Carcinogenic risk assessment: some points of interest for a discussion

This paper is aimed at providing some elements of discussion about points that emerge about the meaning of risk assessment procedures. The considerations that will be developed mainly pertain to four topics. First, the feasibility of objectively checking the validity of risk assessment results on the basis of epidemiological data, particularly for very low exposures. Second, the influence of uncertainty factors and the resulting variations in risk estimates. Third, the influence of individual susceptibility factors, easily entailing differences in risk in the order of three levels of magnitude. These differences, as a consequence of genetic factors, are often in the range of three orders of negritude and are more evident for low classes of exposure. In the general population, DNA repair related susceptibility should also be considered. Fourth, the mathematical model of the risk assessment procedure may itself influence the results. The default approach adopted by the US EPA is commented.