Cigarette smoking is the biggest single cause of lung cancer
Over 80% of lung cancer is caused by smoking and the risk increases the longer a person has smoked and the more cigarettes per day they smoke.
There is a greater risk to those who started smoking at an early age and stopping smoking reduces the risk, even in those who have smoked for years.
Passive smoking (breathing in other people’s smoke) increases the risk of lung cancer but it is much less than in those who smoke. Pipe and tobacco smokers have a higher risk of lung cancer than non-smokers and are also at risk of mouth or lip cancer.
There are some other risk factors but they increase the risk by a much smaller amount than smoking. These include:
- · Exposure to radon gas (naturally occurring radioactive gas in rocks and soils)
- · Exposure to some occupational dusts and chemicals (e.g. asbestos and diesel fumes)
- · Previous scarring in the lungs (eg from TB)
- · Family history of lung cancer
- · Previous cancer treatments such as radiotherapy
- · Reduced immunity (such as in HIV/AIDS or in those taking immunosuppressive drug treatments).