Data presented at the International Association for the Study of Lung Cancer (IASLC) 2024 World Conference on Lung Cancer add another piece to the puzzle of people diagnosed with lung cancer who never smoked.
Researchers at British Columbia Cancer Research Institute, Vancouver, Canada, presented data from 255 newly diagnosed patients with lung cancer and known EGFR mutation status who never smoked. They included geocoded information on their residential history from birth to date of diagnosis that included data on high-resolution concentration estimates of PM2.5 exposure. The team obtained annual exposure data going back to 1996.
Significant associations were observed between EGFR mutation and cancer stage among women (P=.197 in men, P<.001 in women). Patients diagnosed with stage IV lung cancer displayed higher proportions of EGFR mutations compared to those without.
Also of note, the team identified differences in the cumulative 3-year PM2.5 exposure before diagnosis in women who never smoked with EGFR mutations compared to those without. This trend persisted when examining cumulative 5-year exposure (33.7 vs 29.5 μg/m3, P=.024) before diagnosis, with higher exposure observed in the EGFR mutation–positive group. These associations did not occur in the men who never smoked, the team noted. Moreover, long-term exposure, such as 10-, 15-, and 20-year cumulative exposure to PM2.5, was not associated with EGFR mutation status in either men or women.
The International Agency for Research on Cancer categorized outdoor air pollution and its key component, PM2.5, as group 1 carcinogens in 2013, indicating that they cause lung cancer.
“The timing and duration of PM2.5 exposure that are most relevant for the development of lung cancer and lung cancer risk have not been well characterized,” said Yixian Chen, PhD, a researcher at British Columbia Cancer Research Institute, in a press release about the findings.1 “These findings suggest a potential impact of recent exposure to PM2.5 on lung cancer in people who never smoked, particularly among women, with significant differences in stage IV diagnoses among EGFR-positive patients.
The research team noted that further studies are needed to confirm if PM2.5 measurement over 3 to 5 years is adequate for lung cancer risk assessment.
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