Air pollution is emerging as a growing problem among risk factors associated with lung cancer deaths

Although deaths from lung cancer and related cancers have decreased in the world’s ten most populous countries between 1990 and 2019, these positive statistics do not take into account trends in mortality due to tobacco use, air pollution and asbestos exposure. These areas need continued policy and research to further reduce deaths, according to a new study from researchers at the Sylvester Comprehensive Cancer Center, part of the University of Miami Miller School of Medicine, and collaborating organizations.

Their study, published in eClinical Medicine, analyzed tracheal, bronchial, and lung cancer (TBL) data from the open-source Global Burden of Disease database.

The results indicated an overall decrease of 8% in TBL cancer deaths over the three-decade period. Although the number of tobacco-related deaths has decreased, it continues to represent the majority of cases. Meanwhile, the death rate from particulate matter air pollution has increased worldwide and asbestos exposure remains a critical concern, especially in the United States.

“This research allows us to better assess global trends and highlight areas where public health policies and further research are needed to address TBL cancers,” said Gilberto Lopes, MD, senior author of the study, head of the Medical Oncology department at Sylvester and his deputy director.

According to the World Health Organization, lung cancer is the leading cause of cancer-related deaths worldwide. The study’s first author, Chinmay Jani, MD, a clinical fellow in hematology and oncology at Sylvester and the Miller School, emphasized the importance of increasing awareness of all risk factors for TBL cancer on a global scale.

The tobacco risk remains

The study found that the percentage of cancer deaths linked to tobacco use fell from 72% in 1990 to 66% in 2019, although certain countries, such as China and Indonesia, continue to experience rising tobacco-related cancer deaths. In addition, the global death rate among women has increased by 2%, although men still account for about three-quarters of deaths from tobacco use.

These trends point to the need to continue public health measures to reduce tobacco use, Jani said. While we are making progress in reducing deaths from tobacco-related lung cancer, the burden remains significant, he said.

“We are going in the right direction, but I feel like the final end of the tunnel is still far away,” Jani added.

Air pollution linked to cancer deaths

Air pollution is now responsible for almost 20% of global TBL cancer deaths.

The total number of deaths from air pollution has decreased between 1990 and 2019, but the number of deaths directly linked to particulate matter in the environment (PM 2.5) has increased by 11%. In China, the rate was twice the global average.

Research fellow Estelamari Rodriguez, MD, MPH, co-leader of the Thoracic Site Disease Group at Sylvester, called for stronger global policies to address this growing threat.

“The link between lung cancer mortality and air pollution is still controversial, but there is increasing evidence that there is a link that needs to be paid attention to,” she said. “This article provides further evidence that this is not an issue limited to one country; it is a global phenomenon.”

Jani also emphasized the need to raise awareness in regions like India, where solid waste burning is common and public awareness of the risk of air pollution remains low.

“The government is trying to provide resources and facilities so that solid waste is disposed of through other means, but public awareness is not that strong among the general population,” he said.

Asbestos remains a problem

Jani presented an earlier phase of the research in April 2024 with MDRCollab, a clinical research group, shortly after the U.S. Environmental Protection Agency finalized a ban on asbestos– one of the most important occupational risk factors for TBL cancer.

This latest analysis included a comprehensive assessment of asbestos exposure, making it the first study to focus on detailed data regarding these three critical risk factors.

Despite significant progress in banning asbestos, the number of deaths from asbestos-related TBL cancer in the U.S. still remains nearly double the global average.

“Although we have banned asbestos, we need to do more research into the causes of exposure,” Jani said.

Further research and improved screening

A key conclusion from the study is the need for continued research to better understand the mechanisms that drive TBL cancer, including how various risk factors contribute to molecular changes in cancer cells.

“Understanding all these risk factors and how they influence the molecular changes of lung cancer is important because we can then have targeted, precise drugs for lung cancer patients based on the risk factors they had,” he said.

The findings also highlighted the need for revision of current screening guidelines, which primarily focus on tobacco exposure. Rodriguez noted an alarming increase in lung cancer diagnoses in younger people, especially in women with low tobacco exposure, raising concerns about the adequacy of current screening practices.

“How can we change the screening approach to be able to diagnose younger patients when they can be cured?” she asked. “Currently, young patients with cough are rarely considered at risk for lung cancer. Their symptoms are often overlooked, even though proper screening could have detected the condition earlier.”