www.kjurology.org DOI:10.4111/kju.2011.52.3.166 Urological Oncology Predictive Factors for Prostate Cancer in Biopsy of Patients with Prostate-Specific Antigen Levels Equal to or Less Than 4 ng/ml Hyoung Woo Kim, Young Hwii Ko1, Seok Ho Kang1, Jeong Gu Lee1 Department of Urology, Sahmyook Medical Center, 1College of Medicine, Korea University, Seoul, Korea Purpose: This study was conducted to identify the predictive factors for prostate cancer in patients with prostate-specific antigen (PSA) levels equal to or less than 4 ng/ml. Materials and Methods: A retrospective study of medical records was conducted on 292 patients with initial serum PSA ≤4 ng/ml among 2,305 patients who underwent pros- tate biopsy from January 2003 to December 2008. Prostate biopsy was performed on patients with PSA ≤4 ng/ml in the case of abnormal findings in the digital rectal exami- nation (DRE) or transrectal ultrasonography (TRUS) or in those with a PSA level higher than the age-adjusted PSA levels. The patients were divided into the group diagnosed with prostate cancer and the non-prostate-cancer group. Subsequently, the variables of the two groups were compared. Results: The patients’ mean age was significantly higher in the prostate cancer group (n=28) than in the non-prostate-cancer group (n=264; p=0.033). In addition, for the pa- tients with a PSA range of 2.0-2.9 ng/ml, their age (p=0.049) and PSA density (PSAD; p=0.042) were significantly higher and the prostate volume (p=0.028) was significantly smaller in the prostate cancer group than in the non-prostate-cancer group. Conclusions: Of the patients with PSA ≤4 ng/ml, the age of the patients who showed abnormal findings in the DRE or TRUS or who had a PSA level higher than the age-ad- justed PSA level was a significant predictive factor for prostate cancer. In particular, for the PSA range of 2.0-2.9 ng/ml, a thorough screening test for prostate cancer was required if the patients had conditions such as higher age, smaller prostate, and higher PSAD. Key Words: Prostate-specific antigen; Prostatic neoplasms This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Article History: received 27 December, 2010 accepted 28 February, 2011 Corresponding Author: Jeong Gu Lee Department of Urology, Korea University Anam Hospital, 126-1, 5-ga, Anam-dong, Sungbuk-gu, Seoul 136-705, Korea TEL: +82-2-920-5683 FAX: +82-2-928-7864 E-mail: jeongkl@kumc.or.kr INTRODUCTION Prostate cancer is one of the most common malignancies among men and was in first place in United States for male cancer morbidity and in second place for cancer mortality, next to lung cancer, in 2009 [1]. Increasing mortality rates due to prostate cancer have been observed worldwide. In Korea, prostate cancer incidence increased up to 28.2% be- tween 1996-1998 and 1999-2001, and mortality increased 12.7-fold over a 20-year period [2]. 　Because prostate cancer generally progresses impercep- tively, patients are unlikely to seek medical help during the early stages. For these reasons, screening programs aimed Korean Journal of Urology Ⓒ The Korean Urological Association, 2011 at early detection have been developed [3,4]. The serum pro- state-specific antigen (PSA) level is among the best of the screening tools available in medicine today and is recognized as the best marker for early detection. The most challenging problem in the use of PSA as the screening test, however, is that PSA lacks specificity. Because the PSA level is organ- specific rather than tumor-specific, it also increases in cases of benign prostatic hyperplasia and prostatic inflammation. Since the introduction of the prostate cancer screening test with PSA, much research has been published on the deter- mination of the PSA cutoff value for prostate biopsy in pa- tients with increased PSA. At present, a PSA level of 4 ng/ml is widely used as the cutoff value for the performance of a 166 Korean J Urol 2011;52:166-171