun every time it came out. I just loved it," said Stevens, 46. "That's what kids did ... I just never thought about the possibility of damage down the road."

But Stevens has had more than her share of sun damage. In the past five years, she has had more than 100 skin cancers — including one that seriously threatened her life and left her hobbling from cancer surgery in her right leg.

Now as the Northwest heralds summer and the "tanning season," thousands of people statewide could be setting themselves up for a fate similar to that of Stevens. Cellular damage wreaked by the sun's ultraviolet radiation can show up as cancer years later.

More than 1 million new cases of skin cancer will be diagnosed in the United States and 10,600 people will die this year, according to the American Cancer Society. That's more than half of all the new cancers predicted this year in the United States.

Melanoma, the best known, deadly skin cancer, will be found in nearly 106,000 people this year, including about 1,380 in Washington state. Statewide, the incidence rate is increasing nearly 6 percent a year, now amounting to about 38 per 100,000 population, compared with about 29 per 100,000 nationwide. State and national statistics are not kept on the less dangerous, but common cancers: basal cell carcinoma and squamous cell carcinoma.

"Skin never forgets"

No one knows why Washington residents have a higher risk for melanoma than others. But experts have some theories about this state and why the incidence has tripled nationwide since 1980.

Despite warnings about the sun's dangers, tans seem to be more popular than ever. The ozone layer is getting thinner, allowing more harmful ultraviolet rays through. And the indoor-tanning industry has boomed in the past 25 years.

"Tans are sexy. Or at least people think they are," says Dr. Dan Berg, director of dermatologic surgery at the University of Washington. "But now I look at a tan ... and it looks like cooked skin. That's what it is."

Washington residents' higher incidence for melanoma is mainly in urban areas. Experts speculate that contributing factors could be the abundance of fair-skinned residents of Scandinavian heritage; the migration of Californians, who generally have had more sun exposure; and a propensity to overreact to the return of the sun each summer.

In cities, "people spend a lot of time indoors. Then our two sunny months arrive and they go outside and fry themselves," says Dr. Juliet Van Eenwyck, state epidemiologist for non-infectious conditions.

Damage to skin cells comes from the sun's ultraviolet rays. Too much ultraviolet radiation damages DNA, changing its structure slightly. Most cells naturally repair themselves, but some are injured and go through life more vulnerable to additional sun damage. In time, they might become cancerous.

"It's like a deer traveling in the desert with an injury to its leg," says Berg. "It's alive, but weak; it's a sitting duck for more damage, including being eaten by a lion.

"The damage to cells is cumulative. Skin never forgets."

Children who have had one or more bad sunburns have an increased risk of cancer as an adult. Burns as an adult also increases the risk. About 1 in 5 Americans is now expected to develop a skin cancer in his lifetime, says the American Academy of Dermatology.

Patty Stevens' skin certainly remembers her sun-baked days of youth. Dozens of white spots mark the fair skin of her arms and legs, which, unlike her face, went without tanning lotion during her tanning sessions.

The spots are scars from the removal of squamous cell carcinomas, one the most prevalent skin cancers. The cancers began appearing when she was 32 and have accelerated so much in the past five years that she now gets checked by Berg every four weeks. Treated early, squamous cell carcinoma — like all skin cancers — usually can be cured. Left alone, it can grow and occasionally spread, causing disfigurement and, sometimes, death.

Stevens faced another, more frightening threat last July. A small, shiny, red bump on her knee turned out to be Merkel cell carcinoma, a rare, fast-moving and potentially deadly cancer. Within a week of the discovery, it already had spread, and 22 lymph nodes in her right groin had to be surgically removed. Six weeks of radiation followed, then regular physical therapy and acupuncture to help her walk better.

Today, Stevens is happy that MRI tests show she is free of the cancer. But she walks painfully on her tiptoes and hopes therapy will bring her back to normal. She also does not relish her regular trips to the clinic, where Berg continues to find squamous cell cancers ranging from the size of a nickel to a 50-cent piece. They must be scraped off, and the wounds carefully tended for weeks.

"It's a drag," says Stevens, who has had to stop her work in construction management. "It's almost become a way of life, which is sad."

Besides increasing the risk of skin cancer, longtime heavy sun exposure can cause premature aging of the skin. Ultraviolet rays break down elastin, a fibrous protein that maintains skin tone, and cause wrinkles and skin sagging.

The sun's UV rays also can cause cataracts, a clouding of the lens in the eye; damage to the immune system; and scaly growths called actinic keratoses that can develop into skin cancer.

Darker-skinned people have a lower incidence of skin cancer because they have more melanin, or skin pigment, which is protective. But they still can develop the cancers, especially acral lentiginous melanoma, a less common form of melanoma not caused by sun exposure. It is most often found in areas not exposed to the sun — on the palms, soles of the feet, under nails or in the mouth.

Tanning bed worries

Despite the evidence that too much sun is harmful, tans remain ever popular, according to a national survey this year sponsored by the American Academy of Dermatology.

Two-thirds of respondents said people look better with a tan, and about one-third of men and one-fourth of women said they weren't careful about sun protection. Residents of Western states are most likely to get sunburned, with about one-third saying they had been recently burned.

Teenagers didn't worry much about the sun. More than 80 percent knew sunburns increased their risk of skin cancer, but 60 percent got sunburned last summer. More than two-thirds said they know unexposed skin areas can develop cancers, but about one-third of girls ages 15 to 17 said they used a tanning bed last year.

Health authorities aren't big on indoor tanning.

The World Health Organization recently recommended that no one younger than 18 use a tanning bed. Both the Food and Drug Administration and Centers for Disease Control and Prevention discourage the use of tanning beds and sun lamps. And the American Medical Association and American Academy of Dermatology have urged a ban on the sale or use of tanning equipment for non-medical purposes.

Many tanning parlors say their beds mainly emit "safe" UVA rays rather than UVB rays, which are more likely to burn. But UVA penetrates deeply into the skin, and several studies have linked the rays to melanoma. A recent Dartmouth Medical School study of nearly 900 skin-cancer patients found that the use of any tanning device increased the risk of squamous cell carcinoma by 150 percent and the risk of basal cell carcinoma by 50 percent.

Dr. Robin Hornung, chief of dermatology at Children's Hospital & Regional Medical Center, is an expert on tanning devices and people's use of them. She found in a recent North Carolina study that 95 percent of tanning-parlor patrons exceeded FDA-recommended exposure limits and about one-third began tanning at the maximum recommended doses. Yet many states, including Washington, have no regulations regarding the parlors.

"There are so many cases of burns; people are getting injured," said Hornung, who supports regulations. "Many don't believe (indoor tanning) can cause cancer, too."

Cancer specialists such as Berg say people obviously don't need to avoid all sun exposure. You have to live your life, they say.

But avoiding the midday sun and protection with sunscreen with at least an SPF 15 rating are important measures, experts say. And sunscreen does allow enough UV radiation for the body to create vitamin D, Berg says. The vitamin is needed for absorption of calcium and phosphorous from the intestines, building strong bones and, some scientists believe, fighting cancer.

Any burn is unhealthy, says Berg. And don't think sun damage can't happen to you, says Stevens.

"I'm living proof of that," she says. "It's so insidious, you don't know it's happening ... when you have your beautiful tan."

Warren King: 206-464-2247 or wking@seattletimes.com