Skin cancer is the uncontrolled growth of abnormal skin cells, and it’s the most prevalent form of all cancers in Canada.
“The good news is there are plenty of ways you can protect yourself,” says Dr. Harvey Lui, a dermatologist at the BC Cancer Agency. “The bad news is that there are quite a few misconceptions about sun protection that prevent people from taking necessary precautions.”
Here are five popular myths about sun protection, along with some simple things you can do to keep your skin out of trouble.
You may have heard rumours that sunscreen can actually cause cancer or other health problems. In particular, some media has reported concern with ingredients oxybenzone, a synthetic estrogen, and retinyl palmitate, a form of vitamin A stored by the skin.
“We should put this myth to rest right away,” insists Dr. Lui, “there is no evidence that approved sunscreens cause cancer or other health problems. In fact, the opposite is true: not wearing sunscreen is proven to pose a significant cancer risk.”
Much of the concern about oxybenzone stems from a 2001 study with rats fed over 1,500mg of oxybenzone per kilogram per day.
“That amount is astronomically high,” says Dr. Lui. “This is not clinically relevant for humans since the amount that’s in sunscreen that’s absorbed by the skin is miniscule.”
Some studies suggest that when exposed to UV radiation, retinyl palmitate generates free radicals — chemically reactive substances whose interactions with DNA may cause mutations leading to cancer. However, these studies have examined retinyl palmitate in isolation. In practice, when applied to the skin, antioxidants like vitamins C and E neutralize free radicals.
Applying sunscreen may seem like a simple task: squirt, rub and go. Yet, according to Dr. Lui’s research, most people only apply about one-third to half of the amount that they need, leaving lots of skin exposed to dangerous UV radiation.
You need about one ounce of sunscreen to cover your entire body. That’s the equivalent of one full shot glass. To ensure you’re covered, be systematic. Start from your forehead and work your way down over your torso, arms, hands and legs, all the way to the tips of your toes. Have a friend help you with hard to reach places, such as your back. For the best protection, reapply it after heavy sweating or swimming.
Dr. Lui emphasizes the importance of fostering skin cancer prevention habits in children from a very young age. “Parents should realize that early exposure to the sun has significant implications for the development of skin cancer at a later age,” he says. “Just like teeth brushing, the earlier you start teaching a child how to properly apply sunscreen the better.”
Since the advent of modern sunscreens, their efficacy has been measured by their Sun Protection Factor, or SPF, which measures protection against UVB radiation. SPF is not a measure of the amount of protection, per se, but indicates how long it will take for UVB to redden skin. For example, someone using SPF 20 will take 20 times longer to redden than without it. And rumour has it that SPF 30 is the most you need; any higher is a marketing ploy.
Not so, says Dr. Lui.
“In theory, SPF 30 is enough,” he says. “But in practice most people do not apply enough sunscreen to begin with. To increase your safe margin of error when applying sunscreen, choose a high SPF—60 is a good idea in his opinion. This is especially true for people with fair or sensitive skin.”
Despite recent record-breaking sunny weather, if you live on the coast you’re likely familiar with the month of “June-uary”: that time of year coastal British Columbians sport jackets while the rest of Canada is beginning to bathe in sunshine.
“Many people think that if it’s cold, sunscreen is pointless,” cautions Dr. Lui. “The truth is, there is a much lower risk for most people on cloudy and rainy days, but if you can see the sun there’s a risk. If it’s bright outside, apply sunscreen to any exposed skin.”
And if you doubt the doctor, just ask any racoon-eyed spring skier bombing down Blackcomb or Big White.
According to Dr. Lui, cowboys had it right: wide brimmed hats are best for sun protection. Short brims, not so much — meaning that Canucks cap you’ve been donning daily may look cool, but it’s not doing anything to protect you from the sun.
A good general rule for hats: the brim should be at least the width of the palm of your hand, and cover the full circumference of your head.
“The truth is that sunscreen should really be your last line of defence against skin cancer,” says Dr. Lui. “It’s like driving: just because you have seat belts and air bags doesn’t mean you should drive like crazy.”
In other words, limit your risk of skin cancer by first limiting your exposure to the sun. Minimize the time you spend outdoors on sunny days, especially between 11am and 3pm. If you do go out, wear long sleeves and long pants with a tight weave, protect your eyes with UV-blocking sunglasses and invest in a wide-brimmed hat. And, last but not least, use a good layer of CDA approved sunscreen that’s SPF 30 or higher as your
last line of defence between any exposed skin and harmful UV radiation.
Communications Officer, BC Cancer
Provincial Health Services Authority
PHSA media line: 778-867-7472