Particulate matter PM 2.5 and PM10 that are found in our toxic urban air in most cities and are usually associated with premature heart attacks and deaths, are now suspected of increasing the risk of breast cancer as well.
A 20-year study from six states in the US and France has shown a correlation between indoor and outdoor exposure to particulate matter and breast cancer.
There are multiple studies linking PM2.5 — particles formed in the atmosphere through chemical reactions of gases such as sulfur dioxide, nitrogen oxides, and certain organic compounds — with premature deaths, particularly in people who have chronic heart or lung diseases, and reduced lung function growth in children.
It was only in 2015 that the International Agency for Research on Cancer concluded that PM in outdoor air pollution causes lung cancer.
The PM2.5-breast cancer link is too new, with barely a handful of studies from the West suggesting a correlation. Medical oncologists say air pollutants trigger an inflammatory response in the body that could be the reason for the increased cancer risk.
The French study, which was presented at the European Society for Medical Oncology (ESMO) Congress 2023 in Madrid, found that breast cancer risk increased by 28% when exposure to fine particle (PM2.5) air pollution increased by 10 µg/m3. It studied 2,419 women with breast cancer and another 2,984 women without breast cancer between 1990 and 2011.
The US study, published in the Journal of the National Cancer Institute in early September, found an 8% increase in breast cancer incidence among those living in areas with higher PM2.5 exposure. The study followed five lakh women and men over a 20-year period and found 15,870 breast cancer cases
Experts said PM2.5 could penetrate deep into the lung and get into the bloodstream from where they are absorbed into breast and other tissues. Stating there is evidence that air pollutants can change the architecture of the breast, they said tests should be done to see if these microscopic pollutants “allow cells in breast tissue with pre-existing mutations” to expand and cause tumours.
Back in India, the incidence of breast cancer has increased by 50% between 1965 and 1985. As per the Globocan data 2020, in India, breast cancer accounted for 13.5% (1,78,361) of all cancer cases and 10.6% (90,408) of all deaths. Studies estimate the global burden of breast cancer is expected to cross almost 20 lakh by 2030.