An Alternative to Rodent Studies for Assessing Agrichemical Cancer Risk

Scientists have long relied on rodent studies to assess human cancer risks from various chemicals, but rodent studies are resource intensive, use hundreds of animals, and in the end, may not be relevant to humans.

Exponent's Elaine Freeman and Kyle Wilson present an alternative to rodent cancer studies in their recent publication on the use of integrated approaches for testing and assessment (IATA). The paper, co-authored with colleagues from Syngenta and PSCI/PETA and published by the Organisation for Economic Co-operation and Development, outlines a framework that can be used to assess the chronic toxicity and carcinogenicity of agrichemicals. 

The IATA for chronic toxicity and carcinogenicity of agrichemicals aims to replace traditional rodent bioassays with a weight-of-evidence (WoE) approach. The key components include retrospective evaluations of use patterns, exposure scenarios, physicochemical properties, metabolism, toxicokinetics, and toxicological data. The IATA emphasizes the importance of mechanistic data and the reliability and consistency of toxicological responses.

The paper also includes two case studies for the chemicals saflufenacil and spiropidion that illustrate the application of the WoE-based approach to estimate a point of departure (POD) for chronic risk assessment without performing lifetime rodent bioassays. The publication encourages the development of additional case studies and further discussion to explore the IATA's applicability beyond agrichemicals, potentially supporting safety evaluations under various regulatory regimes.

From the publication: "The framework and associated example case studies illustrate a WoE-based approach to identify sufficiency of data to estimate a point of departure (POD) that is human health protective against chronic risk — without performing the lifetime rodent bioassays."