www.kjurology.org http://dx.doi.org/10.4111/kju.2012.53.10.673 Urological Oncology Influence of Nonregional Lymph Node Metastasis as a Prognostic Factor in Metastatic Prostate Cancer Patients Seok Cho, Sung Gu Kang, Bum Sik Tae, Jun Cheon Department of Urology, Korea University Anam Hospital, Seoul, Korea Purpose: In advanced prostate cancer, malignant cells generally tend to spread into the bone, and metastasis into nonregional lymph nodes (NRLNs) at the time of initial diagnosis is relatively rare. We investigated the prognostic significance of NRLN meta- stasis in patients receiving hormonal therapy and chemotherapy. Materials and Methods: From February 2005 to August 2011, we identified 105 patients who had metastatic prostate cancer. First, we assessed the prognostic effect of NRLN metastasis on the prostate-specific antigen response through logistic regression and the progression-free time to castration-resistant prostate cancer (CRPC) by using the Cox proportional hazard regression model. Second, we investigated the prognostic in- fluence of NRLN metastasis on the chemotherapy response through logistic regression and on cancer-specific survival of CRPC patients receiving chemotherapy by using Cox proportional analysis. Results: Of these 105 patients, 12 patients (11.4%) had only NRLN metastases without bone metastases. Progression-free time to CRPC was significantly less in patients with NRLN metastases by Cox proportional hazard regression multivariate analysis (p=0.020). However, NRLN metastasis was not an independent factor for predicting the response to chemotherapy in CRPC patients, and NRLN metastasis did not reduce cancer-specific survival in the multivariate analysis. Conclusions: Twelve (11.4%) of 105 patients with NRLN metastases had lymph node metastases without bone metastases. In addition, NRLN metastasis was a significant prognostic factor for predicting reduced progression-free time to CRPC. Thus, although we speculate that prostate cancer with NRLN metastasis exhibits unique tumor biol- ogy, additional molecular and genetic studies are needed. Key Words: Lymphatic metastasis; Prognosis; Prostatic neoplasm 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 5 June, 2012 accepted 31 July, 2012 Corresponding Author: Jun Cheon Department of Urology, Korea University Anam Hospital, 73 Inchon-ro, Seongbuk-gu, Seoul 136-705, Korea TEL: +82-2-920-5367 FAX: +82-2-928-7864 E-mail: jcheon@korea.ac.kr INTRODUCTION Prostate cancer is the most commonly diagnosed nonskin malignancy in men and is the second leading cause of can- cer-related death in the United States [1]. The incidence of prostate cancer is also rapidly increasing in Korea [2]. In the United States, approximately 90% of patients with prostate cancer are diagnosed with early-stage disease, whereas 4% present with metastatic disease. Although early-stage prostate cancer is typically cured with radical surgery, managing prostate cancer in patients with distant metastasis is challenging, and the prognosis is poor, with an average survival of 24 to 48 months [3,4]. Previous reports have shown that localized prostate can- cer has a heterogeneous natural history, moving from in- dolent to aggressive tumor [5,6]. However, prostate cancer with metastasis at the time of initial diagnosis is relatively rare, and few reports have described the biology or natural history of metastatic prostate cancer. In advanced prostate cancer, malignant cells tend to spread into bone and lymph nodes [7]. Regional lymph node metastasis is common in prostate cancer; however, metastasis into nonregional Korean Journal of Urology Ⓒ The Korean Urological Association, 2012 673 Korean J Urol 2012;53:673-679