Possible causes of lung cancer

There are four major causes of lung cancer (and cancer in general):

• Carcinogens such as those in cigarette smoke
• Radiation exposure
• Genetic susceptibility
• Viral infection

Cigarette smoking

Lung cancer is directly related to smoking.

It is proven that there are over 40 carcinogens in the cigarette smoke including radioisotopes from the radon decay sequence, nitrosamine, and benzopyrene. Additionally, nicotine appears to depress the immune response to malignant growths in exposed tissue.

Unfortunately, the risk of getting cancer is not removed immediately after you stop smoking. In fact up to 40% of newly diagnosed lung cancer occurs in former smokers. In the United States, smoking is estimated to account for 87% of lung cancer cases.

Exposure to asbestos and certain chemicals

• Asbestos has been known to increase the risk of getting lung cancer.
• Uranium, chromium and nickel can all cause lung cancer too. 

 Exposure to radon gas

Radon gas is a naturally occurring radioactive gas that can seep out of the soil into buildings. It is thought that radon gas in very high concentrations may cause lung cancer.

Air pollution

Air pollution may cause lung cancer, although this has only been proven in people exposed to large amounts of diesel exhaust fumes for many years through their work. This type of long term occupational exposure may increase lung cancer risk by up to 47%. 

Genetic susceptibility

Experts are still looking into the impact of family history on lung cancer. There is some evidence that there is at least one lung cancer gene because family history of lung cancer does have an impact on the risk. Families of smokers will all be exposed to cigarette smoke and so have an increased risk of lung cancer whether they carry the gene or not.

Passive smoking

Passive smoking refers to inhalation of the smoke coming from someone else’s cigarette. It has recently been identified as a much more possible cause of lung cancer in non-smokers than previously believed. Several researches have been conducted on this subject and they all came to the same conclusion- passive smoking causes lung cancer in non-smokers.

The study found that there was an estimated 16% increased risk of lung cancer among the non-smoking spouses of smokers. It is estimated that workplace exposure increases the risk for 17%.