Summary
Lung cancer cases in never-smokers are increasing, driven by air pollution and genetic mutations, particularly affecting women and younger patients.
Lung cancer in people who have never smoked is becoming more common, representing 10-20% of all lung cancer cases worldwide. This type of cancer is different from smoking-related lung cancer and affects different groups of people in unique ways.
Never-smoker lung cancer primarily affects women, who are twice as likely to develop the disease compared to men who never smoked. It also tends to occur in younger patients – when doctors see lung cancer in people aged 30-35, they are usually never-smokers. The cancer type is almost always adenocarcinoma, which starts in mucus-producing cells, rather than the squamous cell type more common in smokers.
Air pollution is the second leading cause of lung cancer after smoking. Tiny particles called PM2.5, found in vehicle exhaust and fossil fuel smoke, play a major role. These particles don’t directly damage DNA like cigarette smoke does. Instead, they wake up dormant cancer cells that carry genetic mutations, particularly the EGFR mutation that’s more common in women, especially those of Asian descent.
Indoor air pollution also contributes to risk. Cooking fumes, wood-burning stoves, and poorly ventilated spaces increase lung cancer risk, particularly affecting women who traditionally spend more time indoors. Radon exposure and secondhand smoke are additional risk factors.
The good news is that treatment has dramatically improved. Targeted drugs that block specific genetic mutations have extended survival from less than 12 months twenty years ago to several years today. Some patients have been on targeted therapy for over 10 years.
However, 99% of the world’s population lives in areas where air pollution exceeds WHO guidelines. Climate change and wildfires are making air quality worse in some regions, potentially increasing future lung cancer cases in never-smokers.
