Percent free prostate-specific antigen does not improve the effectiveness of prostate cancer detection in Chinese men with a prostate-specific antigen of 2.5-20.0 ng/ml: a multicenter study.

The prostate-specific antigen (PSA) "gray zone" in Chinese men is likely higher than the traditional value (2.5-10.0 ng/ml) since the incidence of prostate cancer in Chinese men is relative low. The utility of percent free PSA in predicting prostate cancer is based on Western populations and may introduce sizable bias when applied to a Chinese cohort. We assessed the efficacy of percent free PSA in predicting prostate cancer in Chinese men with a PSA of 2.5-10.0 and 10.1-20.0 ng/ml. A total of 558 men with a PSA of 2.5-20.0 ng/ml who had undergone prostatic biopsy to detect prostate cancer from two Chinese centers were included. The rates of prostate cancer in different percent free PSA ranges were evaluated. Receiver operating characteristic curve (ROC) was used to evaluate and compare the efficiency of PSA and percent free PSA in the diagnosis of prostate cancer. The areas under ROC (AUCs) for percent free PSA for predicting prostate cancer were not higher than those for PSA, although prostate cancer detection rates increased with decreased percent free PSA in men with a PSA of 2.5-10.0, 10.1-20.0, and 2.5-20.0 ng/ml. Similarly, for men aged <70 and ≥ 70 years and with prostate volume <40 and ≥ 40 ml, AUCs showed percent free PSA was not better than PSA in predicting prostate cancer. By analyzing multicenter data, we first found that percent free PSA does not improve detection of prostate cancer in Chinese men with a PSA of 2.5-10.0 or 10.1-20.0 ng/ml.