Most common female cancer in the world with more than 58,500 new cases in 2020, breast cancer may be made more common by chronic exposure to certain environmental pollutants. If this is not the first time that the hypothesis has been mentioned, researchers from the Léon-Bérard center in Lyon specializing in the fight against cancer have been able to establish a link between exposure to pollutants and the development of breast cancer.
“If the genetic, reproductive and hormonal factors of breast cancer are well identified, they do not explain all cases“, emphasizes the center’s “environmental cancer prevention” department. The researchers then wanted to see at what level air pollutants could have an impact on the occurrence of the disease. “Epidemiological and experimental studies have suggested that exposure to environmental pollutants, particularly those with endocrine disrupting effects, may have a role in the development of breast cancer.” can we read on the site of the Léon-Bérard center.
The Prevention department @CancerEnvironn from CLB presented the results of the large-scale XENAIR study. An increased risk of #Breast cancer during exposure to 5 pollutants in the population studied has been proven.
Learn more: https://t.co/Jawp9UMIN8pic.twitter.com/QRDG3hhk9i— Leon Berard Center (@CLCCLeonBerard) October 4, 2022
To achieve these results, more than 10,000 women, sick and not sick, were followed between 1990 and 2020, as part of the scientific program called Xenair. And of the eight pollutants studied (six are already classified as carcinogenic to humans by the International Agency for Research on Cancer), five are implicated in the increased risk of the disease.
Which particles increase the risk?
First in question, NO2 or nitrogen dioxide would increase the risk by 9%. It is mainly emitted by road traffic. Particles (PM10) and fine particles (PM2.5) from wood heating, road fuels and the construction and industrial sectors increase it by 8 and 13% respectively.
Benzopyrene (BaP), found in cigarette smoke or grilled meat (barbecue) increases the risk of tumors by about 15% But it is polychlorinated biphenyl (PCB153) from industrial combustion that presents the greatest increase risk, with 19%.
“We compared the exposures of sick women of the same age with those who were not sick over a given period by estimating the average annual exposures of their places of residence for the various atmospheric pollutants, which enabled us to estimate the risk they incur. for each of the selected pollutants”says Delphine Praud, researcher in epidemiology who participated in the study.
Up to 9% of breast cancers could have been prevented
Additional analyzes also showed a higher risk”in women exposed during their menopausal transition”, i.e. a period of higher sensitivity to two pollutants in particular, classified as endocrine disruptors: BaP and PCB153. However, no link has been made with exposure to cadmium, although it had been identified as an important cause of breast cancer through food.
Finally, improving air quality remains both the best lever for preventing breast cancer, but also for reducing the number of premature deaths. Every year, air pollution kills more than 7 million people worldwide according to WHO. “If exposure levels to NO2 or nitrogen dioxide were below the 2022 WHO recommendations, 1% of breast cancers in the Xenair population would have been prevented“, note the scientists. “En contrast, with exposure levels in line with WHO recommendations for 2021, nearly 9% of breast cancers would have been avoided.“
Source :
- XENAIR: links highlighted between breast cancer and exposure to atmospheric pollutants, Center Léon-Bérard, October 3, 2022