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22 Jun

Skin Cancer Prevention Q&A

Skin Cancer Prevention Q&A

It’s important to be aware of the cause of skin cancer and how best to protect yourself. Regular skin inspection and examination will aid in decreasing your likelihood of complications from skin cancer. With the summer months approaching, here are some answers to questions about prevention of common types of skin cancer.

 

What causes skin cancer?

Most skin cancer is caused by repeated exposure to ultraviolet radiation (UVR), which comes from the sun’s rays. Over time, UVR damages skin and can contribute to the development of premature wrinkling, age spots, and skin cancer. 

 

What kind of ultraviolet light do I need to worry about?

The two main types of ultraviolet light are UVA and UVB. UVB is thought to be the primary inducer of skin cancer, and is more responsible for causing sunburn. UVA is thought to enhance the damaging effects of UVB. It is important to protect against both types of UV light. 

 

How do I protect against UVA and UVB rays?

A sunscreen that effectively protects against UVA and UVB rays will say “Broad Spectrum” on the bottle. Non-Broad Spectrum sunscreens must contain the following warning: “Skin Cancer/Skin Aging Alert: Spending time in the sun increases your risk of skin cancer and early skin aging. This product has been shown only to help prevent sunburn, not skin cancer or early skin aging.”

 

So, what does SPF really mean?

SPF means Sun Protection Factor. SPF compares the amount of sun exposure a person will get with and without sunscreen. Using an SPF-10 sunscreen means it will take ten times as long for the effects of sun exposure to develop. For example, say it takes you 5 minutes to burn if you sit in direct sunlight; if you sat in direct sunlight with SPF 10 applied, it would take 50 minutes to burn. 

 

What strength of SPF should I choose?

According to the Food and Drug Administration (FDA), a product must be a broad-spectrum sunscreen with an SPF of 15 or more to be labeled as effective in decreasing the risk of skin cancer and early skin aging. Broad-spectrum sunscreens with an SPF of less than 15 may only be labeled as ‘sunburn protection’, and not as protective against skin cancer. 

SPF of various strengths differ in the amount of UVB rays they can block. An SPF of 15 provides about 93% UVB protection, an SPF of 30 provides about 96% UVB protection, and an SPF of 50 provides approximately 99.7% UVB Protection. Therefore, beyond an SPF of 50, there is really no additional benefit in terms of protection. 

 

How often should I apply sunscreen?

Apply sunscreen liberally to all exposed areas 15-30 minutes before going out into the sun. Make sure to reapply, after no more than 2 hours if sun exposure continues. If you are perspiring, in the water, or wipe an area with a towel, make sure to reapply sunscreen to affected areas. Water-resistant sunscreens may last longer, so be sure to follow directions on the container.

 

Is sunscreen necessary on cloudy days? 

Yes. Cloud cover does not protect you from ultraviolet rays. Depending on the thickness of cloud cover, an overcast day may protect you from approximately 10-30% of rays. This means that even on the cloudiest of days, 70% of the sun’s ultraviolet rays are still reaching your skin. How can this be, when some days are so cold and overcast? Infrared rays, which contribute to the sensation of heat that is felt from the sun, can be filtered out by cloud cover. 

 

Source: Crosby K. O’Neal K. Handbook of Nonprescription Drugs. 18th ed. Washington, DC: American Pharmacists Association; 2015.