UVB Rays Linked to Milder Skin Cancer
UVA May Be More Important Than UVB for Melanoma -- Best Bet to Avoid Both
UVA: The Bad Guy?
Part of that "something else" may be UVA sunlight. UVA rays penetrate deeper into the skin the UVB rays.
"People argue that UVA does play more of a role in melanoma for two reasons," Wei says. "One is that the ozone layer is depleted, so UVA radiation comes down more easily. The second is that early sunscreen products worked against UVB and UVC but not UVA. Later on they developed better ones. But that misled people to feel safer wearing the older products, so they got more exposure to UVA."
What all this means is that we should continue to avoid too much sun, says melanoma expert Marianne Berwick, PhD, director of the cancer epidemiology and prevention in cancer center at the University of New Mexico, Albuquerque.
"Wei's team reports a really intriguing finding, but it does not mean a thing yet for the public," Berwick tells WebMD. "People should definitely continue to avoid intense sunlight, especially the kind that they get on vacation and on the beach. Those are the exposures that are most damaging for melanoma. Even though the early-life exposure is much more of a risk, later-life sun exposure is also a risk. So enjoy the sun -- just not in huge doses."
Wei warns that his study does not give UVB rays a clean bill of health.
"UVB is dangerous. The DNA damage it causes is lethal," he says. "UVB causes a lot of DNA damage you cannot see with the eyeball or even with the microscope. It is like smoking and lung cancer. Nothing can help if you continue to smoke. With sun, it is the same thing. Don't continue to expose yourself."
Wei says it's important to read the label on sunscreen products. He says consumers should look for products that offer protection against all forms of ultraviolet light: UVA, UVB, and UVC.