A 44-year-old woman from Pune suffered from persistent chest pain and cough for about six months, with testing failing to reveal the underlying cause. Then a lung sample revealed what she, a nonsmoker, could never have predicted: an advanced stage of lung cancer.
“The woman had never smoked but investigations revealed that genetic mutation was among the underlying causes of adenocarcinoma, a type of cancer that starts in the glands lining your organs. She had progressed to Stage 3B when the cancer spreads to the lymph nodes,” says Dr Mahavir Modi, consulting pulmonologist at Ruby Hall Clinic.
According to a recent study published in Lancet Respiratory Medicine, lung cancer in never-smokers is estimated to be the fifth most common cause of cancer-related mortality globally, happening almost exclusively as adenocarcinoma and predominating in women and Asian populations; exposure to air pollution was linked to nearly 200,000 of those diagnosed with adenocarcinoma.
This case exemplifies the rising trend of lung cancer among women who have never smoked.
“This rising burden of lung cancer is an area of concern as the resultant loss of lives is largely preventable,” says Dr Pankaj Chaturvedi, Director, Advanced Centre for Treatment, Research and Education in Cancer (ACTREC), Tata Memorial Centre, Mumbai.
Lung cancer remains the most common cause of cancer-related illness worldwide, with approximately 2.5 million new cases reported in 2022. Among men, around 1.5 lakh new cases were recorded, with adenocarcinoma contributing to 717,211 cases, making up 45.6% of the total lung cancer burden in males.
In women, an estimated 908,630 new cases of lung cancer were reported globally, with 541,971 cases (59.7%) being adenocarcinoma, Indian Express reported.
At the global level, an estimated 111,486 adenocarcinoma cases among men and 80,378 adenocarcinoma cases among women were attributable to ambient PM pollution.
According to the study, adenocarcinoma accounted for 53%–70% of lung cancer cases among never-smokers worldwide, suggesting that the risk of lung cancer linked to air pollution is on the rise, especially in eastern Asia and China.
“There is accumulating evidence of a causal link between ambient PM pollution and an increased risk of adenocarcinoma. 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,” says Dr Freddie Bray, lead author.
Research suggests that certain genetic variations may increase susceptibility to lung cancer, even in non-smokers. Additionally, hormonal fluctuations, particularly during menopause, may elevate the risk.
Environmental factors also play a significant role—exposure to radon gas indoors or fine particulate matter (PM 2.5) outdoors can alter cellular DNA, affecting cell division and potentially leading to cancer.
In developing nations, prolonged exposure to cooking fumes from wood-burning or frying has also been associated with a higher incidence of lung cancer.
A previous study on the distinct characteristics of lung cancer in Southeast Asia, published in August 2024, led by Dr Chaturvedi and co-authors, revealed that 42% of men and 14.2% of women in the region currently smoke or use smokeless tobacco.
“The rising incidence of teenage smoking, especially in urban areas, is an area of concern. The tobacco industry has exploited every loophole in the regulatory framework to remain profitable. Lack of vendor licensing, low taxes, sale of loose cigarettes and tobacco farming are driving carcinogenic industries,” Dr Chaturvedi says.