Detection of prostate cancer: A comparative study of the diagnostic efficacy of sextant transrectal versus sextant transperineal biopsy

Objectives. The optimal biopsy strategy for the detection of prostate cance r still needs to be established, since a considerable proportion of clinica lly significant cancers remains undiagnosed on routine sextant transrectal biopsy. To assess the efficacy of transperineal biopsy to detect prostate c ancer, we compared this approach to systematic sextant transrectal biopsy i n a simulation experiment. Methods. Ultrasound-guided sextant transverse (transrectal) biopsy and subs equent sextant longitudinal (transperineal) biopsy were performed on 40 rad ical prostatectomy specimens of patients with (transrectal) biopsy-detected prostate cancer. Conditions were simulative and may not be completely anal ogous to clinical settings. Ultrasound-determined prostate volume, biopsy t umor involvement, number of cores with cancer, and tumor volume were determ ined. Detailed mapping of radical prostatectomy specimens provided insight into the representativeness of the biopsy techniques. Results. Of 40 cancers, 33 (82.5%) were redetected by the transperineal app roach; 29 (72.5%) were detected by repeated transrectal biopsies. For both approaches, the tumor volume of the undiagnosed cancers was significantly s maller (P <0.01) and the prostate volume was significantly larger (P <0.01) than in the redetected ones. Between the two approaches, no difference was found for either of the variables determined in the redetected cancers. Pr ostate maps clarified that transperineal undiagnosed tumors were either sma ll (0.2 cm(3) or less) or notably located at the prostatic base. Conclusions. The biopsy procedure in which the biopsy needles enter the pro state at the apex for a longitudinal direction may efficiently sample the p rostatic peripheral zone. Since the experiment was artificial in design, ca ution should be observed in extrapolating-these results to patient settings . UROLOGY 56: 617-621, 2000. (C) 2000, Elsevier Science Inc.