5 to 10% of cancers are linked to environmental factors. How can we evaluate and prevent the influence of these risk factors linked to pollution and our lifestyles?
At the beginning of the 20th century, doctors noticed a high number of bladder cancers among workers working in the production of certain chemical dyes. Others, at the same time, made a link between the pioneers of radiology and a normal incidence of skin cancer. It is from these observations that the first links are established between the appearance of cancer and the immediate environment, a question that has today become a major issue for cancer research, with numerous risk factors identified in this called the environment.
Whether in terms of treatments, screening and prevention, research on cancers has progressed enormously in recent years. But despite this progress, cancers remain the leading cause of death in the world.
If many risk factors have been highlighted (smoking, alcohol consumption or unbalanced diet), the role of environmental factors has become an important concern for cancerology.
Since cancers are of multifactorial origin, how can we make the link between certain environmental exposures and the appearance of cancer? How to assess the role of environmental factors?
With :
- Robert Baroukidoctor, biochemist and toxicologist, head of the metabolic biochemistry department at Necker-Enfants Malades Hospital
- Delphine Praudenvironmental epidemiologist and at the Léon Bérard Lyon Center and at the NSERM, Environment Cancer Prevention Department
- Mathilde Touvier, director of research in nutritional epidemiology at Inserm, professor at the Collège de France in Public Health on the 2022-2023 annual chair
=> To participate in the Nutrinet health study
Carcinogenic environmental factors
These carcinogenic environmental factors, whether chemical, physical, biological, but also psychosocial, are called “expozom”. Without forgetting all individual behaviors, whether diet, smoking, alcohol consumption, or physical activity, factors on which it is possible to act affirm the three specialists, whether at the individual level and collective to modify the risk of cancer for the current and future generations. For atmospheric pollution, this concerns all the pollutants that we breathe, fine particles particularly in the urban environment. They recall that “For example, 80% of breast cancers are hormone-dependent cancers linked to exposure to endocrine disruptors.“.
There are several classifications today, including that of the WHO International Center for Research on Cancer, which regularly produces monographs or collective assessments, which brings together toxicologists, epidemiologists and researchers from different disciplines in order to to review all available scientific literature. It is all of this literature that is examined closely and for which levels of evidence are then established, a gradation that helps guide public policies on the factors for which there is a significant level of certainty. It is the consistency of this scientific evidence that makes it possible to classify to confirm when a source of nuisance is carcinogenic for humans.
How to reduce the risk of cancer?
A study obtained by the National Cancer Institute was able to estimate that of the approximately 142,000 new cases each year, 40% of these cases could be avoided by changing behavior, firstly tobacco, then alcohol, etc. unbalanced diet, overweight, lack of physical activity… For Mathilde Touvier, “it’s important both at the individual level, to change, to modify our behavior for what can be, and then to also act at the political level to modify the environment in which we operate*”.
To act on air pollution, Delphine Praud draws attention to “the importance of putting in place policies and regulations that could reduce concentrations, but also raise awareness of our behavior“.
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