Although, as in any other disease process, genetic factors play a role, lung cancer is largely attributable to environmental carcinogens. By far, the most important environmental carcinogen is tobacco smoke. Men begin inhaling large amounts of cigarette smoke during World War I. The incidence of lung cancer among men began a rapid rise 20 years later. An identical but delayed pattern has been observed in women.
In the United States today, the epidemiology of lung cancer is the epidemiology of smoking. Other factors are relatively
Carcinogens in Cigarettes
Cigarette smoke contains a number of problem carcinogens in both the particulate and gaseous phase including:
Risk in Smokers
In general, the risk of developing lung cancer is 10 times greater in male smokers than that of non-smokers. The risk increases with the length of time an individual has smoked, the number of cigarettes smoked daily and the depth of inhalation.
The risk of developing lung cancer is three to five times greater in females smokers than in non-smokers.
Risk After Stopping Smoking
The relative risk of cancer decreases when smoking is discontinued; approximately approaching the level of the non-smoker at 10-15 years. However, it is important to note that the time necessary for decreasing the incidence of lung carcinoma depends on the duration and quantity of cigarette smoking. A person who has smoked for a fewer number of years will have a risk for lung carcinoma equal to the non-smoking population in less that 15 years after smoking cessation.
Filters
There is some evidence in the literature that smoking filtered cigarettes is less hazardous than smoking unfiltered cigarettes, but evidence is spotty at best. There is also concern about potential new harmful effects due to the use of additives in these cigarettes. There is no proof that any cigarette is safe nor is there any substitute for stopping smoking altogether.
A dramatization of the evils of smoking comes from Mr. Yule Brenner (of "The King and I" fame), himself a 4-5 pack per day smoker. When asked if there was any message he would like to leave behind after he was gone he replied, "You must stop smoking now!" In less than a year later, Mr. Brenner was dead of lung carcinoma.