Avoiding Skin Cancer Risk with UV Protection

With summer arriving in full force in the US, and many families planning beach and other outdoor vacations, sunblock products move to front-and-center status.

The picture is often confusing. What does SPF 30 mean? Will this product keep me from getting a sunburn, or worse, skin cancer? Is this product really endorsed by a dermatologist? Perhaps the answers used to be simpler, but with the increase in skin cancer and other issues, the biggest question might be how much SPF—and how much overall protection—is enough?

The easiest way to explain SPF (the Sun Protection Factor used to measure levels of protection in the US) is to actually define what it means. The higher and SPF number in a product, the longer a person applying that product will be protected.

Say your patient burns in 20 minutes and applies a sunblock product with an SPF of 30—the lowest number recommended for protection—that person will be shielded from the sun’s burning (or UVB) rays for a total of 600 minutes. If the patient uses a product with a higher SPF factor (there are sunblocks with SPF factors as high as 70 and 85), that time will increase.

Yet, does that mean an active person can simply put on a sunblock, sit in the sun, and forget about it for the time the SPF offers protection? Not quite. If one sweats fairly heavily, perhaps in a game of tennis or beach volleyball, they must reapply. If they go swimming—some sunblocks claim to stay on in the water better than others—the safe course, especially if one towel dries, is to reapply.

Dermatologists and oncologists alike should also remind their patients to apply sunblock about 20 minutes before sun exposure to allow the blocking ingredients to settle into the skin. There are two types of sunblock available: most are chemical sublocks, containing elements such as Avobenzone (Parsol 1789), Oxybenzone, and Homosalate. PABA, which was used in sunscreens years ago, was removed as less-irritating products were developed. The others are physical sunblocks, containing minerals such as Titanium Oxide and Zinc Oxide. You may even recommend a product with a combination of both. Chemical sunblock works by blending into your skin and diffusing the sun’s rays, so to speak. Physical sunblocks prevent the sun’s rays from reaching your skin at all, thus difussing the skin cancer risk. Some people prefer the physical sublocks over their chemical counterparts.

Another matter to remember is that many of the elements in a chemical sunscreen begin breaking down when coming into contact with the sun’s UVA rays—which can cause skin cancer—and UVB rays, which are the ones that cause sunburn. The sun also emits UVC rays, but they do not get through the atmosphere to the ground.

Several companies have integrated a process into their chemical sunblocks to keep the elements from breaking down. This includes Neutrogena, which has included “Helioplex”; BullFrog, which has “Ultra Defense”; and Aveeno, which offers “Continuous Protection.” The manufacturer’s state their products gives users “continuous, broad-spectrum protection’’ against both UVA and UVB rays. This is where controversy has arisen of late.

SPF, it must be stated, is a factor that protects against UVB rays only. There has never been a rating in the US as far as what protection a sunblock gives against the UVA (or cancer-causing) rays. Avobenzone has been proven affective in blocking the UVA rays, as have both Titanium and Zinc Oxides in the physical sunblocks, but there has never been an actual rating like the European “Star’’ rankings of UVA protection.

Many—including the lobbyists Environmental Working Group (EWG), which issued a report earlier this week stating that many US sunblocks, according to their findings, are not providing buyers the protection promised—say that chemicals such as Oxybenzone can cause problems with allergies and hormones. The EWG stated in its investigation that “only 1-of-5 (sunblocks) provided adequate protection against both UVA and UVB radiation with a few ingredients linked to known or suspected health hazards.’’

Companies, especially Neutrogena, defended their products vs. the report, citing the rigorous testing they have undergone, their safety, and the endorsements they have received. Meanwhile, the FDA has been working on new packaging on sunblocks, rating products for both UVB protection via SPF and UVA protection using a system similar to that of the European Union, which will be appearing soon. The best recommendation you can provide to your patients is a wealth of sun-friendly information in order to effectively reduce their risk of skin cancer.