Percent free prostate-specific antigen is effective to predict prostate biopsy outcome in Chinese men with prostate-specific antigen between 10.1 and 20.0 ng ml(-1).

Percent free prostatic-specific antigen (%fPSA) has been introduced as a tool to avoid unnecessary biopsies in patients with a serum PSA level of 4.0-10.0 ng ml-1 , however, it remains controversial whether %fPSA is effective in PSA range of 10.1-20.0 ng ml-1 in both Chinese and Western population. In this study, the diagnostic performance of %fPSA and serum PSA in predicting prostate cancer (PCa) and high-grade PCa (HGPCa) was analyzed in a multi-center biopsy cohort of 5915 consecutive Chinese patients who underwent prostate biopsy in 22 hospitals across China from January 1, 2010 to December 31, 2013. The indication for biopsy was PSA>4.0 ng ml-1 or/and suspicious digital rectal examination. Total and free serum PSA determinations were performed by three types of electrochemiluminescence immunoassays with recalibration to the World Health Organization standards. The diagnostics accuracy of PSA, %fPSA and %fPSA in combination with PSA (%fPSA + PSA) was determined by the area under the receivers operating characteristic curve (AUC). %fPSA was more effective than PSA in men aged ≥60 years old. The AUC was 0.584 and 0.635 in men aged ≥60 years old with a PSA of 4.0-10.0 ng ml-1 and 10.1-20.0 ng ml-1 , respectively. The AUC of %fPSA was superior to that of PSA in predicting HGPCa in patients ≥60 years old in these two PSA range. Our results indicated that %fPSA is both statistically effective and clinical applicable to predict prostate biopsy outcome in Chinese patients aged ≥60 years old with a PSA of 4.0-10.0 ng ml-1 and 10.1-20.0 ng ml-1 .