The mystery rise of lung cancer in non-smokers

Lung cancer is traditionally linked to smoking, but a growing number of cases are now being diagnosed in people who have never smoked. This trend has puzzled doctors and researchers, as lung cancer in non-smokers appears to be a distinct disease with different causes and characteristics. Martha, a 59-year-old woman, experienced a persistent cough and thick mucus, which she initially thought was related to a rare lung disorder she had. However, after an X-ray revealed a shadow on her lung, further tests confirmed she had lung cancer. Despite occasionally smoking at parties, Martha never considered herself a smoker, making her diagnosis a shock.

Globally, lung cancer remains one of the most common and deadliest cancers, with millions diagnosed each year. While smoking-related lung cancers still make up the majority of cases, smoking rates have declined in many countries. As a result, the proportion of lung cancer cases in never-smokers is rising, now accounting for about 10 to 20 percent of diagnoses. Lung cancer in never-smokers tends to affect younger patients and is more common in women. The most common type in these patients is adenocarcinoma, which starts in mucus-producing cells, unlike the squamous cell carcinoma more common in smokers. Unfortunately, lung cancer is often diagnosed late because early symptoms like coughing and chest pain are mild or mistaken for other illnesses.

Research has shown that lung cancer in never-smokers is often driven by specific genetic mutations, such as the EGFR mutation, which is more prevalent in women and people of Asian descent. Scientists are still investigating why these mutations occur more frequently in certain groups. Environmental factors also play a role; exposure to indoor air pollution from cooking fuels and outdoor air pollution, especially fine particulate matter known as PM2. 5, increases lung cancer risk. Studies suggest that air pollution may not directly cause DNA mutations but can activate dormant mutated cells, promoting tumor growth. Advances in targeted therapies that block the effects of these mutations have improved survival rates significantly. However, prevention efforts focusing on reducing air pollution and other risk factors remain crucial to combat the rising incidence of lung cancer in non-smokers.