Doctors are seeing a growing number of non-smokers, especially women, with lung cancer

Although smoking remains the leading risk factor, the Canadian Cancer Society estimates about a quarter of lung cancer cases in the country are non-smokers.

In addition, more of those non-smokers are women than men and it’s not clear why, according to Jessica Moffatt, vice-president of programs and advocacy at the Lung Health Foundation.

“One of the theories is that potentially estrogen is doing something to perpetuate tumour growth, but it’s all theories at this point,” she said.

What scientists do know is that environmental factors contribute to lung cancer risk, especially radon gas.

According to Health Canada, long-term exposure to radon — an invisible, radioactive gas from the breakdown of uranium in soil and rocks — is the number one cause of lung cancer among non-smokers. The agency says radon is present to some degree in every home and urges everyone to get a radon test kit to check their levels.

Other risk factors include exposure to second-hand smoke, asbestos and the fine particulate matter in air pollution, Moffatt said.

As wildfires rage across the country, the effects of that smoke is “a huge concern for us” and is an area being studied to determine lung cancer risk, she said.

Dr. Rosalyn Juergens, a medical oncologist at McMaster University and Hamilton Health Sciences Centre, said studies have shown that people living in areas with high air pollution rates have a higher risk of developing lung cancer.

Over about 20 years in practice, she has “absolutely” seen a rise in non-smoking lung cancer patients.

“It was uncommon for me, not never, but uncommon for me, to see a never-smoker when I first started in practice. And we are definitely seeing more and more,” said Juergens, who is also the president of Lung Cancer Canada.

It’s not clear whether there are more non-smokers getting lung cancer or if they just make up a greater proportion of the patients as fewer people smoke than ever before, she said.

Many of her non-smoking patients are women, but people simply aren’t aware of lung cancer as a women’s health issue, she said. When non-smokers reach her office, their cancer is often in advanced stages.

“More women will die of lung cancer than will die of breast cancer, ovarian cancer, and cervical cancer combined,” Juergens said. “One in five of them will be people who have never touched a cigarette a day in their lives.”

Although organized lung cancer screening programs have been running in British Columbia, Ontario and Nova Scotia since 2022, they only target smokers, so non-smokers don’t get the benefit of that early detection.

In addition, lung cancer is often not top-of-mind for primary-care providers when non-smoking patients come in with a cough, Juergens said.

“The tricky part about lung cancer is symptoms are generally very subtle, right? Your lungs inside don’t have nerve endings. So it’s not like you’re going to get a pain. You’re never going to feel a lump,” she said.

But the good news for many patients, Juergens said, is that lung cancer treatment has advanced dramatically since the 1990s, when chemotherapy was often the only option.

“We do things called next generation sequencing on the vast majority of lung cancers, and that helps us to sort what exact type of lung cancer it is and pick the right treatments,” she said.

Advocates call for equal access to targeted cancer medication across the country. Additionally, people should seek medical attention if they have a cough that lasts more than two or three weeks.

“Anyone with lungs can get lung cancer.”

The Canadian Press

~WakenyaCanada