Age, prostate volume, prostate-specific antigen and prostate-specific antigen density as predictor factors in results of transrectal ultrasonography-guided prostate biopsy

Abstract

Background: To identify the predictor factors, such as prostate-specific antigen (PSA), age, prostate volume (PV), and PSA density (PSAD) as indications to perform transrectal ultrasonography (TRUS)-guided prostate biopsy in reducing unnecessary biopsies and improving detection rate. Methods: A total of 1232 samples were obtained from the medical records of patients underwent prostate biopsy from January 2008 to December 2013 in Cipto Mangunkusumo Hospital Jakarta. Pre-biopsy data including age, PSA, prostate volume, and PSAD were obtained. The Mann-Whitney U-test and unpaired t-test were conducted on the quantitative variables; a chi-square test was used for qualitative variables. This study also conducted receiver operating characteristic (ROC) curve analysis to determine the cut-off point and the optimum specificity and sensitivity for each variable. Results: Among 1232 patients, 33.5% had a positive biopsy result. The median age and PSA (68 years and 57.45 ng/ml) in the positive biopsy group was higher than in the negative group (65 years and 11.69 ng/ml), p <0.001. PSAD in patients with PSA 4-10 ng/ml, 10-20 ng/ml, and 20 ng/ml (0.20, 0.35, 2.05) in positive group was higher than negative group (0.14, 0.24, 0.53), p <0.001. Those with a positive biopsy result had a lower median PV (42 ml (range, 13.8-208)) compared to those with negative biopsies (55.4 ml) (p <0.001). In ROC curve, PSAD had the highest sensitivity and specificity (81.4% and 82.0%) with a cut-off point of 0.43 ng/ml/ml (p <0.001). Conclusion: The incidence of PCa increased with higher PSA level, older age and lower PV. Utilization of PSAD 0.17 ng/ml/ml as a cut-off point in patients with PSA level between 4-10 ng/ml is recommended to improve PCa detection in Indonesian men.