Comparisons of the diagnostic accuracy across prostate health index, prostate health index density, and percentage free prostate-specific antigen for clinically significant prostate cancer: a prospective diagnostic study

Background: As the novel serum biomarkers, it has not been clearly clarified that the diagnostic accuracy of prostate health index (PHI) and prostate health index density (PHID) are superior to that of percentage free prostate-specific antigen (%fPSA) in detection of clinically significant prostate cancer (csPCa), especially in the gray zone. Therefore, this study aimed to compare the diagnostic value of PHI, PHID, and %fPSA for csPCa in the patients with prostate-specific antigen (PSA) >4 ng/mL and those with PSA within 4-10 ng/mL.Methods: In this study, the serum samples and clinicopathological features were prospectively obtained from the patients who underwent prostate biopsy between September 2019 and December 2020. According to the inclusion criteria, the patients with total PSA (tPSA) >4 ng/mL, prostate magnetic resonance imaging or ultrasound clearly suggesting an occupying lesion were enrolled in this study. The patients with Gleason score >= 7 indicated csPCa. The receiver operating characteristic curves and the area under the curve (AUC) values were used to assess the diagnostic performance.Results: Among the 296 patients (mean age 67.5 years, median tPSA 7.94 ng/mL) included in this study, there were 54 in the csPCa group (mean age 70.4 years, median tPSA 11.0 ng/mL) and 242 in the non-csPCa group (mean age 66.8 years, median tPSA 7.67 ng/mL). Based on the PSA level, there were 198 patients with PSA within the gray zone, which included 40 patients in the csPCa group and 158 in the non-csPCa group. In all patients, the sensitivity of PHID for detecting csPCa was 96.30%, and the specificity was 33.06% with the cut-off value of 0.51. Moreover, both PHID and PHI did better in the diagnosis of csPCa (AUC: 0.880 and 0.867, respectively) compared with other PSA derivative markers. Similarly, in the patients with PSA level in the gray zone, the diagnostic accuracy of PHID and PHI in predicting csPCa (AUC: 0.788 and 0.777, respectively) were better than other PSA derivative markers. Conclusions: PHID presented the better diagnostic accuracy in predicting csPCa in patients with PSA in the gray zone than other PSA derivative markers, which could be a promising biomarker for making the biopsy strategy.