BIOSTATISTICAL ISSUES IN THE DESIGN AND ANALYSIS OF ANIMAL CARCINOGENICITY EXPERIMENTS

Two-year animal carcinogenicity experiments are used to evaluate the p otential carcinogenicity from exposure to chemicals. The choice of exp osure levels, the allocation of animals to doses, the length of exposu re, and the choice of interim sacrifice times all affect the power of statistical tests for carcinogenic effects and the variance of interpo lated estimates of carcinogenic risk. In this paper, one aspect of thi s problems is considered: the ability of tumor incidence data to provi de information on carcinogenic mechanism and the optimal choice of des ign parameters with which to achieve this purpose. The direct applicat ion of biochemical data to the estimation of carcinogenic risk is also discussed in detail.