Long-Term Exposure to Air Pollution and Risk of Lung Cancer

Long-term cumulative exposure to air pollution should be included in assessments of lung cancer risk, according to researchers. 

The researchers evaluated the impact of cumulative exposure to particulate matter measuring 2.5 micrometers or smaller (PM_2.5) on lung cancer risk in women with no history of smoking. 

The results suggested that evaluating a patient’s 3-year cumulative PM_2.5 exposure may underestimate the impact of such exposure on lung cancer risk, when compared with 20-year PM_2.5 exposure. 

These findings were presented at the IASLC 2022 World Conference on Lung Cancer by Renelle Myers, MD, of BC Cancer in Vancouver, Canada. 

The study included 236 women in Vancouver who were newly diagnosed with lung cancer and had no history of smoking. The researchers collected information on patient demographics, entire residential history, and lung cancer risk factors. 

Most of the patients studied were born outside of Canada (79.7%), and a majority were Asian (71.2%). The mean age at lung cancer diagnosis was 66.1 years. The most common diagnosis was adenocarcinoma (92.8%), 56% of patients had stage III/IV lung cancer, and 46.7% had EGFR mutations.

To quantify cumulative PM_2.5 exposure, the researchers used a high-spatial resolution global exposure model based on satellite-derived data.

Of the 48 patients born in Canada, only 1 had cumulative PM_2.5 exposure greater than 10 ug/m³ at both 3 years and 20 years.

Among the 188 patients born outside of Canada, 2.1% (n=4) had a 3-year cumulative PM_2.5 exposure greater than 10 ug/m³, and 20.2% (n=38) had a 20-year cumulative PM_2.5 exposure greater than 10 ug/m³ (P ≤.0001). 

Dr Myers pointed out that only 1 patient born outside of Canada fell within the recommended safe dose of air pollution exposure, which is PM_2.5 exposure below 5 ug/m³.

In the overall cohort, higher PM_2.5 exposure was observed for patients with EGFR mutations in the 3-year exposure data (P =.049) but not in the 20-year data (P =.188). 

When the researchers divided patients by birthplace, there were no significant differences according to EGFR status in the 3-year data or the 20-year data for patients born in Canada or for patients born in other countries. 

“Our study points to the importance of incorporating this long-term cumulative exposure to ambient air pollutants in the assessment of individual lung cancer risk, of course, in combination with traditional risk factors,” Dr Myers said in closing.

She added that 3-year assessment may underestimate the adverse health effects of chronic exposure to PM_2.5.

“And depending on the country of residence, I think that even a 20-year cumulative exposure may underestimate the effects of PM_2.5, as we’re not capturing childhood and adolescent exposure when the lung is developing and what effect that will have,” Dr Myers concluded. 

Reference

Myers RL, Tammemagi MC, Brauer M, et al. Evaluation of outdoor air pollution exposure (PM2.5) in female non-smoking lung cancer patients. Presented at WCLC 2022. August 6-9, 2022. Abstract 2268.

This article originally appeared on Cancer Therapy Advisor