Do Sunscreens Save Your Skin?

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Cedric and Frank Garland sure know how to put a cloud over a sunny day. Since 1990 the two brothers and their research associate Edward Gorham, all San Diego-based epidemiologists, have spread a highly unsettling message: liberal use of sunscreens may actually promote a deadly form of skin cancer called melanoma rather than protect people from it.

The Garlands admit that sun blocks filter out the most damaging solar rays and prevent sunburn. But that allows fair-skinned people to stay on the beach or golf course longer than would otherwise be tolerable. Lulled into a false sense of security, these sun worshippers suffer the cumulative effect of overexposure to the type of radiation that penetrates their sunscreen and, the Garlands say, can lead to malignancy. "It's time to step back and to consider whether what we have been doing, specifically the strong use of sunscreens, is working," says Cedric, a professor at the University of California at San Diego.

Mother Jones magazine featured the Garlands' hypothesis on the cover of its current issue. The American Academy of Dermatology, which has denounced the San Diego team's work in the past, again blasted their conclusions as unfounded, saying that they could undermine efforts to educate the sunbathing public about skin cancer. The Food and Drug Administration has not yet weighed in on the controversy. Last week, however, the agency asked sunscreen manufacturers to put warnings on their lotions about the harmful effects of overexposure to the sun. And so, as the countdown proceeds to the annual Memorial Day migration out of doors, the untanned masses must rely, once again, on their own best judgment. A close look at the evidence suggests that sunscreens are neither the absolute villain the Garlands make them out to be nor the perfect safeguard that beachgoers want.

No one doubts that the sun's toll is rising. One in 6 Americans will suffer from skin cancer, and the incidence is increasing nearly 4% annually. Of the 700,000 new cases that will be diagnosed in the U.S. this year, 80% will involve cells found in the lower layers of the epidermis. These so-called basal-cell cancers develop slowly, spread rarely and are nearly 100% curable. An additional 130,000 skin cancers affect the pancake-shaped cells that form the skin's upper layers. Although highly treatable, these squamous-cell carcinomas grow faster than basal-cell tumors and annually kill 2,300 Americans. Malignant melanoma, which ravages the skin's pigment-producing cells, is the most unforgiving: it will strike twice as many Americans in 1993 as in 1980. Nearly 7,000 will die this year.

All the evidence gathered from animal experiments and epidemiological surveys points to the high-energy, shorter-wave ultraviolet-B portion of the sun's radiation as the main culprit in causing basal- and squamous-cell cancer. (Sunburns are also caused by UV-B radiation, wrinkles by the weaker UV-A part of the spectrum.) Since no animals other than humans and opossums suffer from malignant melanoma, researchers still do not know exactly what causes that more deadly disease. Most dermatologists have long assumed that sunburn-causing UV-B must be a greater threat than UV-A. As a result, sunscreen manufacturers originally concentrated on blocking UV-B. The most powerful formulas, developed in the past decade, have provided some protection from UV-A.