[Cancerogenic activity of antimitotic agents in animals]

In past years, health authorities have exempted anti-neoplastic agents from undergoing carcinogenesis tests. However, in view of increasing knowledge of this therapeutic family and of patients' increased life expectancy, toxicologists are having to reconsider the problem from both ethical and scientific points of view. Analysis of data has established a correlation between mutagenic activity of these molecules, carcinogenic activity in the animal and carcinogenic activity in man. For this reason, studies in laboratory animals are of interest at the present time. Assessment of the carcinogenic activity of anti-neoplastic agents in animals must take into account the chemical structure of the drug. The experiments to be carried out are: either in vitro, short term tests aimed to detect genotoxic drugs by mutagenesis tests, or limited in vivo tests, in order to determine the promoting or initiating character of these drugs. However, the obtention of negative results with the latter tests does not exclude the necessity of long term tests. Whatever the results obtained during these experiments, the decision to stop or to continue the development of an anti-neoplastic agent does not belong exclusively to the toxicologist, who can assess the risk, but not the potential benefice.