Predictive value of the international prostate symptom score for positive prostate needle biopsy in the low-intermediate prostate-specific antigen range

PURPOSE: Serum prostate-specific antigen (PSA) has a restricted predictive value for prostate cancer in the low-intermediate PSA range (2.5-10 ng/ml). Our aim was to determine the predictive value of the International Prostate Symptom Score (IPSS) for positive prostate needle biopsy (PNB) in patients who underwent transrectal ultrasound (TRUS)-guided prostate biopsy with a low-intermediate PSA level. PATIENTS AND METHODS: Between 2001 and 2004, the data of 389 consecutive patients applying for any urologic complaint to our department and who underwent TRUS-guided prostate biopsy due to an elevated serum PSA and/or abnormal digital rectal examination (DRE) were retrospectively analyzed. A total of 158 eligible patients with a low-intermediate PSA level were included in the study. The patient's age, PSA, free PSA, free/total PSA, prostate volume, PSA density (PSAD), pre-biopsy IPSS were compared in the positive and negative biopsy groups. RESULTS: Fifty-eight of 158 patients (37%) who underwent TRUS-guided prostate biopsy had positive PNBs. Forty-eight patients (30%) had abnormal DREs. In the positive PNB group, the mean age was older and PSAD was higher, but the means of the prostate volumes and total IPSS were lower (p<0.05). Multivariate analysis demonstrated that age and IPSS were independent predictors of a positive PNB (p<0.05). The odds ratio of mild IPSS for positive PNB controlled for age was 3.0 (95% CI 1.5-6.7). Receiver-operating characteristics analysis revealed a mild IPSS (AUC=0.640) and was a considerable predictor for positive PNB as well as PSAD (AUC=0.648). The sensitivity and specificity of IPSS with a cutoff value of 7.5 points were 31 and 87% for prediction of prostate cancer detection. CONCLUSION: In the low-intermediate PSA range, mild IPSS may be a predictive factor for positive PNB with a similar specificity of PSAD.