-Original-

Random Systematic Sextant Biopsy Versus Power Doppler Ultrasound-guided Target Biopsy in the Diagnosis of Prostate Cancer: Positive Rate and Clinicopathological Features

Go Kimura, Taiji Nishimura, Ryoji Kimata, Yuka Saito and Kazuhiro Yoshida

Department of Urology, Nippon Medical School

Purpose: To determine the efficacy of power Doppler ultrasound (PDU)in the diagnosis of prostate cancer, the rate of detection of cancer with PDU-guided target biopsy and sextant biopsy, the clinicopathological features of cancer positive specimens, and the relation between these two findings were studied.
Methods: From January 1998 through March 2000, 302 men suspected to have prostate cancer underwent sextant biopsy in association with additional PDU-guided target biopsy. Cases with positive biopsy results were divided into 9 groups as follows: T0: sextant biopsy was positive, but target biopsy was negative; S0: all sextant biopsies were negative, but target biopsy was positive; S1∼S6: both sextant biopsy and target biopsy were positive (number indicates number of positive sextant biopsy); Tx: sextant biopsy was positive, but no target biopsy was performed owing to a lack of echogenic abnormalities. The Gleason score (GS) and percent organ confined disease (%OCD) were compared between these 9 groups.
Results: Cancer was pathologically detected in 143 of 302 patients (47.4%). PDU detected 39 of 49 digital rectal examination-negative cancers (79.6%) and 5 of 13 transrectal ultrasound-negative isoechoic cancers (38.5%). Of 143 biopsy-positive cases, 6 were in the T0 group (4.2%), 10 in S0 (7.0%), 119 in S1∼S6 (83.2%), and 8 in Tx (5.6%). Target biopsy missed 14 (sum of T0 and Tx) cancers, and sextant biopsy missed 10 (S0). The average GS in the Tx group was significantly lower than that in the other groups; consequently, the %OCD was significantly higher. Retrospective analysis revealed that the failure to obtain cancer tissue in 4 of the 6 cases in the T0 group is most likely due to technical failure in obtaining specimens. The overall sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of PDU were 90.2%, 77.4%, 78.2%, 89.8% and 83.4%, respectively.
Conclusion: PDU in association with sextant biopsy is a useful tool for increasing the rate of detection of prostate cancer. Further advances in ultrasound technology may enable the detection of prostate cancer by target biopsy alone and consequently may reduce the number of unnecessary biopsies. However, PDU-guided target biopsy alone is insufficient for cancer detection at the present time because of possible technical failure in obtaining specimens and the existence of PDU-negative cancer. Although more evidence is required, PDU-negative cancer is suggested to be less aggressive clinically, possibly justifying a watch and wait policy.

J Nippon Med Sch 2005; 72: 262-269

Keywords
prostate cancer, power Doppler ultrasound, diagnosis, biopsy

Correspondence to
Taiji Nishimura, Department of Urology, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-ku, Tokyo 113-8603, Japan
gokimura@nms.ac.jp

Received, May 26, 2005
Accepted, July 13, 2005