Impact of Histopathological Prostate Inflammation on Urine-Based Prostate Cancer Prediction Using the Prostate Cancer Gene 3 Score

Introduction: The Prostate Cancer gene 3 (PCA3) urine test has gained importance in the diagnostic workup of prostate cancer (PC). Limited evidence suggests that PCA3 is not altered in the presence of inflammation. Objective: To assess the impact of histological inflammation on PCA3. Methods: PCA3 was evaluated in patients prior to prostate biopsy (n = 193) and to radical prostatectomy (n = 197). In patients without PC, inflammation was assessed and quantified by individual scores integrating grade and extent. Uni- and multivariate analyses were performed to assess the impact of inflammation grade on PCA3. Results: The PCA3 scores prior to prostatectomy were lower (median 45) than those before positive biopsy (57; p = 0.008). Of 101 negative biopsies, 78% showed inflammation. The median PCA3 scores in the groups with no inflammation and with maximum grade 1 (n = 22), 2 (n = 38), and 3 (n = 19) inflammation were 45, 38, 27, and 25 (p = 0.016). The multivariate models revealed a decrease in PCA3 proportional to the grade and extent of inflammation (p < 0.04 each). Conclusions: The present data imply that the PCA3 score decreases in the presence of inflammation, which is relevant, for instance, to testing after a recently performed biopsy. In general, inflammation should be regarded as a factor putatively influencing PCA3 and other available and upcoming PC tests.