Knight A, Bailey J, Balcombe J. Animal carcinogenicity studies: implications for the REACH system. Alternatives to Laboratory Animals 2006; 34 suppl 1:139-147. Download (119kb).

 

ABSTRACT
The 2001 European Commission proposal for the Registration, Evaluation and Authorisation of Chemicals (REACH) aims to improve public and environmental health by assessing the toxicity of, and restricting exposure to, potentially toxic chemicals. The greatest benefits are expected to accrue from decreased cancer incidences. Hence the accurate identification of chemical carcinogens must be a top priority for the REACH system. Due to a paucity of human clinical data, the identification of potential human carcinogens has conventionally relied on animal tests. However, our survey of the US Environmental Protection Agency’s (EPA’s) toxic chemicals database revealed that, for a majority of the chemicals of greatest public health concern (93/160, i.e. 58.1%), the EPA found animal carcinogenicity data to be inadequate to support classifications of probable human carcinogen or non-carcinogen. A wide variety of species were used, with rodents predominating; a wide variety of routes of administration were used; and a particularly wide variety of organ systems were affected. These factors raise serious biological obstacles that render accurate extrapolation to humans profoundly difficult. Furthermore, significantly different International Agency for Research on Cancer assessments of identical chemicals, indicate that the true human predictivity of animal carcinogenicity data is even poorer than is indicated by the EPA figures alone. Consequently, we propose the replacement of animal carcinogenicity bioassays with a tiered combination of non-animal assays, which can be expected to yield a weight-of-evidence characterisation of carcinogenic risk with superior human predictivity. Additional advantages include substantial savings of financial, human and animal resources, and potentially greater insights into mechanisms of carcinogenicity.

  

 

Veterinarian Andrew Knight BSc., BVMS, CertAW, MRCVS, is the Founder, Director and web designer of Animal Consultants International. He is an expert on humane alternatives to harmful animal use in education, animal experimentation, and vegetarian companion animal diets. An active animal advocate since 1995, he has extensive public speaking, media, research and writing experience.

 

Biologist Jonathan Balcombe, Ph.D. (Ethology), author of The Use of Animals in Higher Education, a forthcoming book on animal pleasure, and many scientific articles on humane education and animal behavior, promotes alternatives to animal use in research and education. Formerly an Associate Director with The Humane Society of the United States, he is currently a Research Consultant with the Physicians Committee for Responsible Medicine.