Around 6,000 people who have never smoked die of lung cancer every year, often because they have been exposed to carcinogens in the workplace, air pollution or second-hand smoke.
According to research published in the Journal of the Royal Society of Medicine, occupational carcinogen exposure accounts for 20.5% of lung cancers in non-smoking men and 4.3% of lung cancers in non-smoking women.
Although the research claims that the precise causes of lung cancer in non-smokers are difficult to determine due to the “overlapping and ubiquitous nature of risk factors and exposures”, it estimates that inhaling second-hand smoke accounts for around 15% of cases; outdoor pollution contributes to 8%, and X-ray radiation accounts for 0.8%.
The number of “never smokers” – those who have smoked less than 100 cigarettes in their lifetime – that die of lung cancer every year is greater than the numbers of people who die from cervical cancer (900), lymphoma (5,200), leukaemia (4,500) and ovarian cancer (4,200).
However, smoking remains the largest modifiable risk factor for lung cancer and accounts for 86% of lung cancers in the UK, the research paper adds.
One of the authors, Professor Paul Cosford, Public Health England’s director for health protection and medical director, is a non-smoker with lung cancer. He told The Guardian newspaper: “People will find these numbers very surprising. They rarely think of lung cancer as a non-smoker’s disease. They’re so focused on smoking as the main risk factor that we forget that there are quite a few causes of lung cancer that affect non-smokers.
“From a personal perspective, when I knew I was ill I never thought I would have lung cancer as I wasn’t a smoker. There’s an emerging realisation that this is a health problem we need to get supportive about.”
Richard Steyn, a consultant thoracic surgeon in the NHS and the chair of the UK Lung Cancer Coalition, said: “Apart from avoiding passive smoke, areas of high air pollution and wearing protective breathing apparatus in specific occupations, there is not a great deal that someone who does not smoke can do to avoid the risk.”
In order to speed up diagnosis and improve health outcomes, he said health professionals need to be more aware of the fact that people who have never smoked are also at risk of lung cancer.
“Many patients who have never smoked who develop lung cancer have their diagnosis delayed because of this lack of recognition so many of them have very advanced disease by the time they get to specialist care,” he added.