Women who live and work in places with higher levels of particulate matter in the air are more likely to develop breast cancer than women who live and work in less polluted areas.
The results of the first study to consider the impact of domestic and occupational air pollution on breast cancer risk will be presented at the ESMO European Society of Medical Oncology Congress 2023 in Madrid.
“Our data showed a statistically significant association between long-term exposure to particulate air pollution at home and at work and breast cancer risk. This is in contrast to previous research that only considered fine dust pollution where women lived and showed little or no effect on breast cancer risk,” said Professor Béatrice Fervers, Head of the Department of Cancer and Cancer Prevention Environment at the Léon Bérard Comprehensive Cancer Center ( France).
The study compared pollution at home and at work of 2,419 women with breast cancer with that of 2,984 women without breast cancer between 1990 and 2011. This is what the results showed the risk of breast cancer increased by 28% when levels of fine particulate matter in the air (PM2.5) increased by 10 µg/m3 – roughly equivalent to the difference in PM2.5 concentrations typically seen in rural and urban areas in Europe. A smaller increase in breast cancer risk was also found in women exposed to high levels of air pollution from larger particles (PM10 and nitrogen dioxide). Fervers and her colleagues now plan to study the effects of pollution exposure while commuting to get a complete picture of the impact on breast cancer risk.
Professor Charles Swanton from the Francis Crick Institute in London, UK, whose research suggesting that PM2.5 particles may cause lung cancer in non-smokers was presented at the 2022 ESMO Congress, underlined the importance of new findings in breast cancer.
“These very small particles can penetrate deep into the lungs and enter the bloodstream, where they are absorbed by the breast and other tissues.” There is already evidence that air pollutants can change the architecture of the breast. “It will be important to test whether contaminants allow breast tissue cells with pre-existing mutations to expand and drive tumor promotion, perhaps through inflammatory processes, similar to our observations in non-smokers with lung cancer,” he said. “It is very worrying that small air pollutant particles and plastic microparticles of similar size are being released into the environment, although we do not yet know their potential to promote cancer.” “It is urgent to start laboratory studies to assess the impact of these small air pollutant particles to study the latency, grade, aggressiveness and progression of breast tumors,” he added.
“There is now Strong epidemiological and biological evidence linking PM2.5 exposure to cancerand there are good clinical and economic reasons to reduce pollution to prevent cancer,” said Professor Jean-Yves Blay, Director of Public Policy at ESMO.
Following a proposal from the European Commission in October 2022 to reduce the limit value for PM2.5 particles in the air from the current 25 µg/m3 to 10 µg/m3 by 2030, ESMO is pushing to further reduce the PM2.5 limit to 5 µg/m3, in line with World Health Organization air quality guidelines. “Reducing PM2.5 particles in the air to WHO-recommended levels is critical due to their association with various types of tumors, including breast cancer,” Blay added. “We have a responsibility to drive this change, not just for residents of Europe, but across the world, where there are wide disparities in pollution.” In fact, the lower limit was approved in June 2023 by the Committee on the Environment, Public Health and Food Safety of the approved by the European Parliament.
Most recently, in September 2023, the European Parliament adopted in plenary session its report on the ongoing review of the EU directives on air quality, which reflects the ESMO recommendations to set the annual limit value for particulate matter (PM2.5) at 5 µg/m³. This adoption opens interinstitutional negotiations between the co-legislators – the European Parliament, the European Commission and the Council of the EU – to agree on the final text of the directive.
“By backing up our demands with solid science, we offer a new dimension to public health policy.” The work is not yet finished and change will not happen overnight, but we are moving in the right direction,” concluded the ESMO- Director of Public Policy.
REFERENCES
Long-term exposure to nitrogen dioxide air pollution and breast cancer risk: A nested case-control in the French E3N cohort study
An association between mammographic breast density and particulate matter in postmenopausal women