Statistical Analysis of Tumors Observed in Both Incidental and Fatal Contexts

[Charle]

How to use proc multtest to achieve the following requirements: When a tumor is fatal for some animals and is incidental for other animals in the experiment, data for the incidental and fatal tumors should be analyzed separately by the prevalence and the death rate methods. Results from the different methods can then be combined to yield an overall result. The combined overall result can be obtained simply by adding together either the separate observed frequencies, the expected frequencies, and the variances, or the separate T statistics and their variances. Thanks.

[StatDave]

You seem to be describing the Peto mortality-prevalence test that I assume you have seen since you specifically mention PROC MULTTEST which offers this test. See the example of using this test in the Examples section of the MULTTEST documentation.

[Charle]

Yes, thank you very much for your response. Analyzing incidental tumors and fatal tumors separately is no longer an issue. However, relevant statistical analysis guidelines for carcinogenicity studies stipulate that tumors falling into both the incidental and fatal categories must be analyzed separately as incidental cases and fatal cases. The results of these two analyses should then be combined to derive a single p-value. After reviewing extensive literature, I remain unclear on how to perform this combined p-value calculation. I kindly request your guidance on implementing this p-value computation.
The relevant guideline is titled: FDA (2001) Guidance for Industry Statistical Aspects of the Design,
Analysis, and Interpretation of Chronic
Rodent Carcinogenicity Studies of
Pharmaceuticals