MP74-13 URINARY (U)PCA3 AS A TEST TO MONITOR PATIENTS FOR DISEASE RECLASSIFICATION ON ACTIVE SURVEILLANCE (AS)

Abstract

INTRODUCTION AND OBJECTIVES: AS is gaining acceptance as a management strategy for men with low-risk prostate cancer and/or limited life expectancy. PSA has been shown to be an unreliable marker for important pathological changes on surveillance biopsy, and the success of AS requires periodic prostate biopsy. In the elevated PSA population, conflicting evidence exists between uPCA3 levels and the volume and grade of prostate cancer. uPCA3 may be a useful adjunct to biopsy among AS patients but its utility remains to be determined. METHODS: From a prospective biopsy database, clinical information and follow-up data was obtained of patients on AS managed at Cleveland Clinic from 2005 and 2013. The study was restricted to AS patients who had undergone surveillance uPCA3 testing after diagnosis of prostate cancer and committing to AS. Using Cox regression analysis, the association of surveillance uPCA3 levels (as a continuous variable and using cut-point of 25) with Gleason up-grading (increase in Gleason Score), volume progression (>50% of positive cores), and treatment was performed. RESULTS: uPCA3 levels were available for 104 AS patients, of whom 75 patients had received a subsequent biopsy. Mean age was 65.2 7.9 years, with mean PSA 6.1 4.9 ng/mL and mean PCA3 value 50.1 40.6. At diagnosis, 88% of patients were Stage T1c and 88% were Gleason grade 6. A total of 12 patients (12%) in the cohort underwent treatment. Mean PCA3 levels were not significantly different between patients that experienced grade/volume progression (63.8 29) and those who did not (47.2 49, P1⁄40.2). Similarly, the proportion of patients with level >25 was not significantly different among those who did and did not experience progression (p1⁄4.10). A positive PCA3 test during the AS period was not associated with increased odds of undergoing treatment (OR 0.875, 95% confidence interval (CI) 0.24-3.1. Using Cox regression modeling, uPCA3 was not associated with biopsy progression (HR 1.01; 95% CI: 0.99-1.02; P 1⁄4 0.16) or treatment (HR 0.99; 95% CI: 0.98-1.01; P 1⁄4 0.9); similar results were observed when modeled as a categorical variable (P > 0.05 for both). CONCLUSIONS: Among men with favorable clinical features on AS, uPCA3 was not associated with important disease reclassification (by change in Gleason score or percentage of positive cores) or the receipt of deferred therapy. As such, uPCA3 can not be used in lieu of other surveillance tests such as prostate biopsy and/or MRI. Prospective studies based on large cohorts with mature follow-up are needed to properly assess the utility of uPCA3 in the AS population.