New research reveals a growing trend of lung cancer diagnoses among people who have never smoked, highlighting air pollution as a major risk factor.
Key Points at a Glance:
- Lung cancer in non-smokers is increasing worldwide, now ranking as the fifth leading cause of cancer-related deaths.
- Air pollution is a significant contributor, with 200,000 cases of adenocarcinoma linked to pollution exposure in 2022.
- Adenocarcinoma has become the dominant subtype of lung cancer, especially in East Asia.
- Lung cancer rates among women are rising, narrowing the gap between male and female cases.
- Scientists are urging further research into other potential environmental and genetic risk factors.
A Shift in Lung Cancer Patterns
Lung cancer has long been associated with smoking, but a striking shift is occurring: an increasing proportion of lung cancer cases are now being diagnosed in people who have never smoked. According to the International Agency for Research on Cancer (IARC), non-smokers now account for a growing share of global lung cancer deaths.
One of the most alarming findings is the rise of adenocarcinoma, a subtype of lung cancer that has become the most common in both men and women. In 2022, adenocarcinoma accounted for nearly 46% of lung cancer cases in men and nearly 60% in women, a significant increase from previous years.
The Role of Air Pollution
The study, published in The Lancet Respiratory Medicine, found that air pollution is a major contributor to lung cancer cases in non-smokers. Researchers estimate that in 2022 alone, 200,000 cases of adenocarcinoma were linked to exposure to air pollution. The highest burden was found in East Asia, particularly China, where industrial pollution is a growing concern.
Dr. Freddie Bray, head of IARC’s cancer surveillance branch, emphasized the need for continued monitoring and action. “With declines in smoking rates in countries like the UK and US, the proportion of lung cancers among non-smokers will likely continue to increase. Addressing air pollution must be a priority,” he said.
A Growing Concern for Women
While lung cancer rates in men have generally declined over the past 40 years, incidence rates among women have been rising. In 2022, about 900,000 women were diagnosed with lung cancer, compared to 1.6 million cases in men. Experts predict that the gender gap in lung cancer cases is narrowing, signaling the need for targeted prevention efforts.
In 2023, reports revealed that for the first time, more women in the UK were diagnosed with lung cancer than men, a shift attributed to historical differences in smoking trends. However, experts warn that women should be just as vigilant about lung cancer risks as they are about breast cancer.
Scientists are still working to understand what other environmental or genetic factors might contribute to rising lung cancer rates in non-smokers. While smoking remains the leading cause, air pollution, occupational exposures, and other yet-unknown factors are playing an increasing role.
According to the IARC, air pollution is now considered one of the key drivers behind the increasing dominance of adenocarcinoma, which accounts for up to 70% of lung cancer cases among non-smokers worldwide.
Experts emphasize that stronger policies to reduce air pollution could play a crucial role in lowering lung cancer rates in non-smokers. In addition to anti-smoking campaigns, governments need to implement strategies to monitor and mitigate air pollution, especially in high-risk areas.
“The trends we’re seeing offer important insights for cancer prevention efforts worldwide,” said Bray. “Changes in smoking patterns and environmental exposures must be factored into future lung cancer prevention strategies.”
