TIME: Almanac 1993/TIME Almanac 1993.iso/time/072390/0723350.000

Text File | 1992-08-28 | 15.9 KB | 347 lines

                r                                                              MEDICINE, Page 68

Special Report: Skin Cancer

The Dark Side of Worshiping the Sun


Americans are flocking to the beaches by the millions this
summer, many still blissfully unaware that if they fry now,
they could pay later -- in the form of tumors

By LEON JAROFF -- Reported by Jonathan Beaty/Los Angeles and
Rosanne Spector/Washington


    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.


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ASSAULT ON THE SKIN


    Ultraviolet A

    This long-wave length constituent of sunlight causes aging
of the skin, tanning and sometimes sunburn. It penetrates
deeply and may contribute to skin cancer.

    Ultraviolet B

    Abundant in sunlight, this shorter-wave radiation causes
sunburn, premature aging and wrinkling. It is largely
responsible for basal- and squamous-cell carcinomas, and plays
a role in malignant melanoma.

    Melanoma

    This deadliest of skin cancers invloves melanocyte cells,
which produce pigment. It can develop from a mole or on
unblemished skin, grows quickly, and can metastasize.

    Basal-Cell Carcinoma

    The most common skin malignancy is usually caused by
excessive sun exposure. It develops slowly, rarely
metastasizes, and is nearly 100% curable if diagnosed early and
treated properly.

    Squamous-Cell Carcinoma

    Arising from cells in the upper layer of the epidermis, this
cancer, also caused by UV rays, is usually curable if treated
early. It grows faster than basal-cell carcinoma and can
metastasize.