Study of Global Lung Cancer Deaths Points to Emerging Trends and Effects on Women
Article Summary
- A new Sylvester study takes a look at global mortality from lung and related cancers due to tobacco and air pollution.
- After years of decline, estimated mortality rates from tobacco and air pollution are leveling off or even increasing in some countries, including the U.S.
- Tobacco is by far still the biggest killer, but deaths from air pollution show concerning trends, especially in women.
A new study examines the causes of lung and related cancers in the 10 most populous nations, including the U.S. The findings, by researchers at Sylvester Comprehensive Cancer Center, part of the University of Miami Miller School of Medicine, reveal an evolving picture of global mortality from tracheal, bronchial and lung cancers (TBLC) from 1990 to 2019. The data also put the spotlight not only on tobacco use but on air pollution.
“Tobacco smoking is still the most important modifiable risk factor, but air pollution has become a very important risk factor as well,” said senior author Gilberto Lopes, M.D., chief of the Division of Medical Oncology at Sylvester and associate director for the cancer center.
The data highlights the need to tailor public health measures to women, who are increasingly affected by lung cancer. Globally, TBLC mortality from tobacco and air pollution decreased by 17% for males but increased 15% for females during the study period. Males still account for the majority of deaths from both causes.
The ongoing study was presented by Chinmay Jani, M.D., a Sylvester clinical fellow in hematology and oncology, at the annual meeting of the American Association for Cancer Research (AACR). Dr. Jani won an AACR Scholar-in-Training Award for his presentation.
The findings “underscore the complex interplay of societal and environmental factors in lung cancer mortality,” said Dr. Jani. He speculated that women may have been more recently affected as they became more mobile and involved in society.
The Big Killers
Decades of research have shown with clarity that lung cancer is a major killer. It is the leading cause of cancer-related deaths worldwide and tobacco is responsible for the majority of these cases. In the U.S. alone, 20.8% of all cancer deaths in 2023 were attributable to lung or bronchus cancer, according to the National Cancer Institute.
Many countries have implemented public health measures to curb tobacco use in the last decades, bolstered by the World Health Organization Framework Convention on Tobacco Control. The result has been a global decrease in mortality from TBLCs, driven in large part by a reduction in tobacco use by men. Reduced tobacco use is reflected in reduced mortality rates a decade or two later, said Dr. Jani.
Dr. Jani and his colleagues examined the data granularly, crunching the numbers in the open-source Global Burden of Disease database from the Seattle-based Institute for Health Metrics and Evaluation. The database includes mortality data from TBLCs linked to estimates of their cause from tobacco or air pollution.
Below are some additional highlights from the study:
- Countries with long-term or recent increases in female tobacco-related TBLC mortality include China, Indonesia, Russia, India, Bangladesh and the U.S., reflecting a global increase in this population. Some of these data are not statistically significant but do show a trend.
- Several countries also show recent estimated increases in male, tobacco-related TBLC mortality after years of decline. These countries include the U.S., Indonesia and Bangladesh.
- Global TBLC mortality rates in females due to air pollution also increased slightly around 2017 after years of decline, particularly in Bangladesh, India, Pakistan, Nigeria and China. Similarly, U.S. TBLC mortality rates due to air pollution stopped decreasing in 2017 for both females and males and show a slight recent uptrend for males.
- Overall, the U.S. had the highest tobacco-related TBLC mortality rate in 1990 and China had the highest in 2019. China had the highest mortality rate from air pollution throughout the study period. In Indonesia, tobacco-related TBLC deaths for men and women have risen steadily since 1990.
- The proportion of global TBLC deaths unrelated to tobacco or air pollution rose globally to about 30% by 2019. Dr. Jani said possible causes include hereditary and genetic factors, though more research is needed.
Future Directions
While global TBLC death rates from both tobacco and air pollution declined sharply from 2004 to 2017, the recent leveling off or increases in some countries is “alarming,” said Dr. Jani. The slight increases emerged when new targeted therapeutics should have taken the edge off the mortality rates, noted Dr. Jani. The study also highlights the need to reduce air pollution, especially in developing countries and China.
The researchers would also like to see more studies about what specific constituents in air pollution might trigger disease and what genetic changes might result. Previous studies have shown a link between fine particulate matter in the air and a subtype of lung cancer called EGFR-mutant non-small cell lung cancer, which targeted therapies can treat, said second author Samuel Kareff, M.D., Sylvester chief hematology and oncology clinical fellow.
The researchers plan to drill further into the causes of TBLC mortality in the future, with one aim being to inform public health interventions. Dr. Kareff notes that climate change risks increasing air pollution, such as wildfires.
“These data bolster the imperative that public health and other national and international authorities have to curtail emissions production in order to improve the health and well-being of their populations,” said Dr. Kareff. “These trends will not be reversed without major collaborative action.”
Tags: Dr. Gilberto Lopes, global health, lung cancer, Sylvester Comprehensive Cancer Center