Accuracy of the Prostate Health Index Versus the Urinary Prostate Cancer Antigen 3 Score to Predict Overall and Significant Prostate Cancer at Initial Biopsy

BACKGROUNDIt remains unclear whether the Prostate Health Index (PHI) or the urinary Prostate-Cancer Antigen 3 (PCA-3) score is more accurate at screening for prostate cancer (PCa). The aim of this study was to prospectively compare the accuracy of PHI and PCA-3 scores to predict overall and significant PCa in men undergoing an initial prostate biopsy. METHODSDouble-blind assessments of PHI and PCA-3 were conducted by referent physicians in 138 patients who subsequently underwent trans-rectal ultrasound-guided prostate biopsy according to a 12-core scheme. Predictive accuracies of PHI and PCA-3 were assessed using AUC and compared according to the DeLong method. Diagnostic performances with usual cut-off values for positivity (i.e., PHI >40 and PCA-3 >35) were calculated, and odds ratios associated with predicting PCa overall and significant PCa as defined by pathological updated Epstein criteria (i.e., Gleason score 7, more than three positive cores, or >50% cancer involvement in any core) were estimated using logistic regression. RESULTSPrevalences of overall and significant PCa were 44.9% and 28.3%, respectively. PCA-3 (AUC=0.71) was the most accurate predictor of PCa overall, and significantly outperformed PHI (AUC=0.65; P=0.03). However, PHI (AUC=0.80) remained the most accurate predictor when screening exclusively for significant PCa and significantly outperformed PCA-3 (AUC=0.55; P=0.03). Furthermore, PCA-3 >35 had the best accuracy, and positive or negative predictive values when screening for PCa overall whereas these diagnostic performances were greater for PHI >40 when exclusively screening for significant PCa. PHI>40 combined with PCA-3>35 was more specific in both cases. In multivariate analyses, PCA-3 >35 (OR=5.68; 95%CI=[2.21-14.59]; P<0.001) was significantly correlated with the presence of PCa overall, but PHI >40 (OR=9.60; 95%CI=[1.72-91.32]; P=0.001) was the only independent predictor for detecting significant PCa. CONCLUSIONSAlthough PCA-3 score is the best predictor for PCa overall at initial biopsy, our findings strongly indicate that PHI should be used for population-based screening to avoid over-diagnosis of indolent tumors that are unlikely to cause death. Prostate 75:103-111, 2015. (c) 2014 Wiley Periodicals, Inc.