[Establishment of a scoring system for predicting the positive rate of prostatic biopsy for prostate cancer].

ABSTRACT

OBJECTIVE: To identify the predictors of the positive results of transrectal ultrasound (TRUS)-guided biopsy for prostate cancer. METHODS: We performed univariate and multivariate logistic regression analyses on the relevant data on 385 male patients that underwent TRUS-guided biopsy for prostate cancer, including such potential predictors as age, body mass index (BMI), symptoms, results of digital rectal examination (DRE), tPSA, fPSA, free/total PSA ratio (f/tPSA), prostate volume (PV), and PSA density (PSAD) for identification of the risk factors related to the positive rate of biopsy. Then we constructed a scoring system as a tool for predicting prostate cancer in repeat biopsies and determined the sensitivity of the system by calculating the false positive rate using the receiver operating characteristic curve. RESULTS: Among the 385 patients, 139 (36.1%) were diagnosed with prostate cancer. On multivariate analysis, age (P < 0.01), DRE (P < 0.01), tPSA (P < 0.01), fPSA (P < 0.01), f/tPSA (P < 0.01), PV (P < 0.01), and PSAD (P < 0.01) were all significant predictors of prostate cancer. Multivariate logistic regression analysis showed age, tPSA, f/tPSA, PV, and PSAD to be independent predictors, with ORs and 95% CIs of 1.07 (1.05-1.16), 1.05 (1.02-1.15), 0.97 (0.86-0.99), 0.98 (0.87-0.96), and 1.79 (1.48-2.06), respectively. Moreover, patients with the risk score of 3-5 had a significantly higher rate of prostate cancer than those with 0-2 (64% vs 11%, P < 0.001). CONCLUSION: The scoring system on the key predictors of prostate cancer can help urologists to identify the men in need of prostatic biopsy.