Introduction: PSA, the standard screening test for prostate cancer (CaP), has low sensitivity/specificity. Serum PSA can be elevated in benign conditions and in men with PSA<2.5 ng/mL, up to15% may have CaP. The PCA3 test is a new diagnostic tool that is increasingly used in clinical practice. Its feasibility and performance has not been evaluated in a true screening population. Methods: Our study evaluated the feasibility of collecting and processing a large volume of urine samples for PCA3 testing in a reliable and standardized manner using the community-based Prostate Cancer Awareness Week (PCAW) screening population at the University of Colorado Denver over a three year period (2006-08). PCA3 Scores (PCA3/PSA mRNA x10-3) were determined using transcription mediated amplification (Gen-Probe, Inc) at Avero Diagnostics. Results: A varied group of clinicians, including residents and NPs, received instructions on the extended DRE required to release prostate cells collected in the first catch urine. Samples were processed within 1-4 hours and frozen at -80°C. PCA3 results were generated from 349, 311, and 209 men participating in PCAW 2006, 2007, 2008, respectively (some results pending for 2008). In 2006, the informative rate for the PCA3 test was 98.6%, a rate similar to studies in controlled clinical settings. In 2007/2008, the rates were 96.9 and 99.5%. The participants were 71%, 73%, and 78% Caucasian (C) for each year, 17%, 18%, and 13% African American (AA), and 9%, 7%, and 7% Hispanic (H). For each of the years, C men tended to be older (mean range 64-66) than either AA (57-59) or H (58-59) men. The positive rate for PCA3 (\#8805;35) for each year was 25%, 25%, 26% for C men, 42%, 35%, 22% for AA men, and 16%, 17%, 18% for H men. The proportions for both PCA3+/PSA+ tests (\#8805;2.5 ng/ml) were lower in H men (0-6% in 3 years) compared to C (9-11%) and AA (4-12%). The proportions of PCA3+/ PSA- tests were higher in AA men (18-30%) compared to C (15-16%) and H (10-18%). Rates of PCA3-/PSA+ tests were similar in all racial groups (9-16%). In a separate screening study (2008 African American Men\#8217;s Health Summit) targeting AA men specifically, the PCA3 test (n=276) was informative in 98.6%. Similar observations of a higher proportion of men with PCA3+/PSA- results were noted: 4% PCA3+/PSA+, 15% PCA3+/PSA-, 6% PCA3-/PSA+. Conclusions: The PCA3 assay is acceptable to men and can be performed in a busy screening setting. The excellent informative rate shows the robustness of this test. Because AA men are at highest risk for CaP and tend to have their disease diagnosed at a higher stage and grade compared to other racial groups, the difference seen in the proportion of AA men PSA- but PCA3+ may help improve early detection in AA men.

Citation Information: In: Proc Am Assoc Cancer Res; 2009 Apr 18-22; Denver, CO. Philadelphia (PA): AACR; 2009. Abstract nr 1584.

100th AACR Annual Meeting-- Apr 18-22, 2009; Denver, CO

American Association for Cancer Research
2009