Lung cancer rates in people who have never smoked are rising, with the disease now accounting for 10-20% of all diagnoses worldwide. Unlike smoking-related lung cancer, this form is almost exclusively adenocarcinoma, which starts in mucus-producing cells. According to oncologist Andreas Wicki of University Hospital Zurich, it is a separate disease entity with unique molecular characteristics that influence treatment and outcomes.
Non-smokers diagnosed with lung cancer tend to be younger than smokers with the disease, with many cases appearing in those aged 30-35. Women are more than twice as likely as men to develop lung cancer without a smoking history. A key factor is the presence of 'driver mutations' such as EGFR, which are more common in women, particularly of Asian descent. Early evidence suggests female hormones and genetic variants affecting oestrogen metabolism may play a role.
Diagnosis often occurs at advanced stages (3 or 4) because early symptoms like persistent cough, chest pain, or breathlessness are easily dismissed. The strong historical link between smoking and lung cancer can lead non-smokers to overlook symptoms. Martha, a 59-year-old non-smoker, was diagnosed with stage IIIA lung cancer after her cough changed and mucus thickened. She had never considered herself a smoker, having only occasionally lit up at parties.
While smoking-related lung cancers remain the majority, declining smoking rates globally have shifted the proportion of cases in never-smokers upward. The pharmaceutical industry has responded to the discovery of driver mutations, developing targeted therapies that have improved outcomes for some patients. However, further research is needed to understand the causes and improve early detection in this growing patient group.
