Causes of lung cancer
Anyone can develop lung cancer, but around 90% of cases occur in people who smoke or who used to smoke. Your risk of getting lung cancer increases with the number of cigarettes you’ve smoked and the number of years you’ve been a smoker. If you stop smoking, the risk gets lower over time – after 10 years, your risk of lung cancer falls to half that of a smoker.
Breathing in other people’s smoke over a long period can also increase your risk of getting lung cancer. Other environmental factors, such as exposure to asbestos, can increase the risk as well.
People who’ve never smoked are more likely to develop one particular type of lung cancer called adenocarcinoma.
Lung cancer usually affects people over the age of 60. Younger people can develop lung cancer, but this is rare.