Researchers have shed light on why individuals who don’t smoke are increasingly being diagnosed with lung cancer, and their findings may be unexpected.
Lung cancer ranks as the third most prevalent cancer in the United States. According to the Lung Cancer Research Foundation, one out of every sixteen Americans will face a lung cancer diagnosis at some point in their lives. Although tobacco smokers are at a higher risk, there are other potential contributors to the disease.
Scientists suggest another underlying reason for the rise in lung cancer cases worldwide among non-smokers.
In alignment with World Cancer Day on February 4, specialists from the International Agency for Research on Cancer (IARC) shared insights from a recent study published in the esteemed Lancet Respiratory Medicine journal.
The research paper, titled ‘Estimated worldwide variation and trends in incidence of lung cancer by histological subtype in 2022 and over time: a population-based study’, utilized data from the Global Cancer Observatory (GLOBOCAN) 2022, Cancer Incidence in Five Continents Volumes VII–XII, and contributions from the African Cancer Registry Network.
The study calculated ‘country-specific, sex-specific, and age-specific proportions of and sex-specific and age-specific incidence rates per 100 000 people for all four histological subtypes.’
The four subtypes analyzed were adenocarcinoma, squamous cell carcinoma [SCC], small-cell carcinoma, and large-cell carcinoma.
Adenocarcinoma, which is the most frequent subtype, emerged as the fifth leading cause of cancer-related deaths globally among individuals who have never smoked.
The findings revealed that in 2022, there were approximately 1.6 million new lung cancer cases in men and 909,000 in women, despite a global decline in smoking rates.
The researchers asserted that air pollution is likely the main contributor to these specific lung cancer cases.
“Air pollution can be considered an important factor that partly explains the emerging predominance of adenocarcinoma that accounts for 53% to 70% of cases of lung cancer among people who have never smoked worldwide,” the study states.
Dr. Freddie Bray, head of the IARC’s cancer surveillance branch and lead author of the study, elaborated on the evolution of lung cancer: “The results provide important insights as to how both the disease and the underlying risk factors are evolving, offering clues as to how we can optimally prevent lung cancer worldwide.
“Changes in smoking patterns and exposure to air pollution are among the main determinants of the changing risk profile of lung cancer incidence by subtype that we see today.
“The diverging trends by sex in recent generations offer insights to cancer prevention specialists and policy-makers seeking to develop and implement tobacco and air pollution control strategies tailored to high-risk populations.”
Following the release of the study, the IARC emphasized the need for more research into how air pollution and other potential factors contribute to lung cancer.
You can access the complete study here.