Prostate health index vs percent free prostate-specific antigen for prostate cancer detection in men with "gray" prostate-specific antigen levels at first biopsy: systematic review and meta-analysis

The most promising approach to improve the specificity of prostate-specific antigen (PSA) test relies on the measurement of different molecular isoforms of PSA in serum. Currently, in men with a total PSA (tPSA) level between 2 and 10 ng/mL, measurement of %fPSA (free to total PSA ratio x100) is used as reflex testing to better distinguish between malignant and benign prostate disease. Recently, Beckman Coulter developed the prostate health index (PHI) and several studies suggested that this test may improve the diagnostic ability of %fPSA. We performed a meta-analysis to evaluate the usefulness of PHI compared with %fPSA in the detection of prostate cancer (PCa) at first biopsy in men with tPSA "gray" levels of 2-10 ng/mL. Data on sensitivity and specificity were extracted from 8 eligible studies. Only observational studies comparing the diagnostic ability of PHI and %fPSA in tPSA range of 2-10 ng/mL were included. A total of 8 studies involving 2969 patients with a tPSA range of 20 ng/mL undergoing first biopsy were included in this meta-analysis. Biopsy-confirmed PCa was detected in 1287 (43.3%) men. Selected studies determined both PHI and %fPSA as a reflex test. The areas under curve (AUCs) of PHI and %fPSA were 0.74 (95% confidence interval (CI), 0.70-0.77) and 0.63 (95% CI, 0.58-0.67), respectively. Meta-regression analysis confirmed the superiority of PHI which showed, compared with %fPSA, a relative diagnostic odds ratio of 2.81 (95% CI, 2.19-3.6; P < 0.0001). In conclusion, PHI instead of %fPSA as a reflex test in men with tPSA "gray" levels is a better predictor of positive first biopsy and can offer a reduction in unnecessary biopsies.