Standard Article

Tumor Incidence Experiments

  1. Gregg E. Dinse

Published Online: 15 JUL 2005

DOI: 10.1002/0470011815.b2a07055

Encyclopedia of Biostatistics

Encyclopedia of Biostatistics

How to Cite

Dinse, G. E. 2005. Tumor Incidence Experiments. Encyclopedia of Biostatistics. 8.

Author Information

  1. National Institute of Environmental Health Sciences, Research Triangle Park, NC, USA

Publication History

  1. Published Online: 15 JUL 2005


This article describes a variety of methods for analyzing data from animal tumorigenesis experiments. The primary endpoint of interest is the tumor incidence rate. Both the estimation of tumor incidence rates and the comparison of these rates across treatment groups are discussed. Analyses are complicated by the fact that all onset times are censored when tumors are occult, censoring is informative unless tumors are completely nonlethal, and biases arise if proper adjustment is not made for survival differences across groups. Existing methods address such concerns by assuming a particular level of tumor lethality, assigning individual causes of death, requiring some animals to be sacrificed, specifying parametric models, or imposing functional restrictions. This article describes each of these approaches and summarizes the associated advantages and disadvantages.


  • cause of death;
  • competing risks;
  • differential mortality;
  • fatal tumors;
  • incidental tumors;
  • survival/sacrifice study;
  • tumor lethality;
  • tumor onset