Under project licence authorities issued under the Animals (Scientific Procedures) Act 1986, a two year carcinogenicity study would involve a series of regulated procedures forming a single protocol. The regulated procedures in the series would entail the administration of the test substance by one of a number of routes, for example, orally, by injection, through inhalation, or applied to the skin. Each route would be expected to produce only mild, momentary discomfort. Occasional blood samples may also be taken in some cases. The licence authorities require that animals will be humanely killed before any tumours produced during the observation period cause serious adverse effects. Overall the protocol would be expected to be of mild or moderate severity.
The International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use (ICH) and the Organisation for Economic Co-operation and Development (OECD) publish International guidelines for the conduct of carcinogenicity studies for pharmaceuticals and chemicals, respectively, to which studies conducted in the United Kingdom are expected comply.