Tumor Control Index as a new tool to assess tumor growth in experimental animals

Measurement of tumor diameters, tumor volumes, or area under the curve has been traditionally used to quantitate and compare tumor growth curves in immune competent as well as immune-compromised mice and rats. Here, using tumor growth data froma large number ofmice challengedwith live tumor cells,we describe the use of a new composite parameter, Tumor Control Index (TCI) as an alternative method to do the same. This index, comprised of three distinct values, the Tumor Inhibition Score, Tumor Rejection Score, and Tumor Stability Score, provides a complete picture of nearly every aspect of tumor growth in large numbers of animals, can be deduced automatically from tumor diameter or volume data, and can be used to compare several groups of animals in different experiments. This automatically derivable index also corresponds neatly to the use of complete and partial responses and tumor stability data generated in human tumors, and can be used to assess the efficacy of interventions to be used in clinical studies.