Beyond the haze: What wildfire smoke means for lung health

In recent years, increased wildfire activity and smoke exposure has become so common that checking the air quality index is as routine as checking the weather forecast. There’s good reason for that. Clinicians and researchers specializing in lung cancer are seeing more cases among younger adults and people who have never smoked, making environmental exposures an increasingly important area of study. 

“In Canada, we are seeing 40 per cent of people who are diagnosed with lung cancer whose tumours are not attributable to tobacco,” says Dr. Aaron Goodarzi, PhD, associate director of basic and translational research at the Arnie Charbonneau Cancer Institute.

Currently, awareness of these risks is low despite the fact that the Canadian Cancer Society reports long-term exposure to many environmental toxicants such as radon, asbestos, arsenic and air pollution has also been shown to increase the risk of developing lung cancer.

“In my lung cancer clinics, I'm seeing patients that are young, as young as in their 20s and 30s, who have a diagnosis of lung cancer and have never smoked. In those cases, there is certainly concern for non-tobacco causes of lung cancer, in particular air pollutants such as radon and wildfire smoke,” says Dr. Doreen Ezeife, MD, a medical oncologist who treats lung and breast cancer at the Arthur J.E. Child Comprehensive Cancer Centre and a clinical associate professor at the Cumming School of Medicine (CSM).

In response, a team of researchers led by Goodarzi, also a professor in the CSM, will be measuring levels of non-tobacco-related cancer risks inside homes across the country to better understand the dangers of combined exposures and identify those who may benefit from earlier screening. 

Goodarzi says the research comes at a time when radioactive radon levels in indoor air are at historic highs while Canadians are experiencing more frequent and prolonged exposure to wildfire smoke.

“It has never been more important to study these mixtures and understand what they mean for our health,” Goodarzi says.

Co-investigator Ezeife says that both dose and duration matter when outdoor conditions are smoky. 

“There are several carcinogens present in wildfire smoke that can contribute to lung cancer,” says Ezeife. “We don’t really want to have repeated exposures over long periods of time.”

The team will also examine how family genetics and the body’s ability to repair DNA damage may influence an individual’s risk of developing lung cancer from these environmental pollutants. Through this research, supported by the Canadian Institutes of Health Research and the Canadian Cancer Society, the scientists hope to strengthen public awareness and promote reliable health information to help guide policy changes to reduce future exposures to environmental-related causes of lung cancer.

“We need to understand how these non-tobacco exposures contribute to a person’s risk. The findings will help improve lung cancer screening guidelines and support earlier diagnosis,” says Goodarzi.