RE: "INTERACTION BETWEEN TOBACCO AND ALCOHOL CONSUMPTION AND THE RISK OF CANCERS OF THE UPPER AERO-DIGESTIVE TRACT IN BRAZIL"

Abstract

Schlecht et al. (1) continue the same long-standing confusion in interpretation of the data on the relation of smoking and drinking as independent risk factors for cancer of the upper aero-digestive tract (UADT). They studied 784 patients with cancer of the oral cavity, pharynx, and larynx for smoking and drinking habits and other characteristics. Since virtually all of these cases both smoked and drank, the authors used statistical methods in an attempt to determine the effect of each of these two habits. This is the same method that has been used in many other, similar studies, leading some to conclude that drinking is an independent risk factor. However, this is very problematic since other biologic data show that, although potent carcinogens exist in tobacco smoke, alcohol is not a carcinogen. Consequently, the most often used explanation for an effect of alcohol is that it increases the permeability of the carcinogens from tobacco. This is entirely different from an implication that alcohol is an independent carcinogen.