Lung cancer is largely attributable to environmental carcinogens. By far, the most important environmental carcinogen is tobacco smoke. Men began smoking cigarettes during World War I. The incidence of lung cancer among men began a rapid rise 20 years later. An identical but similar delayed pattern has been observed in women.

Today, the epidemiology of lung cancer is the epidemiology of smoking. Other factors are relatively of minor importance.

Cigarette smoke contains a number of proven carcinogens in both the particulate and gaseous phase including:
-Aromatic Hydrocarbons
Exposure to certain substances have a synergic effect in being causatively associated with the use of tobacco products in development of lung cancer.
-Chloromethyl Ethers
-Mustard Gas
-Radioactive Ore
Host Factors
As with most illnesses, the development of disease depends on a complex interaction between the environment and the host. Specifically with lung cancer, host factors play a relatively minor role.
-Risk of Second Primary
-Associated Malignancies
-Aryl Hydrocarbon Hydroxylase
-Scar Carcinoma