The incidence of lung cancer among never-smokers is increasing worldwide. What are the underlying causes?
The incidence of cancer among individuals who have never smoked is on a steady rise. Air pollution is identified as a major contributing factor in this trend. This information has been reported by the International Agency for Research on Cancer (IARC), a part of the World Health Organization. According to IARC statistics, lung cancer among non-smokers is now recognized as the fifth leading cause of cancer-related mortality globally.
IARC indicates that the predominant type of lung cancer in non-smokers is adenocarcinoma, which is one of the four subtypes of lung cancer.
A research report from IARC, published in the Lancet Respiratory Medicine journal, reveals that in 2022, approximately 200,000 individuals were exposed to air pollution and subsequently developed adenocarcinoma.
The study highlighted a stronger correlation between air pollution and adenocarcinoma in East Asia, particularly in China.
Freddie Bray, the lead author of the study and head of the IARC's cancer surveillance branch, stated to the Guardian that the findings indicate an urgent need to address the evolving patterns of lung cancer risk. He emphasized that if smoking is not the primary cause of lung cancer, further investigation is essential to uncover other potential causes, including air pollution.
Lung cancer affects a substantial number of individuals worldwide. In 2022, around 2.5 million people received a lung cancer diagnosis globally.
The primary classifications of lung cancer include adenocarcinoma, squamous cell carcinoma, small cell carcinoma, and large cell carcinoma. According to the International Agency for Research on Cancer (IARC), adenocarcinoma is the predominant type affecting both genders.
In 2022, adenocarcinoma was diagnosed in 45.6 percent of men and 59.7 percent of women with cancer. This represented an increase from 39 percent for men and 57.1 percent for women in 2020.
The IARC reported that 70 percent of individuals who developed lung cancer without a history of smoking were diagnosed with adenocarcinoma.
While the incidence of lung cancer among men has decreased in many countries over the past four decades, the rate among women has shown a consistent upward trend.
In 2022, approximately 1.6 million men were diagnosed with lung cancer, maintaining a majority among cases. However, the disparity between lung cancer rates in women and men is diminishing, with around 900,000 women diagnosed that year.
A 2023 report from the Guardian indicated that, for the first time in the UK, the number of women diagnosed with lung cancer surpassed that of men. Consequently, women were urged to be as vigilant regarding lung cancer as they are for breast cancer.
Cancer specialists emphasize that women should seek medical evaluation if they notice any unusual changes, such as lumps in their breasts, and should also be aware of the symptoms associated with lung cancer.
The global percentage of individuals who have never smoked and subsequently develop lung cancer remains unclear, although evidence suggests that this phenomenon is on the rise. Researchers are actively investigating additional causes of lung cancer beyond smoking.