title: A note on the role of background tumor incidence in risk assessment for carcinogens.
abstract: The extrapolation of animal bioassay data to humans for the purpose of estimating risk from food additives, drugs, pesticides, etc. is still the primary approach to carcinogenic risk assessment. When the extrapolation is based on tumor data with high background incidence (e.g., hepatocellular tumors in rodents), its direct relevance to the human situation is sometimes questioned. This paper suggests a method for adjusting the acceptable excess risk level for humans according to the background incidence of the tumor type used for extrapolating from animals to humans. Application of the suggested "fixed relative risk" extrapolation method in setting acceptable low-risk exposure levels for humans is illustrated for methylene chloride.
authors.affiliation: Food and Drug Administration, National Center for Toxicological Research, Jefferson, Arkansas 72079.
authors.forename: R L
authors.initials: RL
authors.lastname: Kodell
authors.forename: J J
authors.initials: JJ
authors.lastname: Chen
authors.forename: D W
authors.initials: DW
authors.lastname: Gaylor
mesh_terms: D002273:Carcinogens / Q000633:toxicity*; D006801:Humans; D008752:Methylene Chloride / Q000633:toxicity; D009369:Neoplasms / Q000453:epidemiology*; D012306:Risk; D013223:Statistics as Topic; D014481:United States; D014484:United States Environmental Protection Agency
chemical_list: D002273:Carcinogens; D008752:Methylene Chloride