With the summer season in full swing, Canadians are enjoying the sun wherever they can find it, but skin cancer experts are warning that some of the prevailing myths around sun exposure and sun protection can be dangerous.

An older myth that still persists is the misguided idea that having a "base tan" reduces the need for sunscreen.

"Base tan is not a term dermatologists use," said Dr. Cheryl Rosen of the dermatology clinic at the Toronto Western Hospital. "What it really means is getting sun damage to allow yourself to get more sun damage later."

A base tan exposes cells to ultraviolet radiation without any protection, which leads to DNA damage that the body might not be able to repair completely, Rosen said. It ultimately leads to skin cancer, pre-skin cancer or wrinkling.

Rosen said she is concerned that the incidence of skin cancers continues to rise in Canada and people aren't protecting themselves as much as they should be.

One myth that prevents people from slathering on the two to three tablespoons of sunscreen dermatologists recommend is the idea that sunscreen needs to be applied 20 minutes before going outside.  

"I would like to get rid of that because I'm afraid people will say, 'Oh, no, it's five minutes before I go out so there's no point in putting it on," Rosen said. "Really, sunscreen begins to work as soon as you put it on. Maybe there is a bit better absorption if you put it on a bit ahead of time."

hi-sunscreen-ap-852

Sunscreen begins to work as soon as you apply it. (Rich Pedroncelli/Associated Press)

Experts also suggest that people:

  • Stay in the shade between 10 a.m. and 4 p.m.
  • Cover up as much as possible, including wearing sunglasses.
  • Look for sunscreens that provide a broad spectrum of protection from both UVA and UVB radiation.
  • If you're in the water, make sure your sunscreen is water-resistant.

"I think in the summer people should put their sunscreen on in the morning like they brush their teeth. It should be part of your routine," Rosen said.

People tend to forget to apply sunscreen to the back of the neck and top of the ears.

But while those are all good tips, sunscreen will not provide complete protection.  

"Health Canada says you can't call it a sunblock anymore, and that's because none of the sunscreens are perfect," Rosen said. "Some UV gets through."

The Canadian Cancer Society recommends that people use a sunscreen with SPF 30 if they work outdoors or plan to be outside for most of the day.

Rosen considers SPF 30 to be the minimum protective value against sunburn. A higher level means more protection, but it doesn't last longer. 

People with an abnormally high sensitivity to sunlight have greater benefits with a SPF higher than 50, Rosen said. These sunscreen products will soon be labelled SPF50+, the society noted.

No one knows whether a higher SPF offers greater value for DNA damage. 

Dermatologists say sunscreen creams and lotions tend to provide better coverage than sprays or liquids.

While UV protective clothing helps, it isn't essential, Rosen said. Clothing made of a tightly woven fabric also offers protection.

Ian Anderson, 58, of Brampton, Ont., didn't pay attention to sun protection until it was almost too late. A mole on his back grew from the size of a dime to about the size of a toonie in the course of a month and changed colour.

"They did a biopsy of the mole and found that it was full of cancer, and that's the first I heard of it," he said.

He was diagnosed with Stage 4 melanoma.

"I still love the sun, I'm not going to deny that," Anderson said. "I put a hat on and put on the sunscreen. A lot of times, I'll wear a three-quarter length sleeve. You try to cover up the best you can, but you can't run from it. You want to enjoy it, too."

With files from CBC's Christine Birak and Marcy Cuttler