Smoking and lung cancer: an overview.

This position paper summarizes the overwhelming evidence that tobacco smoking is the cause of 30 to 40% of deaths from cancer. The focus is on lung cancer because of the sheer magnitude of this disease in males and the likelihood of a similar epidemic in females. There are two categories of evidence that indicate smoking to be the major cause of human lung cancer. Without exception, epidemiological studies have demonstrated a consistent association between smoking and lung cancer in men and now suggest a similar association in women. Chemical analyses of cigarette smoke reveal a multitude of known mutagens and carcinogens. Moreover, these chemicals are absorbed, are metabolized, and cause demonstrable genetic changes in smokers. Two consequences of smoking are evaluated. The results of treatment of lung cancer are not encouraging; despite vigorous therapy, the 5-year survival rate remains less than 10%. The social and economic costs of lung cancer and the smoking habit impinge on the productiveness of our society.