Dermatologist susses sunscreen cancer risk

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Since last July the U.S. Food and Drug Administration has had data from studies examining a potential correlation between retinyl palmitate, a common chemical in sunscreen, and elevated cancer risk in lab rats, the agency has been slow to interpret the findings and offer guidance to the public, charges Senator Charles Schumer (D-NY). With beach season upon us, Schumer calls on the FDA to examine the available data and advise the public on the best way to reduce cancer risk. To learn more about what these initial findings mean for you — and your sunscreen habits — TIME spoke with Sacramento-based dermatologist Dr. Margaret Parsons.

Retinyl palmitate is a vitamin A compound in the same family as retin-A, which is known for its anti-aging applications. Studies conducted by the National Center for Toxicological Research and the National Toxicology Program found that lab rats whose skin was coated with a cream containing the chemical tended to develop tumors faster — 11% to 21% faster — than rats coated in a cream that didn’t include that ingredient.

While the FDA may not have yet offered any guidelines based on the findings, in its 2010 sunscreen guide, the non-profit Environmental Working Group recommends avoiding creams that include retinyl palmitate as well as oxybenzone, which they suggest is a “potential hormone disruptor.” (Of some 500 sun block products reviewed by the non-profit, only 8% met its top safety criteria.)

Yet even as criticisms of the vast majority of products currently on the market spur debate about the dangers of sunscreen ingredients, dermatologists are increasingly wary that inflating initial findings from animal studies could deter people from using sun protection altogether. Dr. Parsons points to clinical evidence suggesting that sunscreen reduces skin cancer risk. “We have years of sunscreen clearly decreasing cancer and we know that it’s an effective protection against cancer,” she says.”

Parsons agreed that additional research into the potential risks of retinyl palmitate is warranted, but warns against jumping too quickly from animal studies to human impact. “To extrapolate to humans is not realistic at this point,” she says. What’s more, in dermatology alone there are clear examples of differences between the way a chemical impacts animals in the lab, and its effect on humans, she says. One such example is benzoyl peroxide, a common ingredient in acne treatments. Research has shown that if you put enough of the compound on lab rats, it can work as a carcinogenic agent, Parsons says. Yet people use the chemical safely to treat acne all the time.

In a statement released at the end of May, Dr. William James, president of the American Academy of Dermatology (AAD), clarified that the active ingredients in sunscreen are regulated by the FDA and that the agency is currently considering labeling changes. Tentatively, that decision is expected in October, James writes. And while the AAD will continue to monitor developing science in this area, they continue to encourage the routine use of sun block as part of a skin protection regime. James writes:

“Scientific evidence supports the beneficial effects of sunscreen usage when used as one component of a daily photoprotection regimen. Sunscreen is an important tool in the fight against skin cancer. To prevent skin damage from the sun’s harmful ultraviolet rays, dermatologists recommend generously applying a water-resistant broad-spectrum sunscreen of an SPF 30 in conjunction with wearing protective clothing and seeking shade… Unprotected sun exposure is the most preventable risk factor for skin cancer, including melanoma. More than 1 million new cases of skin cancer will be diagnosed in the United States this year.”

Parsons said she would like to see additional research — examining the impact of different volumes and concentrations of retinyl palmitate specifically in humans — but believes that, currently, “there is not enough science to suggest that this is health concern.” Meanwhile, studies suggesting a link between sunburn and an increased risk for melanoma, should provide ample motivation to protect your skin from excessive sun exposure.

Whatever ultimately results from future study of specific ingredients in sunscreen, Parson emphasizes the importance of protecting your skin in a way that works for you — whether you opt for long sleeved shirts, hats and zinc oxide or popular sun block lotions that may contain retinyl palmitate. Based on the evidence available, Parsons says there’s no reason to assume that it currently poses a health hazard for the public. “I’m not ready in any way to make a drastic change,” she concludes. “My message is still this: Wear your sunscreen.”

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