• Identification of individuals at particular risk looks at epidemiological studies and historical data to determine who in the general population may be at greater risk of developing certain types of cancer. This particular area of investigation has taken an important step forward in recent years since the advent of genetic testing. Investigations may involve the examination of particular risk factors, including lifestyle (tobacco use, alcohol consumption, obesity, lack of physical activity) or genetic predisposition.
• Developing ways to cure or control clinical disease is usually achieved by improving the prognosis for patients through the use of drugs, chemotherapeutic agents, radiation therapy, and/or surgical intervention.
Laboratory rodents, usually mice and rats, have assisted scientists in the field of cancer research and it is clear that they will continue to do so. They are used as experimental models in cancer research studies only where there is a justified need and only if absolutely necessary. The Institute of Cancer Research does not use animals for research if nonanimal alternatives are available, and endeavors to set humane endpoints for all research involving laboratory animals.
Because we need to use live animals in some research programs, it is essential that these living creatures be afforded the best care at all times. Staff tasked with caring for animals in the laboratory are continually striving to improve and enhance animal husbandry and welfare. An important part of this process is the use of humane endpoints in our animal experiments.
[According to] the OECD, a humane endpoint can be defined as “the earliest indicator in an animal experiment of severe pain, severe distress, suffering, or impending death.” Investigators make use of different humane endpoints depending on the tumor model being studied in any particular animal, and try wherever possible to determine accurate, predictive, and reproducible humane endpoints.
Humane endpoints should be a consideration for all experiments involving animals, but are essential in situations that may involve suffering or death (e.g., acute toxicology, infection, cancer, or inflammatory disease). They are just one manifestation in the process of refinement of animal experiments. Humane endpoints are best used with prospective planning for their use, not ad hoc to address specific welfare concerns as they might arise.
There are several considerations in arriving at the objective assessment of pain and suffering and translating this into the appropriate endpoint in a given experiment. An important point is the requirement to continually improve our skills at observing the animals and assigning some objective values to the observations we make (usually these are based on animal behavior and physiology). We also need to know, in any given study, which observations are the most significant indicators of animal pain and suffering, and have scientific acceptance of these measurements; otherwise they become invalid and unworkable. It follows, therefore, that validation and monitoring of other study parameters are required to ensure robust predictability of the endpoint and minimal interference with the scientific objectives.