Animal number versus maximum tumour volume: an example of reduction and refinement trade-off in the 3Rs.

Abstract

In this correspondence, we discuss the trade-off that exists between the reduction and refinement principles of the 3Rs in tumour growth studies. We show, by means of a power analysis considering a realistic setting, that an increase in the maximum tolerated tumour volume leads to a decrease in animal number. We therefore argue that the reduction and refinement principles must be assessed as a function of one another for the determination of appropriate humane and scientific endpoints during ethical review processes.