Smoking and cancer: Retrospective studies and epidemiological evaluation

Abstract

1. 1. The chemical and biological properties of tobacco smoke condensate are sufficient to classify it among other chemical carcinogens. 2. 2. Human retrospective studies are consistent with the hypothesis that exposure to this material increases the incidence of malignant tumors of the lung, larynx, mouth, bladder and esophagus in man. 3. 3. No single mechanism of carcinogenesis is postulated by these data, as is true of other etiological observations in carcinogenesis. 4. 4. From the clinical and public health viewpoint these data fully justify acceptance of an effective etiological relation between smoking and malignant tumors, particularly of the respiratory tract. This conclusion has been reached by a number of official and voluntary scientific bodies and by national and state public health agencies [16–18]. As in the interpretation of any body of evidence, it is possible to suggest alternative hypotheses, and in so doing we may gain new insight into some of the basic problems relating to the philosophy and study of disease causation in man. From the pragmatic and practical standpoint, we must agree that “the sum total of scientific evidence established beyond reasonable doubt that cigarette smoking is a causative factor in that this evidence is adequate for application in clinical preventive medicine and for the initiation of public health measure” [18]. 5. 5. Several behavioral aspects of the problem were mentioned.