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Detailed Analysis of Contamination and Compliance in Prostate PLCO

Principal Investigator
Name
Paul Pinsky
Institution
NCI, DCP, EDRG
Email
About this CDAS Project
Study
PLCO (Learn more about this study)
Project ID
2009-0076
Initial CDAS Request Approval
Apr 23, 2009
Title
Detailed Analysis of Contamination and Compliance in Prostate PLCO
Summary
In a trial of screening, use of the screening modalities in the control arm is known broadly as contamination. Knowledge of the type and extent of contamination is critical in being able to interpret trial outcome results. Recently, preliminary mortality outcome results were published for the prostate site. These results included a brief description of the contamination in the control arm. We propose to examine the contamination in more detail, using descriptive analyses as well as modeling.
Aims

Specific Aim I. Descriptive Analyses. We will examine the following: Contamination by time interval and reason (PSA, DRE, either). Contamination by baseline screening hx, age (other covariates?). Actual Tests in screened arm (i.e., compliant but no screen due to early protocol). Speciifc Aim II. Modeling Survey Data. We will use a model to translate survey results to an actual frequency distribution of tests (allows for direct comparison with screened arm and for further modeling down the road). Specific Aim III. Alternative measures of compliance. The practical effect of compliance and contamination will be felt in terms of earlier and more frequent diagnoses of cancer. Therefore, relative cancer incidence in each arm can be used to assess effective contamination. Specifically, we propose to estimate expected PCa incidence in the absence of screening using SEER rates from the pre-PSA era. Then we calculate the "effective" contamination over compliance ratio by taking ratio of excess cases over expected in the control arm versus screened arm

Collaborators

Tony Miller (University of Toronto)
Richard Fagerstrom (DCP, NCI)
Barnett Kramer (Office of Disease Prevention)
Phil Prorok (DCP, NCI)
Douglas Reding (Marshfield Clinic Researh Foundation)
Timothy Church (University of Minnesota)

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