Prostate biopsy outcome using 29 mm cutting length.

Objectives: The aim of the study was to compare the prostate biopsy outcome by using either standard or extended cutting length of the needles.

Material And Methods: A total of 74 consecutive prostates from radical prostatectomy were used. Two sextant biopsies were performed ex vivo. We developed a precise simulation of a transrectal biopsy procedure using ultrasound for guiding the needle. In the first set of biopsies an 18-gauge tru cut needle with 19 mm cutting length, powered by a automatic biopsy gun was used. In the second set a single use gun with an 18-gauge end-cutting needle and 29 mm cutting length was used.

Results: In the set of sextant biopsies using 19 mm cutting length 49 (66%) carcinomas were found. In the set of sextant biopsies using 29 mm cutting length 58 (78%) of the tumors were detected. 24 (32%) prostates showed tumor in the transition zones, but there was no transition-zone-only cancer in this study. Nevertheless taking longer cores led to an improvement in prostate cancer detection of 18%.

Conclusions: In this ex vivo setting the use of 29 mm cutting length for prostate biopsy led to an significant improvement in cancer detection. As we found the end-cutting needle not suitable for use in the patient, these results support the idea to develop a longer tru cut needle and corresponding gun for further clinical investigations.