There is no question most skin cancers are related to sun exposure, yet even with sunscreen sales approaching $1 billion a year, skin cancer rates continue to climb.Melanoma diagnoses have risen nearly 2 percent a year since 2000 and are increasing even more among young white women.
Some experts blame inappropriate use of sunscreen, saying that people do not apply enough lotion (a golfball-size dollop) or do not reapply it every two hours as instructed. But there’s another major concern: Until recently, many sunscreens with a high sun protection factor, or SPF, were designed primarily to protect people from ultraviolet B rays, the main cause of sunburn. These sunscreens may have enabled users to stay out longer but did not necessarily protect them from ultraviolet A rays. These are associated with aging and skin damage, but some experts believe they may also be implicated in skin cancer.