Emerging environmental threats in cancer
By: Dr. James Aw, Chief Medical Officer, OMERS
April 27, 2026
Cancer is common and starting to show up at younger ages. Over 40% of us will be diagnosed with cancer during our lifetime and 13 cancers including colorectal, cervical, pancreatic, kidney and multiple myeloma are on the rise in younger adults.
40% of cancers are linked to modifiable risk factors like tobacco smoking, infections (i.e. HPV, hepatitis, EBV, Helicobacter pylori), excess alcohol, obesity, ultraviolet radiation, physical inactivity, poor diet, air pollution and work-related chemical exposures. Believe it or not, this is good news because we can prevent several cancers through lifestyle choices!
The proposed mechanisms leading to cancer include oxidative stress, chronic inflammation, DNA damage and cell signaling pathway disruptions that are triggered by genetics, social and environmental exposures. Accelerated aging of cells and cancer growth can be influenced by a process called DNA methylation (epigenetics). More on this later.
Life on planet Earth means co-existing with human-made chemicals and potential health hazards. Emerging threats include “forever chemicals” (PFAs aka per and polyfluoroalkyl substances), microplastics, vaping, wildfire smoke and hormone disrupting chemicals (EDCs like bisphenols, phthalates, flame retardants, pesticides). Humans are exposed to these chemicals through drinking water, consuming contaminated food and breathing polluted air.
Cancer prevention research is complicated. Most emerging evidence on chemical causes of cancer relies on animal studies, observational human data and biological vulnerability/plausibility. There is also a difference between causation and association. Other aspects to consider are the underlying health of the individual (immune system, genetics), chemical exposure burden (dose, length of time, cumulative effects) and latency or lag period (e.g., asbestos can cause lung cancer 20 years after the original exposure). Research on Cancer from the World Health Organization is an authority on reviewing the evidence on whether a chemical could be linked to cancer. Most frequently studied populations include contaminated communities, exposed workers and general population cohorts. However – it is not perfect since IARC does not look at all the clinical factors that may contribute (or protect one) from developing cancer.
Let us look at the environmental risks that are emerging that may be linked to cancer (i.e., carcinogenic).
“Forever chemicals” (PFAS/PFOA aka per and polyfluoroalkyl substances/perfluorooctanoic acid)
These are man-made consumer products (i.e., non-stick cookware, water resistant clothing, food packaging, cosmetics, etc.) made from strong chemical bonds of carbon and fluorine atoms that do not easily break down in the environment. PFAS are linked to kidney and testicular cancers and potentially to breast, thyroid, lung, liver and prostate cancers. Long term exposure leads to health risks, and most individuals have some detectable levels circulating in the blood. Most studies on associations with cancer are on exposed workers, contaminated communities and general population cohorts.
Micro and Nanoplastics (MNPs)
Contaminant levels have been found in human tissues and tumours. Animal studies have shown a link to cancer, but nothing definitive in humans.
E-cigarettes and Vaping
Mice studies have shown lung cancer after 54 weeks of e-cigarette exposure. E-cigarettes contain chemicals like formaldehyde, nitrosamines, benzene and heavy metals. Emerging studies have shown that nicotine based e-cigarettes may be linked to oral and lung cancer, with the greatest risk for earlier onset lung cancer in those that smoked (tobacco) and vaped. However – the latency/lag time to developing cancer in humans may be 20 years and e-cigarettes have a much lower cancer potency than tobacco (which is a well-established carcinogen). The main concern is with adolescents and young adults who are high consumers of e-cigarettes.
Wildfire smoke and climate change
Climate change can increase wildfire frequency, UV radiation, water contamination and disrupt food chains. Wildfire smoke has carcinogenic chemicals (PM2.5 fine particulate matter, PAHs, benzene, formaldehyde) and has been associated withincreased risk of lung cancer and brain tumours. Cancer survivors are also particularly vulnerable to wildfire smoke, and it may worsen health outcomes and increase mortality.
Endocrine (hormone)-disrupting chemicals (EDCs)
Fossil fuel-generated chemicals like bisphenols (BPA/BPS), phthalates, flame retardants (PBDEs) and pesticides are also potentially linked to hormone sensitive cancers like breast, ovarian, endometrial, testicular, prostate, thyroid and childhood cancers (leukemia).
Is there any good news?
Yes! As mentioned before, 40% of cancers are preventable through healthy lifestyle choices (avoid tobacco, excessive alcohol, physical inactivity, UV radiation, poor diet, obesity) and cancer screening with your physician. Increasing knowledge of the mechanisms of cancer like DNA methylation, chronic inflammation and immune system effects are leading to earlier diagnostic tests (multicancer early detection, blood based liquid biopsy, microbial fingerprints – microbiome/genome), targeted therapies (cell based) and cancer vaccine development (personalized mRNA vaccines). AI powered tools will help with predictive analytics and advanced diagnostics to assess cancer risks from the individual and the environment. Societal efforts must continue to combat the negative health effects of climate change, pollution, social injustices, unsafe workplaces and preventable infectious diseases.
Remember that cancer research is difficult. Humans are not mice. Chemicals that are found to be associated with cancer do not mean they cause cancer.
Finally, remember that it is important to live and not be in constant fear of your environment. Be informed and control what you can control. Avoid unnecessary exposures to known carcinogens and focus on maintaining a healthy lifestyle. As someone wise once said, “All things in moderation, including moderation!”
For those who want to learn more!