METastasis Reporting and Data System for Prostate Cancer as a Prognostic Imaging Marker in Castration-resistant Prostate Cancer

Whole-body diffusion-weighted magnetic resonance imaging reflects therapeutic response of osseous and extra-osseous lesions, and the signal may reflect the activity of metastatic lesions of castration-resistant prostate cancer. METastasis Reporting and Data System for Prostate Cancer score of whole-body diffusion-weighted magnetic resonance imaging is advantageous to assess the prognosis for castration-resistant prostate cancer. Background: METastasis Reporting and Data System for Prostate Cancer (MET-RADS-P) has been proposed as a standard of data acquisition and interpretation for whole-body diffusion-weighted magnetic resonance imaging (WB-DWI) performed in men with advanced prostate cancer. The aim of this study is to demonstrate the clinical significance of the scores in castration-resistant prostate cancer (CRPC). Materials and Methods: We retrospectively evaluated WB-DWI obtained from 72 patients with CRPC between 2014 and 2017, when disease progression was suspected at the time of starting a new line of anticancer therapy. Twenty-five (35%) and 30 (42%) patients had a treatment history that included taxane-based chemotherapy and new hormonal drugs, respectively. Results: Active bone metastases were identified in 60 patients (83%; number of bone metastasis = 0, 1-2, 3-5, 6-10, and > 10: n = 12 [17%], 20 [28%], 11 [15%], 1 [1%], and 28 [39%], respectively). Progressive lymph node and visceral metastases were identified in 10 (14%) and 4 (6%), respectively. During the median follow-up period of 24 months, 36 (50%) died of prostate cancer. Cancer-specific survival (CSS) was significantly stratified according to the MET-RADS-P scores of osseous metastatic burden and the presence of visceral metastasis (P < .0001). Multivariate analysis revealed that high osseous metastatic burden (> 10) and the presence of visceral metastasis were significant indicators of shorter CSS (P = .0036 and P = .0017, respectively). Conclusions: The extent of bone metastasis and the presence of visceral metastasis on WB-DWI were associated with a shorter CSS in CRPC. MET-RADS-P score can be a prognostic imaging biomarker for CRPC. (C) 2019 Elsevier Inc. All rights reserved.