ORIGINAL ARTICLE Potential predictive factors of positive prostate biopsy in the Japanese population Katsumi Shigemura Æ Soichi Arakawa Æ Kunito Yamanaka Æ Nobuo Yasui Æ Shigeji Matsubara Æ Takahiro Iwamoto Æ Nobuo Kataoka Æ Keiji Yuien Æ Masato Fujisawa Received: 31 December 2006 / Accepted: 28 March 2007 / Published online: 4 July 2007 Ó Springer Science+Business Media B.V. 2007 Abstract Introduction There are numerous arguments for the predictive factors of positive prostate biopsies, differing according to race and region. This study aimed to determine predictive factors for a positive prostate biopsy in East Asian, especially Japanese men, using clinical, laboratory, and transrectal ultra- sound (TRUS) findings. Methods Data were collected from 466 men who underwent a prostate biopsy for suspected prostate cancer. Variables analyzed including age, digital rectal examination (DRE) findings, prostate-specific antigen (PSA) level, PSA density, prostate volume, and TRUS findings. Logistic regression analysis and the Mann–Whitney U test were used for this study. Results Logistic regression analysis showed that significant predictors for a positive prostate biopsy for all patients were positive DRE results, prostate volume, and hypoechoic lesions on TRUS. Especially in the patients with PSA levels <10 ng/ml, the significant predictor for positive biopsy was prostate volume. The Mann–Whitney U test showed that significant predictors for a positive prostate biopsy in all patients were PSA density >0.15, positive DRE results, and prostate volume <25 cm 3 . Especially in patients with PSA levels <10 ng/ml, significant predictors for a positive prostate biopsy were prostate volume <25 cm 3 and PSA density >0.15. Additionally, even if the data were confined to those patients with seven or more core biopsies, all the predictive factors shown in all patients were significant predictors in this category. Conclusion This study investigated potential predic- tors for positive prostate biopsy and demonstrated that prostate volume was an independent predictive factor for positive prostate biopsy in patients with PSA levels <10 ng/ml. In the future, we may be able to use our findings to create a nomogram for predicting positive prostate biopsy in Japanese men. Keywords Prostate biopsy  Predictive factor for positive prostate biopsy  Prostate volume Introduction Prostate cancer is one of the most common malignan- cies in men and is the second leading cause of cancer death of men in the United States [1]. The use of prostate-specific antigen (PSA) testing has contributed K. Shigemura  K. Yamanaka  N. Yasui  S. Matsubara  T. Iwamoto  N. Kataoka  K. Yuien Department of Urology, Nishiwaki Municipal Hospital, Nishiwaki, Japan K. Shigemura (&)  S. Arakawa  M. Fujisawa Division of Urology, Department of Organ Therapeutics, Faculty of Medicine, Kobe University Graduate School of Medicine, 7-5-1, Kusunoki-cho, Chuo-ku, Kobe 650- 0017, Japan e-mail: katsumiatlanta@hotmail.com 123 Int Urol Nephrol (2008) 40:91–96 DOI 10.1007/s11255-007-9219-5