Interval approach to assessing antitumor activity for tumor xenograft studies.

In preclinical cancer drug screening tumor xenograft experiments, the tumor growth inhibition ratio (T/C) is commonly used to assess the antitumor activity of the agents. Unfortunately, this measurement can discard useful data and result in a high false-negative rate. Furthermore, the degree of antitumor activity based on the T/C ratio is assessed on the basis of an arbitrary cutoff point that does not reflect variations in different tumor lines. To overcome these drawbacks, we propose an adjusted area-under-the-curve (aAUC) ratio to quantify tumor growth inhibition. A nonparametric bootstrap t-interval of the aAUC ratio is also proposed for assessing the significance of the antitumor activity of the agents. The proposed method is then applied to a real tumor xenograft study. (c) 2009 John Wiley & Sons, Ltd.