['To improve prostate cancer (PC) detection accuracy among patients with a prostate-specific antigen (PSA) above 4.0 ng/ml and asymptomatic prostate inflammation.', 'A total of 136 patients with PSA ranging from 4.0 to 50.0 ng/ml with asymptomatic prostatitis were included in the study cohort. All these patients underwent antibacterial therapy for 2 weeks followed by repeat PSA determination and transrectal ultrasound-guided needle prostate biopsy. The PSA, PSAD (PSA density), and f/t PSA (free/total PSA) before and after antibacterial therapy were compared using t-test. The receiver-operating characteristic (ROC) technique was used to evaluate the effectiveness of PSA, PSAD, f/t PSA, and their changes after antibacterial therapy (DeltaPSA, DeltaPSAD, and Deltaf/t PSA) on PC detection.', 'Among the 136 patients, 33 had PC and the other 103 histologically confirmed benign prostatic disease. After antibacterial therapy for 2 weeks, the PSA (mean +/- standard deviation) decreased from 14.0 +/- 7.8 ng/ml to 10.4 +/- 7.7 ng/ml (P < 0.01). The DeltaPSA, DeltaPSAD, and Deltaf/tPSA were -3.60 +/- 4.3 ng/ml, -0.1 +/- 0.1 ng/ml/ml, and -0.1 +/- 0.1 respectively. The areas under ROC curve were 0.29 for PSA, 0.64 for PSAD, and 0.50 for f/t PSA. The areas under ROC curve were 0.91 for DeltaPSA, 0.96 for DeltaPSAD, and 0.98 for Deltaf/t PSA. These values were increased significantly when compared with those for the PSA-related parameters before antibacterial therapy (P value, DeltaPSA, DeltaPSAD, and Deltaf/t PSA were <0.01).'] Does antibacterial therapy improve the effectiveness of prostate cancer detection using prostate-specific antigen in patients with asymptomatic prostatitis?