Transperineal extended biopsy improves the clinically significant prostate cancer detection rate: A comparative study of 6 and 12 biopsy cores

Background: We evaluated the improvement in the rate of prostate cancer detection when using a 12-core transperineal biopsy protocol including transitional zone biopsy.

Methods: Between April 2003 and November 2004, 247 consecutive men underwent transperineal systemic 12-core biopsy of the prostate. Six cores were obtained at the peripheral zone, four at the transitional zone and two at the apex. We examined the cancer detection rate in each of the 12 cores, and also determined the improvement of cancer detection resulting from the extensive 12-core versus standard 6-core biopsy.

Results: Using the extensive 12-core biopsy, prostate cancer was detected in 98 cases (39.7%). Prostate-specific antigen (PSA), PSA density, the positive rate in digital rectal examination and transrectal ultrasound findings were significantly higher in the prostate cancer group than in the non-prostate cancer group, and prostate volume was larger in non-prostate cancer group. Every site showed almost the same positive rate, between 17.8 and 21.5%. There were 20 cases which were positive in the extended biopsy, but negative in the sextant. The detection improved significantly (20.4%). The improvement of cancer detection in extended biopsy was better in men with PSA levels of 10 ng/mL or less (28.9%), PSA density 0.3 or less (25.8%), negative digital rectal examination (23.3%), and negative transrectal ultrasound (21.6%). Of these twenty patients, no cases with insignificant tumor were detected in the six prostatectomy cases. In particular, three cases of the six were transitional-zone-only cancer.

Conclusion: Transperineal extended 12-core biopsy including 4 transitional zone cores is a more useful procedure than transperineal 6-core biopsy. Routine transitional zone biopsy, that is different from transrectal biopsy, might be useful for detecting biologically significant cancer.