Revisiting alternative approaches to the assessment of carcinogenic risk.

The rodent bioassay has been a mainstay of carcinogenic risk assessment for close to half a century; not that it has been without criticism in that time. As early as the 1990s, there were clearly established shortcomings with regard to relevance and extrapolation, but despite these concerns, this test continues relatively unchanged. As our understanding of the mechanisms of carcinogenesis and the availability of investigative techniques improve, there seems less reason than ever to persist with this exercise that provides little meaningful scientific data at great cost in terms of animal usage and pathologist time. This article highlights possible ways to gather and present data pertinent to carcinogenesis in man and suggests that it is the toxicological pathology community that should take the lead here in persuading regulators that there is great room for improvement in this particular aspect of regulatory pathology.