Cigarette smoking is known to be the cause of most lung cancers. Lung cancer can also develop in people who do not smoke, although this is much rarer. The risk of developing lung cancer increases with the number of cigarettes smoked, and if people started smoking at a young age. Filtered and low-tar cigarettes may slightly reduce a person’s risk of developing cancer, but the risk is still far greater than that of a non-smoker.

Lung cancer has always been more common in men, particularly those over 40, as more men used to smoke than women. However, as more women have started smoking, the number of women developing lung cancer has gone up considerably.

Stopping smoking

If a person stops smoking, the risk of lung cancer falls quite quickly, and after about fifteen years, that person’s chances of developing the disease are similar to those of a non-smoker.

Passive smoking

It now appears that breathing in other people’s cigarette smoke, known as passive smoking, slightly increases the risk of lung disease and cancer, although the risk is still much less than if you smoke yourself.

Cannabis

Smoking cannabis may also increase the risk of lung cancer. Although less is known about the harmful effects of smoking cannabis, it is believed to cause similar damage to the cells in the lungs as smoking tobacco.

Pipes and cigars

Although pipe and cigar smokers have a lower risk of lung cancer than cigarette smokers, they are at a much greater risk than non smokers.

In some families, smokers may be more likely to develop lung cancer due to inherited faulty genes. At present, we do not know what these genes are.

People who have been in prolonged or close contact with asbestos have a higher risk of lung cancer, especially if they smoke. Asbestos and tobacco smoke act together to increase the risk. Many people have been in contact with asbestos during their working lives. Low-level exposure increases the risk of lung cancer only slightly, compared to the risk from smoking, while heavy exposure may result in a much higher risk of lung cancer. Asbestos exposure also increases the risk of mesothelioma, a cancer of the membranes which cover the lungs.

If you have worked with asbestos and developed lung cancer, you may be able to claim compensation or be paid Industrial Injuries Disablement Benefit. You can get more advice about this from your cancer doctor or from support organisations.

In some parts of the UK, such as the West Country and the Peak District, a naturally occurring gas called radon can pass from the soil into the foundations of buildings. It is now thought that this gas, in high concentrations, may increase the risk of developing lung cancer. If you are worried about this, you can get a radon detector to measure the level of radon in your house, from the radiation protection division of the Health Protection Agency. They can also advise you on what you can do to reduce the risk.

Contact with certain chemicals and substances – such as uranium, chromium and nickel – can cause lung cancer, but these are very rare causes. Air pollution has been suggested as a cause of lung cancer, but this is difficult to prove.

Lung cancer is not infectious and cannot be passed on to other people.