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Skin Cancer Prevention: The ABCs of SPFs

May 1, 2017

Skin Cancer Prevention - What you should know about Sunscreen SPFMany people have a dangerous view about skin cancer. They incorrectly believe that developing skin cancer isn't really a big deal because if they do develop it, a dermatologist can simply cut it out. And, with some types of skin cancer (non-cancerous basal cell carcinoma) that's somewhat true.

However, another type of skin cancer, called melanoma, is cancerous. If melanoma isn't discovered and treated in the early stages, it can quickly spread to other parts of the body, becoming invasive. Invasive melanomas kill an estimated 76,000+ Americans each year.

Skin Cancer Can be Deadly, But it Can Also Be Prevented

By far, the number one cause of skin cancer is exposure to ultraviolet (UV) rays from the sun. The most effective ways to avoid UV exposure are by staying indoors and wearing clothing that covers all of your skin when you're outside. When coming in contact with the sun is unavoidable, wearing sunscreen is the number one way to prevent skin cancer. If you've ever encountered the sunscreen aisle in any store, you're aware of the huge selection of sunscreen options available, and you may have found yourself asking "What's the most effective sunscreen?" The more you understand the words and abbreviations on the labels, the better equipped you'll be to make a smart purchasing decision.

What Does SPF Measure?

There are two damaging types of UV rays: UVA and UVB. UVB radiation is responsible for causing sunburns. UVA radiation penetrates deeper into the skin and causes problems like wrinkles, leathery skin and sagging skin. The SPF (sun protection factor) label on sunscreen measures how well that sunscreen protects against UVB rays. SPF numbers refer to how much longer it will take your skin to burn with that sunscreen than without any sunscreen. For example, if your unprotected skin begins to burn in 10 minutes, wearing an SPF 15 sunscreen would prevent it from burning 15 times longer (approximately 2.5 hours).

Which SPF is Best?

At minimum, use a sunscreen with an SPF of at least 15. If you plan to be out in very intense sun and/or for long periods, a sunscreen rated SPF 30 does provide additional protection from harmful UVB rays. You might assume that an SPF 30 sunscreen would be twice as effective as an SPF 15 sunscreen, but that is not the case! SPF 30 sunscreen provides only "slightly" more protection than an SPF 15 sunscreen and the benefits decrease the higher the SPF number becomes. Specifically,

  • An SPF 15 sunscreen filters about 93% of UVB rays,
  • An SPF 30 sunscreen filters about 97% of UVB rays, and
  • An SPF 50 sunscreen filters about 98% of UVB rays.

According to the U.S. Food and Drug Administration (FDA), any SPF higher than 50 is "inherently misleading." The Australian counterpart to the FDA caps limits at SPF 30 and in Canada, the highest SPF claim allowed on a sunscreen label is SPF 50+.

While the marginally increased protection between and SPF 15 and an SPF 30 or 50 may make a difference in individuals with a history of skin cancer or who are unusually sensitive to sunlight, most experts agree that an SPF 15 sunscreen is adequate for most people - as long as it is applied properly.

Sunscreen Do's

To protect yourself from skin cancer, wear a sunscreen of SPF 15 daily. Your skin can be damaged simply walking from your car to your home or office. Choose sunscreens labeled "broad-spectrum," which filter both UVB and UVA rays.

Most importantly, apply enough sunscreen. According to the American Academy of Dermatology, most people use only 25% to 50% of the recommended amount of sunscreen. As a rule of thumb, the Academy recommends applying one ounce of sunscreen "enough to fill a shot glass." Reapply every couple of hours, more often if you're sweating or swimming. 

If you notice any changes of your skin, it is best to visit your doctor or dermatologist. If you do not have a current provider and are located in the Maryland or Washington D.C. areas, Maryland Oncology Hematology is available to meet with you and answer any questions that you may have about possible skin cancer. 

 

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Topics: Cancer Prevention, Skin Cancer