The power of sunscreens to protect against sunburn is well established. This is the feature of sunscreens identified as the Sun Protection Factor or SPF. Yet sunscreens allow people with fair skin to stay outdoors longer, often to get a tan or to maximize burn-free time in the sun. In the process, they are intensely exposed to UVA rays, which do not cause burning but inflict more subtle damage (Autier 2009, Lautenschlager 2007). Meanwhile, research findings conflict.
Skin cancer is the most common cancer in the United States, accounting for nearly half of all cases. The latest statistics raise questions about most effective ways to avoid skin cancer:
•More than two million Americans develop skin cancer each year (Bikle 2008, Rogers 2010, ACS 2010).
•Skin cancer is five times more prevalent in the U.S. population than breast or prostate cancers (Stern 2010).
Even though more people are using sunscreens than ever before, and products are improving in quality, the incidence of skin cancer in the United States and other countries continues to rise (Aceituno-Madera 2010, Jemal 2008, Osterlind 1992). In fact, a number of studies conducted in the 1990s reported higher, not lower, incidence of the deadliest form of skin cancer, malignant melanoma, among frequent sunscreen users (Autier 1998, Beitner 1990, Westerdahl 2000, Wolf 1998). But other studies suggest that sunscreens protect against melanoma (Autier 1995, Green 2010, Westerdahl 2000, Wolf 1994).
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