[Epidemiologic studies on the role of tobacco in various human cancers]

The totality of epidemiological research over the last 25 years in the field of the relationship between tobacco consumption and the chance of developing certain cancers has demonstrated beyond reasonable doubt that the use of tobacco is implicated in the genesis of a certain number of cancers of the respiratory tract and the upper air and food passages. The most important relationship concerns carcinoma of the bronchus, currently the most frequently encountered in men, for which the incidence risk is directly related to the use of cigarettes and which rises with the amount smoked and with inhaling. Other possible aetiological factors, particularly occupational exposure to chemical and radio active agents, whilst interesting are none the less marginal. The ramifications of epidemiologic and experimental researchs lead us to envisage a multifactorial aetiology in which tobacco is a constant element. Avoidance of exposure would play a major role in prevention.