Comparison among different precursor prostate-specific antigen isoform derivatives on prostate cancer prediction in patients with serum prostate-specific antigen bellow 10 ng/ml

Introduction/Objective The precursor prostate-specific antigen (proPSA) especially its isoform p2PSA is useful in the detection of prostate cancer (PCa). However, the prediction value of different p2PSA deriva-tives remains unclear. The aim of the study was to compare the performance of the p2PSA, percentage of p2PSA to free PSA (%p2PSA), prostate health index (Phi), and one prostate dimension-adjusted index, p2PSA density (p2PSAD), with each other for PCa prediction in patients with serum PSA 10 ng/ml or less. Methods This prospective study included patients who had undergone ultrasound-guided prostate biopsies and p2PSA testing. The data about patients' clinicopathological characteristics were collected and %p2PSA, p2PSAD and Phi were calculated. Different aspect of predictive performance was assessed using the area under the receiver operating characteristic curve (AUC), the specificities at set sensitivities, and clinical utility using decision curve analyses (DCA). Results PCa was diagnosed in 23 (32.4%) out of 71 patients. Results of multivariate analysis showed that only the Phi and digital rectal examination were independent predictors of PCa.The AUC of p2PSA, %p2PSA, p2PSAD and Phi were 76.2%, 81.5%, 88.7%, 89.6%, respectively. At pre-specified sensitivity of 90% and 95%, Phi demonstrated a greater specificity than the other p2PSA derivatives. Phi and p2PSAD lead to the higher net benefit in DCA. Conclusion Compared with other p2PSA derivatives Phi is the most useful parameter for selection of the patients that do not need to be undergone to biopsy and thereby avoiding unnecessary procedures.