67th Annual Meeting Abstracts

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Relationship Between the PCA3 Molecular Urine Test and Prostate Biopsy Results in an Active Surveillance Program
*Jeffrey Tosoian, Stacy Loeb, *Anna Kettermann, *Patricia Landis, *Debra J. Elliot, Jonathan I Epstein, Alan W. Partin, H. Ballentine Carter, *Lori J. Sokoll
Johns Hopkins Medical Institutions, Baltimore, MD

Introduction: Prostate cancer gene 3 (PCA3) is a prostate-specific non-coding mRNA that is significantly over-expressed in prostate cancer tissue. Urinary PCA3 levels have been associated with prostate cancer grade and extent, suggesting a possible role in monitoring patients on surveillance. We assessed the relationship between PCA3 and prostate biopsy results among men in a surveillance program.
Materials & Methods: Urine specimens were obtained from 294 men with prostate cancer enrolled in the Johns Hopkins surveillance program. The follow-up protocol included semi-annual free and total PSA measurements and digital rectal examination, as well as an annual surveillance prostate biopsy. We examined the association between PCA3 results and progression on surveillance biopsy (defined as Gleason pattern 4 or 5, more than 2 positive biopsy cores, or greater than 50% involvement of any core with cancer).
Results: Patients with progression on biopsy had a similar mean PCA3 score to patients without progression (60.0 vs 50.8, p=0.131). ROC analysis suggested that PCA3 alone was unable to identify men with biopsy progression (AUC = 0.589, 95% CI = 0.496-0.683, p=0.076). After adjustment for age and date of diagnosis, PCA3 was not significantly associated with progression on biopsy (p=0.15).
Conclusions: In men with low-risk prostate cancer who were carefully selected for surveillance, PCA3 score was not significantly associated with biopsy progression in the short-term. Further analysis is necessary to assess the utility of PCA3 in combination with other biomarkers or in selected subsets of patients undergoing surveillance.

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