IMPLEMENTATION OF EPA REVISED CANCER ASSESSMENT GUIDELINES - INCORPORATION OF MECHANISTIC AND PHARMACOKINETIC DATA

A workshop entitled ''Implementation of EPA Revised Cancer Assessment Guidelines: Incorporation of Mechanistic and Pharmacokinetic Data'' wa s held in Anaheim, California, in 1996 at the 35th Annual Meeting of t he Society of Toxicology (SOT), This workshop was jointly sponsored by the Carcinogenesis, Risk; Assessment, and Veterinary Specialty Sectio ns of the SOT, The thrust of the workshop was to discuss the scientifi c basis for the revisions to the EPA Guidelines for cancer assessment and EPA's plans for their implementation, This is the first revision t o the original EPA guidelines which have been in use by EPA since 1986 . The principal revisions are intended to provide a framework for an i ncreased ability to incorporate biological data into the risk assessme nt process. Two cases were presented, for chloroform and trichloroethy lene, that demonstrated the use of the revised guidelines for specific cancer risk assessments. Using these new guidelines, nonlinear margin of exposure analyses were proposed for these chemicals instead of the linearized multistage model previously used by the EPA as the default method. The workshop participants generally applauded the planned rev isions to the EPA guidelines, For the most part, they considered that the revised guidelines represented a positive step which should allow for and encourage the use of biological information in the conduct of cancer risk assessments. Several participants cautioned however that t he major problem with cancer risk assessments would continue to be the inadequacy of available data on which to conduct more scientific risk assessments. (C) 1997 Society of Toxicology.