People diagnosed with lung cancer have a higher likelihood of having microplastics in the lungs and a greater amount of these particles, according to a preliminary study that will be presented at the European Respiratory Society (ERS) Congress in Barcelona.
The investigation, conducted by an international team, analyzed 100 people undergoing bronchoscopy to investigate lung symptoms at the University Hospital of Larissa, in Greece. Half would subsequently be diagnosed with lung cancer, while the other 50 did not have the disease.
The researchers collected samples via bronchoalveolar lavage, using a saline solution to collect cells and other materials present in the airways. In half of the participants, a small sample of lung tissue was also collected.
Across the samples 232 microplastic particles were identified. In total, 70% of participants had detectable microplastics in at least one of the samples.
Compared with the two groups, the lung cancer patients had a higher likelihood of having detectable microplastics and a higher burden of these particles. In samples obtained through bronchoalveolar lavage, microplastics were detected in 66% of cancer patients, versus 46% of people without the disease.
The plastics most frequently identified were polypropylene and polyethylene, materials used in everyday products, including packaging, textiles, and various consumer goods.
The results also suggest that microplastics are not distributed evenly in the lungs. Participants who had larger quantities of particles in the bronchoalveolar lavage tended to have lower concentrations in the corresponding tissue samples, and vice versa. For the researchers, this difference may be related to the fact that the two techniques collect particles present in different areas of the lung.
Despite the association found, the authors emphasise that the study does not demonstrate that microplastics cause lung cancer. One possibility is that these particles contribute to inflammatory processes or other biological mechanisms associated with the disease. But it is also possible that the lungs affected by cancer retain microplastics differently from healthy lungs.
“The results suggest that inhaled microplastics can be found in human lungs more frequently than many people may imagine,” says Ilias Dimeas, a researcher at University College Dublin School of Medicine and at the University of Thessaly, and the author of the study.
The researcher adds that the study raises questions about how these particles interact with lung tissue. “What it shows is that microplastics were found more frequently and in greater amounts in cancer patients, which raises important questions for future research.”
The team is conducting new laboratory experiments to better understand the types of plastic identified and how they may interact with lung cells. The researchers are also analyzing samples from people with chronic lung diseases, seeking to understand whether microplastics may be related to scar formation in the lungs or to disease progression.
Barbara Hoffmann, president of the Advocacy Council of the European Respiratory Society and a researcher at the University of Düsseldorf, who did not participate in the study, believes that the research contributes to knowledge about human exposure to microplastics.
“Our understanding of the effects of microplastics on health is still at a very early stage, but we are beginning to realise that these small plastic particles are infiltrating various parts of the body,” she says.
Hoffmann stresses, however, that smoking remains “by far the main cause” of lung cancer and that air pollution is also recognised as a cause of the disease. According to the expert, more studies are needed to determine the possible role of microplastics in lung diseases, including cancer.
