We have been taught to slap on sunscreen to prevent skin cancer. Recently I have come upon a number of references suggesting that our commonly used sunscreens may not be effective at all in preventing melanoma but only in preventing more common but also more benign and treatable skin cancer. Is this true? If so, who is behind the sunscreen lobby? Thanks in advance for letting your light shine on this. –David de Graaf
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Little late in the summer to be bringing this up, but maybe now you’ll have something to read in the waiting room at the cancer specialist’s. The scariest version of this story is that sunscreen increases your chances of getting cancer. More on that in a mo. First let’s answer your question. There’s no hard evidence that sunscreen prevents melanoma, the least common but most dangerous skin cancer (42,000 cases per year, and 7,000 deaths), or even basal cell carcinoma, the most common, least dangerous cancer (600,000 cases a year, rarely fatal). Sunscreen prevents sunburn and possibly squamous cell carcinoma (200,000 cases, perhaps 2,000 deaths). More than that we just don’t know.
Berwick took a lot of heat, but most of it was harrumphing by guys who didn’t like her calling their bluff. Fact is, we don’t know much about the causes of melanoma, mainly because of a lack of “animal models” to study–few suitable lab animals get skin cancer solely due to UV exposure, as humans seem to. Because of that, we can’t offer much in the way of definitive statements or useful advice. Having spoken to Berwick and to Frank Gasparro, a dermatology professor and sunscreen expert at Thomas Jefferson University in Philadelphia, I can offer only these crumbs:
Check out sunscreens containing zinc oxide, titanium dioxide, or avobenzone. Though not easy to come by, these are among the few commercially available ingredients known to protect against UV-A. Which doesn’t necessarily cause melanoma, I hasten to say, but might. When we know so little about skin cancer, no sense leaving anything to chance.
