A group of respiratory medicine and public health experts are calling for lung cancer in never-smokers to be given greater recognition.
Writing in the Journal of the Royal Society of Medicine, they say that lung cancer in people who have never smoked is under recognised and presents a diagnostic challenge, particularly for GPs seeking to balance over-investigation with early diagnosis and high quality care.
It is estimated that around 6,000 people in the UK who have never smoked die of lung cancer every year, greater than the numbers of people who die of cervical cancer (900), lymphoma (5,200), leukaemia (4,500) and ovarian cancer (4,200).
Major contributors to lung cancers in never-smokers include second-hand smoke, occupational carcinogen exposure and outdoor pollution.
Globally, the use of solid fuels for indoor cooking and second-hand smoke exposure are important contributions to lung cancer in never-smokers and disproportionately affect women.
Lead author, Professor Paul Cosford, Director for Health Protection & Medical Director, Public Health England, said: "This paper demonstrates an estimated 6,000 people who have never smoked die each year from lung cancer in the UK. This makes it, by itself, the eighth most common cause of cancer related death in the UK."
"For too long having lung cancer has only been thought of as a smoking related disease. This remains an important association but, as this this work shows, the scale of the challenge means there is a need to raise awareness with clinicians and policy makers of the other risk factors including indoor and outdoor air pollution."
"This is one reason why PHE published its review of the evidence and recommended specific actions local authorities can take to improve their air quality. By delivering on the promise of a clean air generation we can reduce the number of lung cancers among those who have never smoked."
Co-author Professor Mick Peake, clinical director of the Centre for Cancer Outcomes, University College London Hospitals Cancer Collaborative, said: "Despite advances in our understanding, most people who have never smoked do not believe they are at risk and often experience long delays in diagnosis, reducing their chances of receiving curative treatment."
Prof Peake added: "The stigma of smoking has been the major factor behind the lack of interest in, knowledge of and research into lung cancer. Therefore, in many ways, never-smokers who develop lung cancer are, as a result, disadvantaged."
"Drawing attention to the contribution of underlying risk factors to lung cancer in never-smokers presents opportunities to reinforce efforts to tackle other major public health challenges. For example, the impact of passive smoking and air pollution on lung cancers adds weight to the government's ambitions to improve air quality and the public, clinicians and policy makers must all be aware of this relationship."