Special Report: Skin Cancer

By LEON JAROFF

It was a hot July day in Amagansett, N.Y., and the noonday sun glared down at a crowded Long Island beach. Perched atop his observation stand, a bronzed lifeguard, hatless and clad only in abbreviated trunks, kept close watch on the few dozen waders and swimmers braving the still frigid waters of the Atlantic Ocean. Around him, hundreds of sunbathers sprawled on the sand. Some, mostly older, shielded themselves from the sun's fierce rays under broad- brimmed hats and umbrellas. But much of the crowd baked contentedly in the sunlight, wearing only scanty swimsuits and little or no sunscreen. At the water's edge, tots played in the sand, some with backs and arms alarmingly red.

Across the U.S. last week, this scene was repeated as millions of people, still unaware of the odds against them, continued to play a game of solar roulette. Those odds are worsening at an alarming rate. The American Cancer Society predicts that in the U.S. this year, more than 600,000 new cases of skin malignancies will be diagnosed, most of them caused by excessive exposure to ultraviolet rays from the sun. Some 27,600 of those cases will be malignant melanoma, the deadliest type, which has been increasing 7% annually over the past decade and will kill 6,300 people this year. Most of the other skin cancers will be basal-cell and squamous-cell carcinomas, less lethal but still dangerous if not treated in time. Some 2,500 victims of these cancers (mostly squamous cell) will die this year, and most of the others will undergo surgery, generally minor but occasionally disfiguring.

Doctors are particularly struck by the rise in melanoma cases. "When I went into practice 25 years ago," says Dr. Henriette Abel, "if I saw one melanoma a year, it was a big deal." This year, however, "there was a period when I saw six in six weeks." Her brother Dr. Robert Abel, with whom she shares a dermatology practice in Elizabeth, N.J., now diagnoses an average of one melanoma case a month.

Experts attribute the growing onslaught of skin cancer to the new affluence of Americans in the years after World War II. That was when they began taking vacations in the Sunbelt and the Caribbean; adopting the sun-worshiping culture, as well as the music, of the Beach Boys; and jogging endlessly in skimpy clothes. Because the effects of sunlight on the skin are cumulative and usually require years of exposure before malignancy begins, the results are just showing up now. The Harvard Medical School Health Letter has neatly summarized the situation: "The bronzed youth of the baby boom, now reaching middle age, are in the vanguard of the melanoma plague."

Greater danger may lie ahead. Some have suggested that depletion of the ozone layer, which blocks much of the sun's ultraviolet radiation, is contributing to the rise in skin cancer. While there is little evidence to support this notion, scientists agree that in the long run a diminished ozone layer will cause trouble. "Decreased ozone will increase numbers of basal- and squamous-cell carcinomas," says Dr. Stanford Lamberg, a Johns Hopkins dermatologist. "There is no question about that."

The skin's dynamic outer layer, or epidermis, serves as the staging ground for all three of the major skin cancers. Both basal-cell and squamous-cell carcinomas arise from the most common skin cells, the keratinocytes, which form at the base of the epidermis and work their way toward the surface. Near the base, they are plump and are called basal cells. But as they move outward, they flatten to become the squamous cells that form the skin's tough, protective surface. Melanomas spring from melanocytes, cells that produce pigment.

Epidermal cells become malignant when the DNA in their nuclei is altered, causing them to divide uncontrollably and form tumors. The transformation of DNA can be caused by repeated X-ray exposure, burns, infectious disease or frequent contact with certain chemicals. But by far the most common culprit is the sun's ultraviolet light. After years of exposure to sunlight, the damage becomes visible first as small, scaly, precancerous spots called keratoses, usually on middle-aged or older people and in areas of the skin generally not protected by clothing. These spots can turn malignant, becoming translucent basal-cell nodules that slowly expand into adjoining tissue.

Unlike other cancers, basal-cell carcinomas rarely metastasize, or migrate to form tumors in other parts of the body. For that reason, many people regard these carcinomas lightly and unwisely put off corrective surgery. Doctors excising basal tumors that have gone too long without treatment must often remove large chunks of their patients' noses or ears, which then must be reconstructed surgically. Worse consequences can occur. "I've heard of only a few deaths due to basal-cell carcinomas," says Dr. Lamberg. "But if an unattended tumor on the head grew into the brain, for example, it could cause considerable damage or even death."

Squamous-cell carcinomas also develop from keratoses on long-exposed areas of the skin, affecting about 100,000 Americans each year. They take the form of red or pink warty growths that may scale or open in the center and ooze. Squamous tumors are more dangerous than basals; they grow more rapidly and can metastasize, sometimes with fatal results.

But by far the most fearsome form of skin cancer is malignant melanoma, which sometimes emerges from an existing mole or simply appears in an area of previously unblemished skin. Melanomas are asymmetrically shaped, usually begin as mottled light brown or black blotches that eventually can turn red, white or blue in spots, become crusty and bleed. They grow rapidly, and once they have expanded to about the thickness of a dime, they have probably metastasized and become lethal.

Here too the sun's ultraviolet radiation plays a role, but apparently a different one. Many melanoma victims have had three or more episodes of severe sunburn and blistering, usually as children or teenagers. Those experiences seem to set off a still mysterious process that results in the development of melanomas years later, often on parts of the body seldom exposed to the sun. Some evidence also exists that heredity plays a more important role in melanoma than in other skin cancers.

In general, those most vulnerable to skin cancer are the light-skinned, light-eyed people of north European extraction, particularly those with red or blond hair and freckled skin that reddens and burns easily, blisters and peels. Caucasians with dark hair and eyes and more even pigmentation, as well as Hispanics and Asians, are somewhat less susceptible, and blacks rarely develop either carcinomas or melanomas. The rate of melanoma among blacks, while increasing, is only one-fiftieth that of whites.

Dark pigmentation is obviously protective. The rare melanomas found among blacks develop almost exclusively in areas of lighter skin not usually exposed to the sun: palms of the hands, soles of the feet, under fingernails and even in the mouth. This leads experts to believe that melanomas among blacks are largely genetic.

Geography also plays a role in skin cancer. Equatorial regions, where the midday sun beams down from directly overhead, receive the most intense ultraviolet radiation. Farther north or south, solar rays strike the earth at a more oblique angle, taking a longer passage through the atmosphere, where the ozone layer absorbs more of the ultraviolet light before it can reach the surface.

Skin-cancer statistics vary accordingly. For example, the National Cancer Institute reports that from 1983 to 1987, Atlanta's melanoma rate averaged 11.6 per 100,000 people each year, while the more northerly Detroit's average was only 7.4. In Tucson, Ariz., which is close to Atlanta in latitude but has many more sunny days, the rate soars to 19, the highest in the U.S.

The migration to tropical climes of people with racial origins in higher, less sunny latitudes has also led to rising rates of skin cancer. A survey of nonmelanoma skin cancers in Hawaii, for example, concluded that Japanese residents of the island of Kauai were 88 times more likely to develop a skin malignancy than Japanese living in Japan. And in subtropical Australia, which was settled largely by the fair-skinned English and Irish, the skin-cancer rate is the highest in the world. Two out of three Australians will develop at least one skin cancer during their lifetime.

That remarkable statistic helps explain why Australia is a leader in anti- skin cancer campaigns. Each year during National Skin Cancer Awareness Week, literature and posters are distributed and dermatologists conduct free skin-cancer screenings. In the state of Victoria, lifeguards are used as role models. They sit in shaded areas, pass out skin-cancer literature, don hats and wear T shirts emblazoned with the slogan SLIP! SLOP! SLAP! -- which practically everyone Down Under understands to mean "Slip on a shirt. Slop on some sunscreen. Slap on a hat."

Awareness of skin cancer is rising in the U.S., largely through the efforts of the Skin Cancer Foundation and the American Cancer Society, which attempt to spread the word through posters, pamphlets, newspaper ads and an occasional billboard. Hollywood may help. Some of today's most popular female stars, including Kim Basinger and Geena Davis, shun the sun, projecting a pale beauty that could influence a new generation. Manufacturers of sunscreens seem to have caught on. Store shelves these days display more screens with sun- protection factors of 15, 25 and 30 than with the once familiar 4 and 8 ratings.

Applying a screen with an SPF of 15, for example, wards off reddening of the skin 15 times longer than would be the case without any protection. That would seem long enough, and some dermatologists have suggested that using higher SPFs is unnecessary. But Dr. Kays Kaidbey, a dermatologist at the University of Pennsylvania, has found that microscopic changes occur in the skin even when sunburn has been prevented. Writing in the Journal of the American Academy of Dermatology, Kaidbey reported that screens with SPFs of 30 are more effective than those with 15 ratings in preventing those changes.

Despite the growing publicity about skin cancer and sunscreens, untold numbers of Americans have either missed or are ignoring the message and are still exposing themselves needlessly to the sun. A glaring example: the San Francisco Bay Guardian, a weekly newspaper that annually publishes a list of Northern California nude beaches, proudly revealed last month that its listing had grown from 21 beaches in 1976 to 69 this year. Other Americans continue to sunbathe wearing next to nothing. "Our society has placed an enormous value on being tan, equating it with health, youth, beauty and success," says Dr. Susan Blumenthal, chief of the National Institute of Mental Health's behavioral medicine program. "It will take at least a couple more years before we see a drastic change in societal attitudes about tanning."

Probably longer. Tanning parlors are still much in vogue in the U.S., and many owners boast that their lamps generate mainly long-wave ultraviolet-A rays rather than the shorter-wave UVB rays that are known to cause sunburn and basal- and squamous-cell carcinomas. But Dr. John DiGiovanna, a National Cancer Institute dermatologist, insists that UVA, which penetrates deeper into the skin than UVB, causes cancer. Its role, he says, "simply hasn't been as widely recognized as UVB's because its intensity in solar radiation is much less than UVB's." He asks, "Who knows what will happen in these tanning booths? People have never been exposed to such high doses of UVA before." Dr. Laurence David, a Hermosa Beach, Calif., dermatologist, is more vehement. "Tanning parlors are carcinogenic," he charges. "We've got to get this George Hamilton look out of our minds." That may be difficult. "Young people are continuing to use tanning parlors," says an East Coast dermatologist. "They are simply guaranteeing my future income."

Dermatologists are busy enough today, excising keratoses and skin tumors by surgery, freezing them, burning them out with an electric needle or bombarding them with radiation or laser beams. Once a skin tumor has metastasized, however, modern medicine is still largely stymied. When a malignant melanoma has reached that stage, for example, the victim's survival rate drops to below 10%. "The best way to treat skin cancer is to remove the tumors before they * spread," says Steven Rosenberg, chief of surgery at the National Cancer Institute. Conventional cancer treatments -- surgery, chemotherapy and radiation -- are largely ineffective against advanced melanoma, he says. But Rosenberg has had some success with a fourth, still unconventional treatment. He calls it "biological therapy," a strategy for spurring the body's immune system to attack and destroy the malignant cells.

One Rosenberg technique, used in dozens of U.S. cancer centers, is to extract some of a patient's white blood cells and bathe them in interleukin-2, a hormone that stimulates them, turning them into lymphokine-activated killer, or LAK, cells. Injected back into the bloodstream along with repeated doses of interleukin-2, they attack any foreign cells (including malignant ones) with great vigor. The technique has caused tumors to shrink significantly in a number of advanced melanoma patients and has apparently even effected an occasional cure.

A more advanced technique proposed by Rosenberg involves a human gene that orders production of a tumor-killing chemical. This gene would be inserted into an extracted immune cell called a tumor-infiltrating lymphocyte. Injected back into the body, the engineered TIL cells would specifically seek out and destroy melanoma cells.

Still, whatever progress is made during the next few years in fighting skin cancer, the best therapy will remain prevention, especially in childhood and the teens, when most of the damage is done. To Americans long indoctrinated with the notion that a tan look is a healthy look, this means that instead of worshiping the sun, they had better begin respecting it.

With reporting by Jonathan Beaty/Los Angeles and Rosanne Spector/Washington