ANAHEIM-The FDA has a weather eye on sunscreens for carcinogenicity.
The agency says it's taking seriously a report that one combination of the 21 allowed sunscreen products has caused lesions that weren't previously seen with the individual agents. The FDA's Dr. Javier Avalos told the Society of Toxicology meeting here that concerns include both basal-cell car-cinoma and melanoma.
In a study of young hairless mice treated for 13 weeks with a product containing a combination of four approved sunscreen products, but not exposed to UV light, there were "unexpected neoplastic effects," says Dr. Avalos. No such lesions were seen in 379 untreated mice.
In addition to sunscreen agents, the FDA is also concerned about photocarcinogenicity of other topical drugs such as photosensitizers, irritants, de-differentiators, and immunosuppressants, says Dr. Avalos.
"The potential photocarcinogenicity of topical drugs is an increasing concern at the FDA," he says.
Most commonly used in sunscreens are cinnamates, benzophenones, PABA derivatives, and salicylates. Various investigators, he says, have found p-methoxymethylcinnamate cytotoxic to certain cells in UV-A light, and the sunscreen padimate O mutagenic to yeast cells in UV-A.
Though some agents have been extensively evaluated individually, studies of long-term effects of sunscreen combos are rare, says Dr. Avalos. Many of the brands on the market have three or more agents. -Elsie Rosner
ANAHEIM-The FDA has a weather eye on sunscreens for carcinogenicity.
