Lung cancer is no longer a disease confined to smokers. At the Kidwai Memorial Institute of Oncology in Karnataka, 836 of 13,576 new cancer cases diagnosed in 2025 were lung cancers, accounting for 6.1% of the institute’s total burden, and 260 of those patients were women. Oncologists in Bengal report that roughly one-third of lung cancer patients they treat have no history of tobacco use, and a Kuala Lumpur surgeon notes that about half the patients he operates on are non-smoking Chinese women. The shift is challenging the long-held perception that lung cancer is primarily a smoker’s disease.

Fine particulate matter, especially PM2.5, penetrates deep into the lungs and causes chronic inflammation and DNA damage, according to Shyam Krishnan, a pulmonologist at CMRI Hospital in Kolkata. Indoor air pollution from cooking fumes, biomass fuels and mosquito coils compounds the risk, particularly for women. A study from Clalit-Soroka University Medical Center and Ben-Gurion University found that children whose parents smoke only outdoors still had measurable levels of cotinine, a nicotine metabolite, in their urine, and those with higher exposure experienced 67% more nighttime arousals. “The only effective way to eliminate children’s exposure to tobacco smoke is to maintain completely smoke-free homes and vehicles,” said Prof. Ariel Tarasiuk, who led the research. Genetic mutations, possibly triggered earlier by pollution or stress, are also being detected more frequently in non-smokers and women.

Despite the broadening risk profile, screening uptake remains low. In the United States, only about a quarter of eligible patients were up to date with annual low-dose CT scans in 2024, even though a landmark 2011 trial showed a 20% reduction in lung-cancer deaths and a 2019 Italian study reported a 39% reduction after ten years. Eligibility criteria—age 50 to 80, a 20 pack-year smoking history, and current smoking or having quit within 15 years—are often difficult for patients and physicians to calculate. Meanwhile, symptoms such as persistent cough, weight loss and shortness of breath are frequently misattributed to other conditions, delaying diagnosis. A retired teacher in Brazil consulted more than ten doctors over six months before her metastatic lung cancer was identified, despite telling each that she smoked two packs a day.

“Malaysia must quickly adopt a whole-of-healthcare approach involving primary care and the private sector, and work collectively towards a national screening programme,” said Dr Anand Sachithanandan, a cardiothoracic surgeon recently elected to the global advisory council of the International Association for the Study of Lung Cancer. The next milestone to watch is whether health systems can translate the evidence on environmental and genetic risk into broader screening eligibility and public awareness campaigns that reach non-smokers and younger adults.