Graduation Year

2006

Document Type

Dissertation

Degree

Ph.D.

Degree Granting Department

Public Health

Major Professor

Thomas J. Mason, Ph.D.

Keywords

Prostate, Cancer, Screening, Biomarker, Biopsy

Abstract

In the U.S., the number of prostate biopsies increases annually. This is partly due to elevated prostate specific antigen (PSA) values identified during PC screening. This study's goal was improving prostate cancer (PC) detection through developing a clinical decision rule (CDR), based on an elevated PSA and laboratory biomarkers. This decision rule could be used after an elevated PSA, providing the patient and clinician information to consider prior to biopsy. This cross-sectional study evaluated men from the Tampa, Florida, James A. Haley (JH) VA (N=1,378), from January 1, 1998, through April 15, 2005. The study hypothesized that specific lab biomarkers among JH VA PC cases would differ significantly from JH VA patients without PC. The following biomarkers were related to PC: hemoglobin (HGB) (OR=1.42 95%CI 1.27, 1.59); red blood cell count (RBC) (OR=2.52 95%CI 1.67, 3.78); PSA (OR=1.04 95%CI 1.03, 1.05); and, creatinine (OR=1.55 95%CI 1.12, 2.15).

This study attempted to determine whether including specific biomarkers (that are related to systemic diseases associated with advancing PC) could improve PC prediction (versus PSA alone). Comparing all PC stages versus non-cancerous conditions, the Receiver Operator Characteristic (ROC) curve area under the curve (AUC) expanded (increasing the probability of correctly classifying PC): PSA (alone) 0.59 (95% CI 0.55, 0.61); CDR model 0.68 (95%CI 0.65, 0.71), and the positive predictive value (PPV) increased: PSA 44.7%; CDR model 61.8%. Comparing PC (stages B, C, D) vs. other, the ROC AUC increased: PSA (alone) 0.63 (95% CI 0.58, 0.66); CDR model 0.68 (95% CI 0.68, 0.75), and the PPV increased: 20.6% (PSA); CDR model 55.3%. These results suggest evaluating certain biomarkers might improve PC prediction prior to biopsy. Moreover, the biomarkers may be more helpful in detecting clinically relevant PC. Follow-up studies should begin with replicating the study on different U.S. VA data-sets involving multiple practices.

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