Department of Radiology, School of Medicine, Yeungnam University, Korea.
Published online: September 1, 2001.
ABSTRACT
PURPOSE: To establish the criteria which can safely reduce the number of unnecessary biopsies by comparing the transrectal ultrasonography(TRUS) findings, serum prostate-specific antigen(PSA), and prostate specific antigen density(PSAD) in the decision of criteria for the prostatic biopsy using TRUS. MATERIALS AND METHODS: Two hundred and twenty patients underwent TRUS-guided prostate biopsy due to elevated PSA and/or focal nodule on TRUS were included. Sixty five(27.5%) patients were confirmed as prostate cancer, and remained 155(70.5%) patients were reported as benign diseases including benign prostatic hyper-plasia. The sensitivity, specificity and accuracy of TRUS, PSA and PSAD were evaluated and the single criterion or the combination of the criteria which can safely reduce the unnecessary biopsies without missing prostatic cancer were investigated. RESULTS: The sensitivity, specificity and accuracy of TRUS, PSA(cut-off value, 4 ng/ml) and PSAD(cut-off level,0.2 ng/ml/cm3) were 78.5%/95.4%/95.4%, 27.8%/51.6%/64.5%, 42.7%/64.5%/73.6%, respectively. PSAD cut-offlevel 0.2 ng/ml/cm3was the most excellent single criterion for the decision of prostatic biopsy and the number of unnecessary biopsies was 100 cases. But 3 cases of prostatic cancer which the PSAD level was below 0.2ng/ml/cm3 were included and in all these 3 cases, a focal nodule was detected on TRUS. Therefore, we applied these two criteria at once and The biopsies of 30 cases(13.6%) are unnecessary. CONCLUSION: With the single criterion, we could not obtain the satisfactory result but by the combinations of criteria(TRUS and PSAD), 30(13.6%) cases are unnecessary biopsies ithout missing cancer. We think that the short term follow-up may be a substitute for the immediate biopsy when nodular lesion is suspicious on TRUS and serum PSAD level is below 0.2ng/ml/cm 3.