Use of Short-Term Test Data in Risk Analysis of Chemical Carcinogens

Abstract

As the other chapters of this volume will attest, the area of risk analysis of chemical carcinogens is a new and emerging field of science that is intermingled with economic, societal, and political values. The concept that short-term tests, which will be defined and described later in this chapter, can affect the final outcome of a risk analysis is both recent and controversial. While we have not conducted a scientifically valid survey, we have done extensive sampling among highly credible and well regarded scientists whose pro fessional activities impinge on the boundaries of the area we call risk analysis. The question asked of them was, what is the value of short-term test data in risk assessment? Approximately 10% opined that risk analysis is valueless; the remainder were evenly divided between those believing that short-term tests have no value at all to risk analysis and those who view short-term tests as holding some promise and utility for risk analysis. Among the latter group, there were those who believed that short-term tests were useful for making qualitative judgments only and they should not have an impact on quantitative risk analysis. Others felt that the main value of short-term tests in risk assessment would be for classification purposes, that is, to determine whether a substance is a genotoxic carcinogen, thus prompting the use of a conservative nonthreshold linearized extrapolation model, as opposed to a risk extrapolation approach which envisions a threshold. Finally, there were others who said they believed that short-term test data could be valuable both for qualitative and quantitative assessments, but that it is too early and scientific experience is too limited to provide general guidance on the subject. They felt, however, that there have been and that there would be specific situations where short-term tests would prove invaluable in determining a final outcome.