LUGANO, Switzerland – Women living and working in places with higher levels of fine particle air pollution are more likely to get breast cancer than those living and working in less polluted areas. Results of the first study to take account of the effects of both residential and workplace exposure to air pollution on breast cancer risk are presented at the ESMO Congress 2023 in Madrid, Spain (1).

“Our data showed a statistically significant association between long term exposure to fine particle air pollution, at home and at work, and risk of breast cancer. This contrasts with previous research which looked only at fine particle exposure where women were living, and showed small or no effects on breast cancer risk,” said Professor Béatrice Fervers, Head of Prevention Cancer Environment Department, Léon Bérard Comprehensive Cancer Centre, France.

In the study, home and workplace exposure to pollution in 2419 women with breast cancer was compared to that in 2984 women without breast cancer over the period 1990-2011. The results showed that breast cancer risk increased by 28% when exposure to fine particle (PM2.5) air pollution increased by 10 µg/m3 – approximately equivalent to the difference inPM2.5 particle concentration typically seen in rural versus urban areas of Europe. Smaller increases in breast cancer risk were also recorded in women exposed to high levels of larger particle air pollution (PM10 and nitrogen dioxide). Fervers and colleagues now plan to investigate the effects of pollution exposure during commuting to get a complete picture of effects on breast cancer risk.

Professor Charles Swanton, the Francis Crick Institute, London, UK, whose research suggesting how PM2.5 particles may trigger lung cancer in non-smokers was presented at ESMO Congress 2022 (2), stressed the importance of the new findings with breast cancer.

“These very small particles can penetrate deep into the lung and get into the bloodstream from where they are absorbed into breast and other tissues. There is already evidence that air pollutants can change the architecture of the breast (3,4). It will be important to test if pollutants allow cells in breast tissue with pre-existing mutations to expand and drive tumour promotion possibly through inflammatory processes, similar to our observations in non-smokers with lung cancer,” he said. “It is very concerning that small pollutant particles in the air and indeed microplastic particles of similar size are getting into the environment when we don’t yet understand their potential to promote cancer. There is an urgent need to set up laboratory studies to investigate the effects of these small air pollutant particles on the latency, grade, aggression and progression of breast tumours,” he added.

“There is now strong epidemiological and biological evidence for the link between PM2.5 particle exposure and cancer, and there are good clinical and economic reasons for reducing pollution in order to prevent cancers,” said Professor Jean-Yves Blay, ESMO Director of Public Policy.

Following on a proposal from the European Commission in October 2022 to reduce the limit for PM2.5 particles in the air from the current 25 µg/m3 to 10 µg/m3 by 2030, ESMO urged a reduction in the PM2.5 limit still further to 5 µg/m3, in line with the World Health Organisation’s air quality guidance (5). “Reducing PM2.5 particles in the air to the WHO recommended level is critical because of their association with a variety of tumour types, including breast cancer,” Blay added. “We have a responsibility to push for this change, not only for people in Europe but worldwide where there are big variations in the pollution landscape.” The lower limit was indeed adopted by the European Parliament’s Environment, Public Health and Food Safety Committee in June 2023. 

More recently, in September 2023, the European Parliament adopted in plenary session its report on the ongoing revision of the EU Ambient Air Quality Directives, which reflects ESMO’s recommendations to set the annual limit value for Fine Particulate Matter (PM2.5) at 5 µg/m³. This adoption opens interinstitutional negotiations between the co-legislators – European Parliament, European Commission and EU Council – to agree on the final text of the directive. (6,7)

“By supporting our requests with solid scientific evidence, we are offering a new dimension to health public policy. The work is not over, and change will not happen overnight, but we are moving in the right direction,” the ESMO Public Policy Director concluded. 

Notes to Editors

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  1. Fervers B et al. Longterm residential and workplace exposure to air pollution and breast cancer risk: A case-control study nested in the French E3N cohort from 1990 to 2011 will be presented by Fervers B. during the Mini Oral Session on Monday, 23 October 2023, 16:30-18:00 CEST, at ESMO Congress 2023, Madrid (Bilbao Auditorium).
  2. Swanton C et al. Mechanism of action and an actionable inflammatory axis for air pollution induced non-small cell lung cancer: Towards molecular cancer prevention. Presented at ESMO Congress 2022, Paris, France Presidential Symposium 1, LBA1
  3. Niehoff NM et al. Outdoor air pollution and terminal duct lobular involution of the normal breast. Breast Cancer Res 2020; 22,100.
  4. Kotake R et al. An association between mammographic breast density and fine particulate matter among postmenopausal women. Environ Sci Pollut Res Int. 2023 Feb;30(10):25953-25958. 
  5. WHO global air quality guidelines: particulate matter (‎PM2.5 and PM10)‎, ozone, nitrogen dioxide, sulfur dioxide and carbon monoxide
  6. European Parliament. Revision of the ambient air quality directives
  7. European Parliament. Towards cleaner air for Europe

238MO Longterm Residential and Workplace Exposure to Air Pollution and Breast Cancer Risk: A Case-Control Study Nested in the French e3n Cohort From 1990 to 2011

B. Fervers1, M. Duboeuf1, A. Amadou1, T. Coudon1, L. Grassot1, E. Faure2, G. Severi3, F. Mancini3, P. Salizzoni4, J. Gulliver5, D. Praud1 [Text Wrapping Break]1Cancer And Environment Department, Centre Léon Bérard, Lyon/FRANCE, 2Exposome, Hérédité, Cancer Et Santé, Gustave Roussy, Villejuif/FRANCE, 3Exposome, Hérédité, Cancer Et Santé Inserm 1018, Gustave Roussy, Villejuif/FRANCE, 4Mécanique Des Fluides, Ecole Centrale, Ecully/FRANCE, 5Centre For Environmental Health And Sustainability, University of Leicester, Leicester/UNITED KINGDOM

Background: Air pollution, classified as carcinogenic to humans, is a major public health concern. Studies on breast cancer are scarce and remain inconsistent. We studied the association between breast cancer risk and long-term exposure to particulate matters (PM2.5, PM10) and nitrogen dioxide (NO2) estimated at the womens’ residential and workplace addresses. Methods: We conducted a case-control study of 2419 cases and 2984 individually matched controls nested in the French prospective E3N cohort, over the period 1990-2011. Controls were matched to cases on department of residence, age (±1 year); date (±3 months), and menopausal status at blood collection. Annual mean PM2.5, PM10 and NO2 concentration levels were estimated using a Land Use Regression (LUR) model (resolution 50m x 50m) and were assigned to women based on their geocoded residential and workplace addresses. The mean exposure was calculated for each woman from their inclusion into the E3N cohort to their index date (date of diagnosis of cases). Odds ratios (OR) and 95% confidence intervals (CI) were estimated using multivariate logistic regression models, for a 10 µg/m3 increase in PM2.5, PM10 and NO2. Adjustment variables were selected from the literature, using a directed acyclic graph. Results: The results showed a statistically significant linear increase in breast cancer risk related to mean exposure to PM2.5 (adjusted OR 1.28; CI 1.00–1.63, for an increment of 10 µg/m3). A numerically increased risk was observed for PM10 (adjusted OR1.09; CI 0.92–1.30) and NO2 (adjusted OR 1.05; CI 0.97–1.13) for an increment of 10 µg/m3. No effect modification by menopausal status was observed (p interaction 0.99, 0.90, and 0.86 respectively for PM2.5PM10 and NO2). Analyses by hormone receptor status showed a positive but not significant association for PM2.5 for oestrogen receptor positive (ER+) breast cancer cases (adjusted OR 1.32; CI 0.97–1.79). Conclusions: To our knowledge, this study is the first to investigate breast cancer risk associated with long term air pollution exposure at both, the subjects’ residence and workplace, estimated using a very fine spatial resolution LUR model. Future studies should consider exposure during commuting.

Legal entity responsible for the study: INSERM

Funding: Foundation or academic group WITHOUT funding from a pharma, biotech, or other commercial company[Text Wrapping Break]- ARC Foundation for Cancer Research (CANCAIR201601245), ANSES, French League against Cancer, Fondation de France

Disclosure: All authors have declared no conflicts of interest.