Bring Back the Parasol

By Claudia Wallis

With summer just around the corner, the pale of face throughout the Northern Hemisphere will soon be hitting beaches in pursuit of a deep, dark and sexy tan. The Victorian ideal of delicate, camellia-white skin has long since been supplanted by the bronzed-god look. But the trend has taken a mortal toll. Sun-related skin cancer is rapidly on the rise in the U.S. and Europe, and afflicting younger and younger people. The incidence of the most lethal form, malignant melanoma, though less directly linked to sunshine, has jumped tenfold in the past 20 years. Last week some 300 dermatologists and others gathered in Manhattan to discuss the problem at the first World Congress on Cancers of the Skin. Their message: bring back the parasol.

Doctors have long known that ultraviolet (UV) radiation from the sun produces profound changes in human skin. "Even one day's exposure can cause damage," says Dermatologist Fred Urbach of Temple University in Philadelphia. The most insidious rays are the short wavelength UVB, which prevail during the peak sun hours (between 11 a.m. and 3 p.m.). But new research has shown that even longer UVA waves, which are present all day, can promote skin cancer.

The damage caused by these invisible rays ranges from ordinary sunburn, to the wrinkles and liver spots caused by years of sunbathing, to the precancerous dark patches known as actinic keratosis and, finally, cancer. Each of these is part of the same process, says Urbach. "First you look old, then if you've had a lot more sun, you get keratosis, and after that skin cancer. If we all lived long enough, we would all get skin cancer."

The process begins when solar UV damages basal cells near the surface of the skin, causing them to swell. The pain and redness, which appear a few hours after exposure, are caused by the dilation of blood vessels in the damaged area. The ensuing tan is the body's desperate effort to save its skin from further injury. Tiny granules of melanin, a brownish pigment made in specialized skin cells, rise to the surface in response to UV radiation and act as sunlight deflectors. Over the years, however, the beachgoer pays for this glamorous natural shield. The buildup of melanin, combined with UV damage to the elastic fibers in underlying layers, gives the skin the texture of an old baseball mitt.

Ultraviolet radiation has less obvious but even more pernicious effects. By altering proteins in the lens of the eye, it causes a gradual deposit of yellowish pigment. As with the tan, this pigmentation is beneficial up to a point; it helps shield the delicate retina from UV damage. But the dense accumulation of pigment after years of sunning is the main cause of cataracts.

Like X rays, UV radiation can alter cell DNA, producing the mutations associated with cancer. "Both UVA and UVB are carcinogenic," says Harvard Photobiologist Madhu Pathak. UV also appears to suppress the body's immune system. This may explain why certain viral infections, such as chicken pox and fever blisters, become more severe in the sun. And since the immune system is believed to play a role in preventing tumor growth, its suppression "may also be an aggravating factor in the development of skin cancer," says Dr. Margaret Kripke of the National Cancer Institute.

About 80% of the skin cancers caused by the sun are basal-cell carcinoma. Usually occurring on the head or neck, they are the most common and curable form of cancer in the U.S. Nancy Reagan was one of 400,000 Americans treated for this disease last year; she has more recently had several spots of keratosis removed from her face to prevent a recurrence. Skin cancers that appear elsewhere on the body are usually squamous-cell carcinoma, also easily cured by surgery.

Far more lethal are the darkly pigmented spots of malignant melanoma, which strikes more than 15,000 Americans a year, killing 45% of them. Though melanoma tends to occur on such sun-exposed areas as the chests of men and legs of women, its relationship to the sun remains unclear. A history of severe sunburns may play a role; pregnancy and birth control pills have also been implicated.

The evils of ultraviolet are easily escaped. Mrs. Reagan had the right ideas when she resolved last New Year's Day to stay out of the sun. For those unwilling to make that sacrifice, the doctors at last week's conference urged the use of sunscreen lotions, some of which are now formulated to block both UVA and UVB. The Food and Drug Administration has published guidelines recommending a sunscreen of certain strength for each type of skin. For fair skinned people who never tan and always burn (Type I skin), sunscreens labeled with the number 15 are best. The number indicates that it will take at least 15 times longer to burn when the product is used than when the skin is unprotected. People who sometimes burn and never tan should use sun screens in the 6-to-8 range; those who occasionally burn but tan well need only 4-to-8 protection; olive-complected Type IVs, who never get scorched, can manage with a factor of 2 to 4. In the future, however, a sunscreen pill being developed in Pathak's lab may make the lotions obsolete.

A number of doctors at the conference urged year-round use of sunscreens; several admitted they had rubbed some on that morning, even though they would be indoors most of the day. But the most urgent and unanimous recommendation was to protect the skin of young children. Though skin cancer may not show up until age 50, the initial damage is done in early childhood, says Dermatologist Isaac Willis of Morehouse School of Medicine in Atlanta. Indeed, most of a life time's sun exposure takes place by age 30. By the time wrinkles appear, the damage is done. -- By Claudia Wallis.

Reported by Mary Carpenter/New York

With reporting by Mary Carpenter/New York This file is automatically generated by a robot program, so viewer discretion is required.