Comparative epidemiology of tobacco-related cancers.

In a retrospective study, interviews were obtained with 3,716 patients with histologically proven cancer of the lung (Kreyberg types I and II), mouth, larynx, esophagus, or bladder and with over 18,000 controls. For each of these cancers, the relative risk of both male and female present smokers increased with the quantity smoked and the duration of the habit. The strongest increase occurred for cancer of the lung and larynx, and the least increase occurred for cancer of the esophagus and bladder. For exsmokers the risk decreased with years of cessation. The risk for mouth cancer of pipe and cigar smokers who inhaled much less than cigarette smokers was less than that of the latter and increased with the quantity smoked. The risk of mouth, larynx, and esophagus cancer among smokers increased with the quantity of alcohol consumed. Greater smoking habits and lesser cessation rates were noted among lower socioeconomic groups, suggesting that these groups will bear an ever increasing proportion of the burden of tobacco-related cancer.