More Evidence Ties Microplastics to Lung Cancer

Inhaled microplastics were frequently found lodged in people’s lungs, especially people with lung malignancy, researchers found.

In a prospective observational study of 100 people undergoing diagnostic bronchoscopy, those with lung cancer more frequently had microplastic particles detected on bronchoalveolar lavage (BAL) and airway tissue sampling (66% vs 46% in those without lung malignancy, P=0.044).

There was a median one microplastic particle found from BAL in these cancer patients, as opposed to approximately zero in controls (P=0.045), and the association between microplastic burden and lung malignancy remained significant after adjustment for smoking exposure, age, and sex (OR 2.00, 95% CI 1.01-3.95), according to Ilias Dimeas, MD, of University College Dublin, and the University of Thessaly, Greece.

Dimeas presented his group’s study during a poster session at the European Respiratory Society (ERS) Congress in Barcelona, Spain.

“This type of study doesn’t tell us why we found more microplastics in the samples from lung cancer patients,” he cautioned in a press release. “Microplastics could contribute to inflammation or other biological processes that may contribute to diseases like cancer, but it is also possible that diseased lungs simply retain particles differently than healthy lungs.”

“What it does show is that microplastics were found more often and in greater numbers in patients with lung cancer, which raises important questions for future research. We have already begun more laboratory experiments to better understand the types of plastics involved and how they may interact with lung cells,” Dimeas reported.

Microplastics are indirect products of mass industrial processes and are increasingly found in the air, water, soil, and food all around the planet. Much controversy surrounds these particles due to their ubiquitous infiltration into human tissue and observed links to human diseases such as cognitive disability and cardiovascular disease.

Experts currently advise certain measures to avoid microplastic exposure, such as not burning plastics, not using nonstick and plastic cookware, not reheating or washing plastic containers in a dishwasher, replacing plastic wrap with aluminum foil, buying food and drinks in glass jars instead of plastic, removing all synthetic fabrics in the home, and avoiding tobacco smoke.

The true effects of microplastics on human health remain poorly understood, however.

“This study is an important preliminary study, but it does not establish that microplastics are a cause or risk factor for lung cancer,” commented Ria Devereux, PhD, of the University of East London.

Indeed, like most studies in this area, the present work was limited by its observational design and small sample.

“I would still be interested to know occupational exposures, exposure to air pollution, other underlying lung diseases, the specific type and stage of lung cancer, and whether participants had undergone previous medical procedures or interventions that could affect microplastic exposure. Is it possible that the bronchoscopy itself added microplastics to the samples?” Devereux wrote in comments posted to the Science Media Centre website.

“The study also cannot tell us how long the microplastic has been in the person’s lung or where it came from. It therefore cannot establish whether microplastics were present before the disease developed or whether differences in the diseased lung affected how particles were deposited or retained,” she added.

In a separate statement, Barbara Hoffmann, MD, MPH, of the University of Düsseldorf, Germany, also reiterated the need for more research on microplastics and lung cancer. “In the meantime, we advocate for the fundamental human right to breathe clean air, and this includes air that is not polluted with microplastics,” said Hoffmann, who is chair of the ERS Advocacy Council and not involved with the study.

Dimeas and colleagues had a study cohort of 100 people split between those with newly diagnosed lung malignancy and controls undergoing bronchoscopy for non-chronic respiratory indications. BAL sampling was performed in all participants, with paired airway tissue sampling done in half the cohort.

Microplastics were detected in 70% of patients and 60% of samples, Dimeas reported.

In those with BAL and tissue samples, overall microplastic detection and total burden were both significantly higher in patients with lung malignancy.

Of note, however, BAL and tissue microplastic burdens were found to have an inverse relationship in those with lung malignancy, suggestive of “compartment-specific pulmonary particle dynamics,” study authors noted.