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Summer: the days are longer and the lakes are warming up but watch out for that sun. It can harm skin and increase the risk of skin cancer. 

The Canadian Dermatology Association notes that every week, 56 Ontarians are diagnosed with melanoma, a potentially deadly form of skin cancer. This year, the association says there will be an estimated 2,950 new cases of melanoma diagnosed in Ontario and 460 deaths.

Writer Paul Fraumeni spoke to Dr. Cheryl Rosen, head of the division of dermatology at the University Health Network’s Toronto Western Hospital and associate professor in the Faculty of Medicine at the 91�Թ� about the importance of protecting skin from the summer sun’s enticing – but dangerous – rays.

How does sunscreen work?

Sunscreens have compounds within them that absorb ultraviolet radiation. Most of them are chemicals that absorb ultraviolet A or B. Some of them have titanium dioxide and zinc oxide and while they absorb a little bit, mostly they work by reflecting the UV rays.

Why are there different SPF (Sun Protection Factor) levels?

What the SPF really tells you is the protection you will get against sunburn. That’s how sun screen is tested. Scientists use human volunteers to test sun screen, exposing very small areas of skin to ultraviolet radiation that is very similar to the output of the sun and they observe how subjects’ skin burns when they’re not protected compared to when they are protected with a standard dose of sunscreen and different amounts of ultraviolet radiation. So SPF only tells you about protection against sunburn.

There is a standardized amount for the testing, but in reality, people usually use far less sunscreen than they should. So you should use a liberal amount of sun screen to ensure you are getting the protection of the level that is indicated on the label. Because if you’re using a 30 but putting on very little, you’re not really getting an SPF of 30.

It is advisable to use a higher number of SPF, at least a 30. It has been proven that with a higher SPF, less UV is actually getting through to the skin.

Because the SPF test only tells you about a sunburn protection, it doesn’t tell us, really, about what number would be best to prevent skin cancer, or wrinkling, DNA damage, all the other end points caused by UV radiation. 

What about sunblock versus sunscreen?

No, we don’t call anything “sunblock” anymore. Nothing is perfect. The word “block” gives you the impression that it’s blocking out all the effects of the sun, but it’s not. It’s decreasing the amount that’s getting through but not totally blocking it. The FDA ruled in 2011 that in the U.S. you can’t call it a sunblock anymore. Also in the U.S., you can’t say “waterproof” or “sweatproof” anymore. You only say “resistant.” Health Canada hasn’t revised its guidelines for sunscreen, but it is in the process of doing that.

Can you be allergic to sun screen?

Yes, some people are allergic to certain ingredients in sunscreen. Given the amount of sunscreen that is out there, allergies are not common. There’s also something called “photoallergy” where you’re only allergic to a particular compound when you’re in contact with that compound as well as sunlight. At the dermatology clinic at Toronto Western Hospital, we do testing to determine if people have a photoallergy. This is called photopatch testing.

Have people heeded the call about wearing sunscreen in the summer?

The use has increased, but not as much as one would have hoped. We did a survey in 2006 across Canada and found that fewer Canadians that you might think use sunscreen on a regular basis. Certainly more people are using it than many years ago and there are a lot of products on the market now and those products are more consumer friendly now – they’re not as sticky or greasy. Still, our study showed that fewer than 50 per cent of Canadians use sunscreen on a regular basis.

Who doesn’t use it?

Mostly, it’s teenagers and, especially, young men.

Still, more people are using sunscreen than, say, 30 years ago. Have skin cancer rates decreased as a result?

We’re actually still seeing an increase in skin cancer rates. Public education has to be a priority because it has been proven to work. In Australia, where they have high rates of skin cancer, the government supported media promotion and public education about protecting your skin from the sun and the risk of  developing skin cancer. As a result, behaviour changed. People started using sunscreen more and using other forms of sun protection more often. Then when the government withdrew the funding, behaviour started to revert to unhealthy practices.

The spray sunscreen seems to be popular now. Does it work as well as the lotion?

The sprays are supposed to be tested just as the lotions are, using the same standardized testing protocol. So, theoretically, the spray should work as well as the lotion. But the issue is, as we said before, how do people use them? Sometimes people put the sunscreen on and forget to rub it around or they don’t spray evenly over their exposed skin. So, lotion or spray, it is important to use sunscreens correctly. Apply it liberally and evenly on your exposed skin and re-apply if you’re outdoors for a long time during the day.

Aside from sunscreen, what else should we do to protect our skin from the sun?

A few healthy practices:

• Wear a hat if you can
• Wear protective clothing, such as long sleeves and pants. I realize that can be hard in the warm weather, but if you’re going to be in the sun for prolonged periods of time, this can really help
• Plan your activities, such as sports or work, for earlier or later in the day versus the peak UV time from noon until about 2 in the afternoon
• When you can, stay in the shade.

Paul Fraumeni is a writer with the Univrersity of Toronto's Office of the Vice-President, Research and Innovation.