As per a recent comprehensive study, exposure to high concentrations of tiny airborne particles may increase the risk of developing lung cancer within three years.
The study published in the journal Nature, suggests that polluted air may be especially dangerous to healthy lung tissue that already has genetic changes that make it susceptible to becoming cancerous.
The research, which examined nearly 33,000 people with lung cancer, found that high levels of small pollutants were linked to an increased risk of developing EGFR-induced lung cancer, a type of cancer that typically affects non-smokers and people who do not smoke strongly.
“Cells with cancer-causing mutations naturally accumulate as we age, but they are normally dormant,” says cancer researcher Charles Swanton of the Francis Crick Institute in the UK.
“We have shown that air pollution awakens these cells in the lungs, encouraging them to grow and potentially form tumours.”
These results say the researchers, reiterate that air pollution is a leading cause of lung cancer and emphasize the need for action to reduce pollution and protect public health.
Air pollution and lung cancer
Air pollution, specifically fine particles smaller than 2.5 micrometres (PM2.5), has been linked to numerous health problems, including heart disease and lung cancer.
New evidence supports the idea that cancer begins in two steps: the acquisition of a driver gene (initiation) and a cancer risk factor that triggers the disease (promotion).
Mouse models have shown that PM2.5 exposure can cause changes in lung cells that could lead to cancer, and PM2.5 particles amplify the second step in the process.
An international team of researchers conducted a three-part analysis using environmental and epidemiological data sets to study the link between PM2.5 and lung cancer.
The analysis found that PM2.5 exposure was associated with an increased risk of developing EGFR-mutated lung cancer, with the risk increasing as PM2.5 exposure increased. The risk was higher in non-smokers or people who don’t smoke much.
“Taken together, these data, combined with published evidence, indicate that there is an association between the estimated incidence of EGFR-induced lung cancer and PM2.5 exposure levels and that 3 years of exposure to air pollution may be sufficient for this association to manifest itself,” the authors write.
Limitations and Future Directions
The researchers acknowledge that their study has limitations, such as the fact that cancer-prone mouse models develop tumors even without exposure to PM2.5. Furthermore, these models may not fully represent mutations found in healthy adult tissue.
Despite its limitations, the study provides researchers with a valuable opportunity to study early tumor growth in a controlled setting. In the future, scientists hope to find ways to reduce inflammation caused by air pollution, which could significantly lower the risk of lung cancer in non-smokers. This would require not only individual efforts but also collective actions to reduce overall exposure to air pollution.
Co-first author and cancer cell biologist William Hill of the Francis Crick Institute suggest that reducing inflammation caused by air pollution could have a significant impact on reducing lung cancer risk in non-smokers.
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