Influence of nonregional lymph node metastasis as a prognostic factor in metastatic prostate cancer patients

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 metastasis 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 influence 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 biology, additional molecular and genetic studies are needed.