The thoracic oncology research landscape has evolved quickly in recent years; changing what is known about potential risk factors, prevention, and management of lung cancer. Understanding the underlying causes of lung cancer not only can help in preventing the disease, it may also alter the course of treatment, making identifying potential risk factors more important than ever.
While tobacco drives a large percentage of thoracic malignancies, it is not the only risk factor. At the 2024 World Conference on Lung Cancer, experts presented a series of lectures exploring these determinants during a plenary session titled, Unmasking Lung Cancer: Exploring the Rising Influence of Non-Tobacco Factors.
To begin, Leticia Nogueira, PhD, MPH, Scientific Director of Health Services Research at the American Cancer Society, discussed the impact of climate change and extreme weather events on lung cancer risk and management.
“We found that lung cancer patients whose treatment facility was impacted by a hurricane during their radiation treatment had worse overall survival than similar patients who were treated at the same facility previously,” said Dr. Nogueira.
Increasingly powerful natural disasters, such as hurricanes and wildfires, fueled by climate change damage medical infrastructure, break transportation links, disrupt supply chains, and interrupt access to medical care. Additionally, the changing frequency and severity of climate-related events make it challenging for communities to prepare and respond to these unpredictable circumstances, especially for those who rely on uninterrupted access to care, she said.
Dr. Nogueira also reviewed data that show how reliance on fossil fuels is a shared cause contributing to climate change and increased exposure to carcinogens, including airborne particulate matter (PM) 2.5 micrometers (μm) in diameter, which has been linked to increased risk of non-small cell lung cancer (NSCLC) with EGFR mutations.
“Air pollution from vehicle emissions, the same air pollution that is driving the greenhouse effect, also increases lung cancer risk,” she said. “Extracting, processing, transporting, and waste management of fossil fuels all release carcinogens into communities before and after they are consumed.”
Another talk by Pamela Ling, MD, MPH, shed light on the risks and harmful effects of vaping, with both tobacco and marijuana products.
“Many studies have shown that the liquids in e-cigarettes contain carcinogens—including volatile organic compounds and heavy metals—and e-cigarettes produce large amounts of particulate matter, including PM2.5,” Dr. Ling said. “In addition, there have been studies showing that exposure to e-cigarette aerosol can induce adenocarcinoma of the lung in mice.”
Dr. Ling, Professor of Medicine at the University of California, San Francisco, also pointed out an ongoing need for more research and regulation.
“We’re in a sort of tortoise and hare situation,” she said. “We have a very rapidly evolving product market, and we need research that addresses not just vaping nicotine, but vaping other substances, the co-use of multiple products, and the impact on health, including lung cancer,” she said.
Mariam Jamal-Hanjani, MD, PhD, Professor of Cancer Genomics and Metastasis, University College London, Research Department of Oncology, shared data on the role of air pollution in promoting lung cancer in non-smokers, particularly those with EGFR mutations. She presented findings that demonstrated a causal relationship between exposure to PM2.5 and the development of lung tumors in EGFR-mutant mice.
“We looked at three specific mouse models, two in which we induce the EGFR mutation and one in which we induce the KRAS mutation. Indeed, we see that compared to the control, in mice that are exposed to air pollution PM2.5, there is a development of lung adenocarcinoma tumors in all three models,” Dr. Jamal-Hanjani said.
Felipe Roitberg, MD, Coordinator for Research Innovation and Health Technology Assessment for the Brazilian University Hospitals network, discussed the impact of military conflicts on airborne carcinogen exposure, including recent examples from Iraq, Ukraine, and Gaza.
“Most of the buildings in Ukraine, especially in Kyiv, contain asbestos,” Dr. Roitberg said. “It’s highly linked to carcinogenesis, and it was found in more than 60% of the debris found in Ukraine, according to the environmental agency for the United Nations.”
And these exposures go beyond borders. For example, the impact of the Russia-Ukraine conflict can be felt in Europe, such as in Milan, Italy, where researchers have identified heavy metals and ambient PM2.5 linked to the conflict, he said.
Indoor air pollution has also been linked to an increased risk of lung cancer. Roselle B. De Guzman, MD, Associate Professor of Medicine at Manila Central University-FDT Medical Foundation Hospital, Philippines, highlighted how an increased incidence of lung cancer in patients with no smoking history may be attributable to household air quality.
Dr. De Guzman reviewed some common pollutants that can be found in homes, including cooking fumes and other harmful gasses and chemicals. She called for better screening protocols for people with no smoking history and increased awareness of indoor air pollution.
“Just like a leaking bucket will never hold water, no matter how much we pour in, we cannot give the best care—even with the best treatments—and the best, most accurate diagnostic test to our patients if we do not clear the air,” Dr. De Guzman said. “We could better serve our patients, and those people at risk, if we address the problem of indoor air pollution.”
