Risks and causes

There are some factors that can increase your risk of developing lung cancer.

The risk factors for lung cancer are explained below. Having any of these risk factors doesn't mean that you will definitely get cancer.

Risks and causes

Smoking tobacco is the biggest cause of lung cancer in the UK. Around 7 out of 10 lung cancers are caused by smoking. This includes breathing in other people’s cigarette smoke.

Even light or occasional smoking increases the risk of lung cancer. But your risk increases more the longer you smoke and the more you smoke. Stopping smoking is the best thing you can do for your health. The sooner you stop, the better.

Some substances increase the risk of lung cancer. These include asbestos, silica, and diesel exhaust. People can be exposed to these through their work.

Asbestos was used in shipbuilding and the construction industry in the 1960’s. Even though the use of asbestos was banned in the UK in 1999, some construction workers in older buildings might still be exposed to it. There are strict laws about work that involves asbestos: for example, when working in or repairing structures containing asbestos. Smoking increases the risk from asbestos exposure.

Silica is a substance used in some construction and material industries such as glass making and bricklaying. People who have worked as bricklayers can have a slightly increased risk of lung cancer. It can cause a condition known as silicosis, which increases the risk of lung cancer. 

Diesel engine exhaust fume exposure increases the risk of lung cancer. So, people who are regularly exposed to exhaust fumes through their jobs have a higher risk of developing lung cancer. This includes professional drivers and mechanics.

We know that air pollution can cause lung cancer. The risk depends on the levels of air pollution you are regularly exposed to. At UK levels, the extra risk for each person is likely to be small. The exposure to outdoor air pollution causes around 1 out of 10 (10%) lung cancer cases in the UK.

Previous lung diseases can increase your risk of lung cancer. These risks are usually higher in smokers.

Chronic obstructive pulmonary disease (COPD) is also called chronic obstructive airways disease. It means long term lung illnesses such as emphysema and chronic bronchitis.  COPD usually develops because of long-term damage to your lungs from breathing in a harmful substance, usually cigarette smoke. Your risk of lung cancer is higher if you have COPD or lung infection (pneumonia) compared to people who don’t have it.

Radon gas is a naturally occurring radioactive gas that comes from tiny amounts of uranium present in all rocks and soils. Radon gas can build up in homes and other buildings. The highest levels are in south west England but higher than average levels may be found in many other parts of the UK. 

Exposure to radon causes a small number of lung cancers in the UK. The risk increases if you smoke. So, it’s even more important to stop smoking if you live in a high radon area.

Your risk of lung cancer is higher if you have a close relative (such as a parent or sibling) who has had lung cancer.

Researchers are looking at how our genes could affect our risk of lung cancer.

Other possible causes

Stories about potential causes of cancer are often in the media and it isn’t always clear which ideas are supported by evidence. There might be things you have heard of that we haven’t included here. This is either because there is no evidence about them or the evidence is unclear.

Get detailed information about lung cancer risks and causes

  • The fraction of cancer attributable to known risk factors in England, Wales, Scotland, Northern Ireland, and the UK overall in 2015
    KF Brown and others
    British Journal of Cancer 2018. Apr;118(8):1130-1141

  • Preventable exposures associated with human cancers
    VJ Cogliano, R Baan, K Straif and others
    Journal of the National Cancer Institute, 2011. Dec 21;103(24):1827-39

  • Increased risk of lung cancer in individuals with a family history of the disease: a pooled analysis from the International Lung Cancer Consortium
    ML Cote, M Liu, S Bonassi and others
    European Journal of Cancer, 2012 Sep;48(13):1957-68

  • Lung cancer risk among bricklayers in a pooled analysis of case-control studies
    C Consonni, S De Matteis, AC Pesatori and others
    International Journal of Cancer, 2015 Jan 15;136(2):360-71

  • Cancer Principles and Practices of Oncology (11th Edition)

    V.T Devita, T.S Lawrence and S.A Rosenberg

    Wolters Kluwer, 2019

  • The information on this page is based on literature searches and specialist checking. We used many references and there are too many to list here. Please contact patientinformation@cancer.org.uk with details of the particular issue you are interested in if you need additional references for this information.

Last reviewed: 
10 Oct 2019