S&T-58 WHY DO SOME PATIENTS MAKE PRIMARILY CALCIUM OXALATE MONOHYDRATE VERSUS DIHYDRATE STONES?

INTRODUCTION AND OBJECTIVES: A major concern with transrectal biopsy (TRBx) is that the anterior portion of the prostate gland, including the anterior peripheral and transition zones is difficult to target by standard TRBx, particularly for larger glands. A recent study has assessed simulated biopsy schemes using threedimensional reconstructions of actual prostate cancer (PCa) specimens, and suggested that nearly all PCas with a tumor volume of >0.5 ml can be detected by 14-18 TRBx cores using needle with longer cutting length. The purpose of this study is to compare the detection rate of PCa using a novel Tru-Cut needle with 25 mm cutting length with that of a conventional needle with 17 mm cutting length in TRBx. METHODS: We cooperated with biopsy maker, TSK company, and developed a novel Tru-Cut biopsy needle with a 25 mm cutting length. A total of 426 patients underwent TRBx by the novel needle (group 25 mm). Complications that occurred (hematuria, urinary retention, rectal bleeding, and fever) were evaluated, and pain during biopsy was assessed using the Face scale. The biopsy tissue on the slides was scanned into a computer, and the length of the tissue was measured using the software ImageJ. The complications, pain on biopsy, tissue length, and detection rate of PCa were compared to those of 288 patients who underwent TRBx by a conventional needle with 17 mm cutting length (group 17 mm). RESULTS: Complications and values on the pain scale did not differ significantly between the groups. The length of tissue taken from the mid-portion of the prostate was significantly longer in group 25 mm than in group 17 mm (16.30 mm vs 18.53 mm, P < 0.001). The detection rate of PCa within the prostate-specific antigen (PSA) gray zone was significantly higher in group 25 mm than in group 17 mm (49.48% vs 39.77%, p1⁄40.044). CONCLUSIONS: The novel Tru-Cut biopsy needle is safe, and can be used to acquire a longer prostate tissue specimen. Use of the novel Tru-Cut needle with 25 mm cutting length in transrectal prostate biopsy significantly improved the detection rate of PCa within the PSA gray zone.