Thousands of non-smokers are dying from lung cancer every year because of air pollution and other carcinogens, experts at Public Health England have warned.
Some 6,000 people who have never smoked die in Britain annually from the disease, a larger number than are killed by cervical and ovarian cancer combined.
Yet because lung cancer is still viewed as a disease of smokers, and largely self-inflicted, diagnosis in non-smokers is often late and funding for research is reduced because of the social stigma.
Writing in the Journal of the Royal Society of Medicine, a group of respiratory medicine and public health experts has called for lung cancer in non-smokers to be given greater recognition.
Lead author, Professor Paul Cosford, Director for Health Protection & Medical Director, Public Health England, said: “For too long having lung cancer has only been thought of as a smoking related disease. “This remains an important association but, as 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.”
Major contributors to lung cancers in non-smokers include second-hand smoke, occupational carcinogen exposure, and air pollution from cooking, transport and industry.
Lung cancer accounts for around 13 per cent of all cancers in Britain and 22 per cent of cancer deaths, with around 42,000 new cases identified every year, and around 35,000 deaths.
But it receives just £400 research funding per death, compared with breast cancer which gets £3,500, which has led to virtually no improvement in survival rates in the last 50 years. At the beginning of the 1970s just three per cent of people survived for 10 years and today it is around five per cent. In the same time survival for breast cancer rose from 40 per cent to 78.5 per cent.
Women are also disproportionately affected with studies showing that one in five women who develop lung cancer have never smoked, compared to one in 10 men.
And lung cancer among non-smokers appears to be rising. The proportion of non-smokers undergoing surgery for lung cancer jumped from 13 per cent to 28 per cent from 2008 to 2014.
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.
“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.
"It is our estimate that at least 450 people who have never smoked die of lung cancer per year as a result of outdoor air pollution.
"Smoking rates continue to fall, so I guess there could come a point in the future when lung cancer in non-smokers might overtake smoking-related lung cancers, though that is some way off."