www.kjurology.org http://dx.doi.org/10.4111/kju.2012.53.3.149 Urological Oncology Clinical Significance of Free-to-Total Prostate-Specific Antigen (PSA) Ratio in Advanced Prostate Cancer Patients with PSA Less than 0.1 ng/ml after Hormone Treatment Dae Il Kim, Jae Mann Song, Hyun Chul Chung Department of Urology, Yonsei University Wonju College of Medicine, Wonju, Korea Purpose: We analyzed the pattern of change in the free-to-total prostate-specific anti- gen (f/t PSA) ratio and the progression to castration-resistant prostate cancer (CRPC) in patients with advanced prostate cancer who received hormone treatment and whose PSA nadir was below 0.1 ng/ml. Materials and Methods: We retrospectively analyzed the medical records of 52 patients with advanced prostate cancer. All patients were treated with maximum androgen blockade (gonadotrophin-releasing hormone agonist and anti-androgen agents). The patients were divided into two groups: those with a nadir f/t PSA ratio above 60% and those with a nadir f/t PSA ratio of 60% or below. Age, initial PSA, clinical stage, lymph node metastasis, bone metastasis, and follow-up data, including PSA, free PSA, and f/t PSA ratio, were collected. The Mann-Whitney U-test, Fisher exact test, chi-square test, Kaplan-Meier survival analysis, and log rank test were used. Results: There were 24 patients in the group with a nadir f/t PSA ratio above 60% and 28 patients in the group with a nadir f/t PSA ratio of 60% or below. After hormone ther- apy, the median f/t PSA ratio in each group increased from 37% and 34% at 3 months to 75% and 60% at 6 months, respectively. At 9 months, however, the f/t PSA ratio in- creased to 80% in the group with a nadir f/t PSA ratio above 60%, whereas it decreased to 31% in the group with a nadir f/t PSA ratio of 60% or below. From 9 to 15 months, the f/t PSA ratio showed a tendency to decrease (75 to 37% and 27 to 20%, respectively). The progression to CRPC was significantly different between the two groups (10 vs. 24). Conclusions: Progression to CRPC was significantly higher in the group with a lower f/t PSA ratio. Additionally, the pattern of change in the f/t PSA ratio was significantly different after 9 months. Collectively, the f/t PSA ratio can be used as an additional marker for prognosis of hormone treatment. Key Words: Hormone replacement therapy; 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 14 August, 2011 accepted 25 October, 2011 Corresponding Author: Hyun Chul Chung Department of Urology, Yonsei University Wonju College of Medicine, 20 Ilsan-ro, Wonju 220-701, Korea TEL: +82-33-741-0654 FAX: +82-33-748-3804 E-mail: chc7174@yonsei.ac.kr INTRODUCTION Prostate cancer is the most common cancer in the United States [1]. In Korea, prostate cancer is the fifth most com- mon malignancy in men [2]. Because of prostate-specific antigen (PSA)-based screening, the clinical stage of newly diagnosed prostate cancer has been migrating downward in the United States [3]. According to the American Cancer Society-National Prostate Cancer Detection Project, the proportion of locally advanced (clinical state T3) and meta- static (stage T1-4N0-1M1) prostate cancer (advanced pros- tate cancer) was reduced to less than 5% of all newly diag- nosed cancers [4]. In Korea, however, more than half of newly diagnosed prostate cancer is of an advanced stage Korean Journal of Urology Ⓒ The Korean Urological Association, 2012 149 Korean J Urol 2012;53:149-153