[Quantitative methods of cancer risk assessment in exposure to chemicals].
This is a methodology paper--it contains a review of different quantitative risk assessment methods and their comparison. There are two aspects of cancer risk modeling discussed here: 1. When there is one effective dose only. There were compared two models in this evaluation: one proposed by the Dutch Expert Committee on Occupational Standards and the other--a classical two-stage model. It was taken into account that in both models the animals were exposed for less than two years. An exposure period and a study period of animals were considered in the Dutch methodology. If we use as an exposure measure average lifespan dose estimated with different coefficients of exposure time in an experiment, we get two different dose-response models. And each of them will create different human risk models. There is no criterion that would let us assess which of them is better. 2. There are many models used in the BenchMark Dose (BMD) method. But there is no criterion that allows us to choose the best model objectively. In this paper a two-stage classical model and three BMD models (two-stage, Weibull and linear) were fit for particular data. Very small differences between all the models were noticed. The differences were insignificant because of uncertainties in the risk modeling. The possibility of choice of one model from a bigger set of models is the greatest benefit of this comparison. If the examined chemical is a genotoxic carcinogen, nothing more is needed than to estimate the threshold value.
Szymczak
Wiesław
W
Instytut Medycyny Pracy im. prof. I. Nofera, Lódź, Zakład Epidemiologii Srodowiskowej. swiesiek@yahoo.co.uk
D000465:Algorithms; D000818:Animals; D019985:Benchmarking; D002273:Carcinogens / Q000633:toxicity*; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D004781:Environmental Exposure / Q000032:analysis*; D016014:Linear Models; D016012:Poisson Distribution; D018570:Risk Assessment / Q000379:methods; D014050:Toluene / Q000031:analogs & derivatives / Q000633:toxicity; D018675:Toxicity Tests / Q000379:methods*
D002273:Carcinogens; D014050:Toluene; C029955:2-nitrotoluene