Scientist Unconvinced That Sunscreen Prevents Cancer
A provocative presentation at a science conference Tuesday questioned the widely held belief that sunscreens lower the risk of deadly melanoma skin cancer, but specialists still caution against going into the sunshine without these lotions.
Sunscreens prevent sunburn, and since there is evidence that frequent burns, especially at an early age, trigger melanoma, many experts assume that using them should help ward off the cancer.
However, melanoma cases have risen dramatically over the last 25 years, even as sunscreen use became more common. The lethal cancer now strikes about 42,000 Americans a year, killing 7,300.
Dr. Marianne Berwick, an epidemiologist at Memorial Sloan-Kettering Cancer Center in New York City, said her own study, as well as a review of other research, offers no convincing evidence that using sunscreens keeps people from getting melanoma.
Ten studies have looked at the question, she said at the American Assn. for the Advancement of Science meeting. Three of them, including her own, found no link between sunscreens and melanoma. Two suggested that sunscreens seem to prevent it.
The five others found that melanoma risk actually increased among sunscreen users, probably because people who use them most are already at highest risk because of light complexions.
Several dermatologists strongly disagreed with Berwick’s report.
Until there is clear proof that sunscreens are ineffective, “it would be irresponsible to discontinue all recommendations about using sunscreens,” said Dr. Darrell Rigel of New York University.
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Dr. Michael Thun, director of analytics epidemiology at the American Cancer Society, said: “People should not stop using sunscreen because of this study.”
Melanoma may take 20 years or more to develop after excessive sun exposure. Some doctors argue that it is simply too soon to prove that sunscreens are helping, since No. 15 and stronger sunscreens have only been in wide use since the mid-1980s.
Still, doctors cautioned against using sunscreen as an excuse to bake in the sun. They said people at high risk of melanoma should avoid prolonged sun exposure, stay out of the midday sun and wear hats and long-sleeve shirts.
