This page tells you about risks and causes of lung cancer. You can find information about
- A quick guide to what’s on this page
- How common lung cancer is
- Smoking and lung cancer
- Other risk factors
- Protecting against lung cancer
Smoking and lung cancer
By far the biggest cause of lung cancer is smoking. It causes more than 8 out of 10 cases (86%) including a small proportion caused by exposure to second hand smoke in non smokers (passive smoking).
Here are some facts about smoking and lung cancer
- The more you smoke, the more likely you are to get lung cancer but the length of time you have been a smoker is even more important than how many cigarettes you smoke a day
- Starting smoking at a young age is even more harmful than starting as an adult
- Stopping smoking reduces your risk of lung cancer compared to continuing to smoke. The sooner you quit, the better your health – but it’s never too late
- Passive smoking (breathing in other people’s cigarette smoke) increases the risk of lung cancer, but it is still much less than if you smoke yourself
It is almost impossible to work out the risk of occasional passive smoking. We know that the risk of lung cancer for passive smokers goes up the more cigarette smoke they are exposed to. Overall, people exposed to environmental tobacco smoke at work or at home have their risk of lung cancer increased by about a quarter compared to people who are not exposed to it. Heavy exposure to environmental tobacco smoke at work has been shown to double the risk of lung cancer.
Cigarette smoking is the main cause of lung cancer. But pipe and cigar smokers are still much more likely to get lung cancer than non smokers. They are also much more likely to get cancer of the mouth or lip.
In the past, lung cancer has been more common in men than women. Now, because more women smoke, it is almost as common in women.
Other risk factors
Some other things increase lung cancer risk. But they increase the risk by only a small amount and far less than smoking. They are
- Exposure to radon gas
- Exposure to certain chemicals
- Air pollution
- Previous lung disease
- A family history of lung cancer
- Past cancer treatment
- Previous smoking related cancers
- Lowered immunity