Prostate cancer tumor location as predicted by digital rectal examination transferred to ultrasound and ultrasound-guided prostate needle biopsy

Abstract

The advent of transrectal ultrasound (TRUS) and the Biopty instrument (Bard Urologic) has revolutionized prostate biopsy (PNB). Theoretically the systematic multiple biopsy approach offers the advantage of less sampling error with respect to presence of carcinoma, grade of carcinoma and sites of tumor within the gland. These parameters may be important in selecting the therapeutic approach and, if radical prostatectomy is contemplated, in modifying the operation as indicated based on tumor location. In the present investigation, we received specimens obtained from 100 men with clinically localized prostatic carcinoma who had previously undergone ultrasound-guided systematic random biopsy (TRUSPNB) along with TRUS and digital rectal exam (DRE). Among the 372 sectors with carcinoma identified in the 100 radical prostatectomy specimens, significant underrepresentation by TRUSPNB was noted (39% false negative). When an abnormality on either DRE, TRUS or TRUSPNB was observed, the sensitivity was 65%. The specificity was 89% when all three tests were abnormal. It would appear that preoperative assessment of tumor location is inadequate with the current modalities available. There may, however, be subsets of patients which would benefit by tumor location utilizing DRE, TRUS and TRUSPNB.