If you've never touched a cigarette or vaped, lung cancer may be the furthest thing from your mind.

While the number of cases of tobacco-related lung cancer has fallen, more non-smokers are surprisingly getting the disease, according to a doctor.

"We often say if you have lungs, you can get lung cancer," Dr. Natasha Leighl, clinician investigator with Princess Margaret Cancer Centre in Toronto, said in an interview with CTV's Your Morning on Monday.

With the rise in cases among non-smokers, Leighl shared ways to prevent it.

What are the biggest risk factors?

You're more likely to get lung cancer if you're exposed to second-hand smoke, air pollution, as well as radon, Leighl said. Radon is a radioactive gas created from the natural decay of uranium in all rocks and soils, according to the World Health Organization.

Genetics also plays an important role in developing lung cancer, she added.

There are differences in lung cancer between non-smokers and smokers.

"Ninety per cent of patients with lung cancer in non-smokers have a specific gene that's gone wrong in cancer," she said.

The good news is new treatments and therapies can help people who've been diagnosed with cancer live years longer than in the past, she said.

Cancer statistics

It's a mystery why more women are getting lung cancer, Leighl said. Approximately 17,300 women developed lung cancer this year compared to 14,800 men, according to the Canadian Cancer Society.

Among non-smokers, lung cancer is more common in women of Asian ancestry, she said.

"We don't understand it 100 per cent," Leighl said.

She cited factors such as genetics, air pollution, poor ventilation in homes, using wood stoves, as well as exposure to diesel and cooking fumes.

"These all increase risks and often increase risks specifically in women," she said.

How to protect yourself

Regardless of your gender, one of the best ways to protect yourself is to avoid smoking, vaping and being exposed to smoke in general, Leighl said.

"Make sure that you really protect yourself and your lungs," she said. "If it's not in the air, it's not supposed to be in your lungs."

If you have unusual symptoms, such as coughing and pneumonia that persist, see your doctor, she advises.

"It may take several visits because even our family doctors or our nurse practitioners aren't as aware of the risk of lung cancers in non-smokers ... The earlier we find it, the better you'll do."