Daily use of sunscreen really is best
By Jane E. Allen
Los Angeles Times
Applying sunscreen every day, rain or shine, is a more effective way of protecting against skin cancer than slathering it on occasionally when heading to the beach, park or swimming pool, a new study has found.
Doctors have long advocated daily use of sunscreen, especially for people living in sunny climates, because it more consistently shields the skin against damaging sun exposure that can lead to skin cancer. But getting people to use sunscreen every morning is about as easy as getting them to eat five servings of fruits and vegetables.
The study, by researchers in Australia, is the first to establish the value of daily sunscreen use by tracking how people applied it for several years.
Rates of skin cancer are rising worldwide, and the sun's damaging UV rays don't reach your skin just when you're lying on a beach or playing tennis. Brief, intermittent exposure, such as when taking a lunchtime stroll or when schoolchildren play during outdoor recess, requires protection, too. That's because skin cancer results from cumulative exposure.
Anyone who is at risk for skin cancer, especially people with fair skin, light hair and blue-green eyes — but even those living in northern regions where the sun isn't as strong — should make sunscreen use a routine, says Dr. David J. Leffell, a Yale University dermatologist. "The barrier is still the human one — remembering to do it."
The Australian study, published in the April issue of the Archives of Dermatology, focused on the development of precancerous sun spots called actinic keratoses. These signs of sun damage contain abnormal cells and can appear as rough and sometimes red or pink spots and patches. People who have them are up to 12 times more likely to develop two common types of skin cancer: basal cell carcinoma and squamous cell carcinoma. Doctors remove actinic keratoses because a small percentage of them will develop into more dangerous squamous-cell carcinomas.
By demonstrating that daily sunscreen use reduces the incidence of actinic keratoses "and, by inference, the cancers that develop from them," the Australian study should help boost a new campaign to reduce skin cancer rates by protecting children's skin, Leffell said. The campaign advises shielding kids from the sun with hats and sunscreens that can be applied beginning at 6 months of age, Leffell said.
The Australian researchers compared people who liberally applied a water-resistant SPF-16 sunscreen cream every morning to the head, neck, arms and hands with others who only used sunscreen when they thought they needed it.
The four-year study tracked development of actinic keratoses on the skin of 1,621 study volunteers, ages 25 to 74. The regular sunscreen users had 24 percent fewer pre-cancers than intermittent users after the first 2 1/2 years of the study. In some cases, the sunscreen prevented formation of new lesions; in other cases sunscreen appeared to reverse existing ones.
"The study indicates yet again the great potential value of sunscreen application, when undertaken conscientiously and carefully, against the now extremely well documented ravages of sunlight in both the short and long term," wrote Dr. John L. M. Hawk, a dermatologist with St. Thomas' Hospital in London, in an editorial accompanying the study.
