It turned out to be not a mole, but melanoma, a potentially deadly form of skin cancer. It was localized and she didn't need chemotherapy or radiation treatment, but Donaldson endured a painful excision that removed a large chunk of skin from her stomach, as well as an infection.

The latest research shows that Donaldson is not unique among the young, who are experiencing a big increase in skin cancer. Even after research has tied tanning to skin cancers like melanoma and basal cell carcinoma, young people still see a tan as a fashion accessory and can be lax about protection.

In a recent American Academy of Dermatology poll, only half of those aged 18-24 said they are very or somewhat careful to guard against too much exposure.

RISING NUMBER OF CASES

An estimated 1.3 million cases of skin cancer will be diagnosed in the United States this year, according to the American Cancer Society. Melanoma will account for nearly 60,000 of them but cause four-fifths of skin cancer deaths.

In Canada, doctors will detect more than 80,000 skin cancer cases, and up to 5,000 of those will be melanoma, according to the National Cancer Institute of Canada.

More patients are women under 40. In fact, melanoma is now the most common cancer in women aged 25 to 29, according to the Skin Cancer Foundation.

A study published in the Journal of the American Medical Association last week showed the number of cases of non-melanoma skin cancer has tripled since the 1970s.

Researchers at Minnesota's Mayo Clinic said the rise in skin cancers in young people was disproportionate. They attributed the increase to the popularity of tanning, particularly among teenage girls.

Yet the dermatology academy's poll showed 61 percent of women 18 and older think they look better with a tan, and more than half think it makes them appear healthier.

TANS BECOME CHIC

It hasn't always been the case. Tanning was dismissed as gauche until the 1920s, when couture guru Coco Chanel returned from a vacation in the south of France with golden skin, instantly turning a tan into a fashion statement.

Fashion magazines and celebrities like Jessica Simpson and Lindsay Lohan help keep the trend alive. Tanning beds and tanning creams make it possible to get bronzed year-round.

Melanoma expert David Hogg said he is frustrated by the glamorous image. He compares tanning to smoking, saying with both people are willing to enjoy a quick benefit in the face of long-term risks.

"It's upsetting to those of us who have to deal with the consequences," said Hogg, a researcher and medical oncologist at Princess Margaret Hospital in Toronto.

Young people are particularly hard to reach, he said. "The younger you are, the shorter your horizon of harm is."

Donaldson now makes frequent trips to doctors to make sure the cancer has not returned in a different place, and her risk of developing another melanoma is now higher.

As a child, she wore sunscreen because her mother slathered it on, but in her teens and 20s she often tanned on the beach with friends in southern California.

"It looked healthier, we thought, than being white," she said.

Tanning and sunburns aren't the only causes of the cell changes that lead to skin cancer. Daily sun exposure adds up over time and is even more damaging when the UV index is high, as it has been across North America this summer.

FOCUSING ON EDUCATION

Before her diagnosis, Donaldson believed if she developed cancer, doctors would just scrape it off. When it happened, friends also showed ignorance about the seriousness.

"'You had all that for melanoma? Isn't that just skin cancer?' That was something I heard all the time," she said. "It was like a slap in the face."