DIRECTED AND RANDOM BIOPSIES OF THE PROSTATE - INDICATIONS BASED ON COMBINED RESULTS OF TRANSRECTAL SONOGRAPHY AND PROSTATE-SPECIFIC ANTIGEN DENSITY DETERMINATIONS

OBJECTIVE. We studied the usefulness of transrectal sonography, prosta te-specific antigen levels, and prostate-specific antigen density as i ndications for directed and random biopsies of the prostate in patient s with possible prostatic cancer. MATERIALS AND METHODS. A total of 14 1 patients with increased levels of prostate-specific antigen or abnor mal findings on digital rectal examination had transrectal sonography of the prostate and determination of prostate-specific antigen density . Through sonographic visualization, all patients had biopsies of poss ible cancerous lesions and random biopsies of regions of the prostate that appeared normal. Histologic results were correlated with sonograp hic findings and determinations of prostate-specific antigen levels an d prostate-specific antigen density. RESULTS. Adenocarcinoma was detec ted in 40 (28%) of the 141 patients. Transrectal sonography showed an abnormality that was determined by directed biopsy to be a carcinoma i n 27 (68%) of the 40 patients. Transrectal sonography showed no carcin oma in 13 patients (32%) for whom random biopsy revealed a tumor. The sensitivity of sonography was 68%, and the specificity was 49%. The co mbination of sonographic findings suggestive of cancer and increased p rostate-specific antigen density had a sensitivity of 75% acid a speci ficity of 75%; we calculated a sensitivity of 72% and a specificity of 56% for the combination of sonographic findings suggestive of tumor a nd increased levels of prostate-specific antigen. Thirty-nine (97%) of 40 patients with cancer had either sonographic findings suggestive of tumor or increased prostate-specific antigen density, and one (3%) ha d no evidence of tumor on sonography and a normal prostate-specific an tigen density. CONCLUSION. Directed and random sonographic biopsies of the prostate are indicated in patients with sonographic findings sugg estive of tumor and increased prostate-specific antigen density and in patients with abnormal sonographic findings and normal prostate-speci fic antigen density. Random biopsies are indicated in patients with no rmal sonographic findings and increased prostate-specific antigen dens ity. In our series, random biopsies were not indicated in 25 of 26 pat ients with normal sonographic findings and normal prostate-specific an tigen density. Further research on the need for random biopsies when t here are no sonographic abnormalities and when prostate-specific antig en densities are not elevated is warranted.