Significance of routine transition zone biopsies in Japanese men undergoing transrectal ultrasound-guided prostate biopsies

The objective of this study was to evaluate the clinical significance of additional routine transition zone (TZ) biopsies in Japanese men undergoing transrectal ultrasound (TRUS)-guided systematic 8-core peripheral zone (PZ) biopsies.

Between October 2002 and December 2004, a total of 788 consecutive patients underwent TRUS-guided systematic biopsy of the prostate for the fi rst time. As a rule, 10 cores were taken from each patient; that is, 8 cores from the PZ, including the standard sextant cores and 2 cores from the anterior lateral horns, and 2 additional cores from the bilateral TZ. The cancer detection rate was calculated according to several parameters. We also assessed the disease extent on radical prostatectomy specimens according to the cancer location within the biopsy specimens.

Prostate cancer was detected by 10-core biopsies in 209 (26.5%) of the 788 patients, and 11 of these patients had positive cores only in the TZ; that is, the increase in cancer detection rate by sampling two additional cores from the TZ was 5.3%. Among 209 patients diagnosed as having prostate cancer, radical prostatectomy without any neoadjuvant therapy was performed in 59 patients with positive biopsy cores in the PZ, 7 in the TZ and 32 in both the PZ and TZ. Patients with positive cores in both zones showed significantly less favorable characteristics, indicating more advanced disease than that in those with positive cores in either zone.

Routine TZ biopsy did not significantly increase the detection rate of prostate cancer; however, the anatomical location of positive biopsy cores could provide additional information concerning disease extension in patients undergoing radical prostatectomy.