What causes lung cancer?

• Cigarette smoking is known to be the cause of most lung cancers. The risk of developing the disease increases with the number of cigarettes smoked, and if people start to smoke at a young age. Filtered and low tar cigarettes may reduce the person’s risk of developing cancer slightly, but it is still far greater than that of a non-smoker. Lung cancer has always been more common in men, particularly those over the age of 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.
• If a person stops smoking, the risk of lung cancer goes down quite quickly and after about fifteen years that person’s chances of developing the disease are similar to that of a non-smoker.
• 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.
• Smoking cannabis may also increase the risk of lung cancer.
• 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 an inherited faulty gene.
• 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.
• 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 have your house checked by the National Radiological Protection Board, which can 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