[Exposure to tobacco tars and risk of lung cancer in smokers].

A formula to quantify the tar exposure of smokers is described, it uses informations of the life long smoking habits of the individual and offers some aspects to the prevention and early detection of lung cancer. The average tar exposure of male tumor patients is significantly higher than the tar exposure of controls. There is a significant difference between Kreyberg I tumors and controls but not between Kreyberg II tumors and controls. The average tar exposure of a female tumor patient is significantly higher than the average tar exposure of female controls, but significantly lower than the average tar exposure of a male patient. Tar exposure is of course related to lung cancer risk in a dose response relationship. To contribute to the question of thresholds of lung cancer risk one identifies tar exposures which might be helpful in the further discussion. The application of the formula for tar exposure could lead to a more precise definition of people at extreme risk. These should be screened first, also because of the excess morbidity caused by other tobacco-related diseases.