To bask or not to bask

Sun exposure causes skin cancer. But we need it to make vitamin D. So just how much is too much?

May 05, 2006|By JONATHAN BOR | JONATHAN BOR,SUN REPORTER

Two years ago, a Johns Hopkins Hospital dermatologist lost three women in their 30s to melanoma, an insidious skin cancer that is widely and erroneously considered a disease of older people.

What shocked Dr. Rhoda M. Alani was not only the patients' age, but also that they died from tumors less than a millimeter deep that rapidly spread to other parts of the body. Within months of their diagnosis, the women were gone.

"I went to one of the women's funerals and it was almost too much to bear," said Alani, noting that the patient left children ages 1 and 3.

The experience changed the focus of Alani's research to discovering the genetic factors that enable some tumors to spread at such alarming rates. The answer remains a mystery, but she and other doctors agree that Americans' quest for the perfect tan is at least partly to blame for increasing rates of skin cancer -- including melanoma, the deadliest kind.

"We don't know specifically how the sun causes melanoma, and we don't know the specific genes that are affected by the ultraviolet light," she said. "But the bottom line is that sun exposure causes cancer."

The problem is that sunshine -- in small quantities at least -- can also be beneficial because it prompts the body to make vitamin D. The vitamin helps build strong bones by promoting the body's absorption of calcium. Without enough, bones can become thin, brittle and misshapen, according to the National Institutes of Health.

Recently, experts at Harvard and Boston universities have challenged the accepted wisdom, arguing that Americans risk depriving themselves of sunlight's health benefits -- particularly vitamin D production -- if they go overboard in shielding themselves.

That leaves millions wondering where to draw the line.

Scientists estimate that excessive sun exposure is responsible for about 60 percent of the 60,000 cases of melanoma diagnosed last year in the United States. More than 90 percent of basal and squamous cell carcinomas -- the less-serious forms of skin cancer -- are linked to the sun.

According to the National Cancer Institute, melanoma rates rose an average of 3 percent a year between 1978 and 2002, though early detection and improved surgical techniques kept deaths stable at about 8,000 annually.

The trend has spurred a flurry of melanoma awareness campaigns, with doctors and health organizations such as the American Academy of Dermatology urging people to slather on sunscreen whenever they venture outside and to check their bodies regularly for suspicious moles.

Brittany Lietz, a 21-year-old student at the University of Maryland School of Nursing, needs no convincing. Last year, she consulted a dermatologist about a nickel-sized mole on her back that had irregular edges, brown and red coloration, and a tendency to bleed when scratched.

What she didn't know at the time was that these were classic signs of melanoma, a cancer that causes the skin's pigmented cells to multiply uncontrollably. Two biopsies confirmed that she had the disease, and now she bears a 14-inch scar across her back where surgeons at Hopkins carved out the mole.

"I am the picture of someone who is at very, very high risk for skin cancer," Lietz said, noting her blond hair, blue eyes and fair skin. But there was something else. Although she said her mother was careful to protect her from the sun, Lietz developed an "addiction" to tanning beds during her senior year of high school.

A few months away from her senior prom, Lietz decided that a modest tan would be a nice complement to the white dress she planned to wear.

"I told myself that I was going to stop after the prom, but it becomes an addictive process," said Lietz, who holds the pageant title of Miss Tidewater. "You're used to having that color all the time and you keep on going. So I continued for a year and a half, going at least four times a week."

Since her surgery, she regularly sees a dermatologist, who has removed 20 suspicious and possibly precancerous moles, leaving pin-prick scars all over her body.

Her experience is far from unique. Dr. Jennifer Cooper, a dermatologist at the University of Maryland Medical Center, said she's seen three young women in the past six months who developed melanoma after using tanning beds.

Doctors caught the disease early in each case, and the patients have lived without recurrences since their surgery. One of them, however, developed another primary tumor -- one that arises independently rather than from the spread of earlier cancers.

"The problem with melanoma is that we don't have great treatments once the melanoma has progressed," said Cooper. Surgery can save patients whose tumors are caught early, but scientists have yet to find chemotherapy or radiation treatments that improve survival rates in advanced cases.

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