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. Copyright © 2009 John Wiley & Sons, Ltd.