title: Diffusion-weighted MRI as a potential imaging biomarker reflecting the metastatic potential of upper urinary tract cancer.
abstract: OBJECTIVE
  To evaluate the role of diffusion-weighted MRI (DW-MRI) as an imaging biomarker for upper urinary tract cancer (UUTC) that has already metastasized or will metastasize soon.
  
  
  METHODS
  61 patients clinically diagnosed with UUTC were prospectively enrolled in this study. All the patients underwent MRI, including DW-MRI, prior to any interventions. Correlations between apparent diffusion coefficient (ADC) and other clinicopathological variables, including metastasis-free survival, were analysed.
  
  
  RESULTS
  Median follow-up period was 938 days. Of the 61 patients, 12 had any metastases at the initial diagnosis. 11 patients developed metastases during the follow-up period. These 23 patients were categorized as "Metastatic". Of the remaining 38 patients, 35 with a follow-up period longer than 400 days were categorized as "Localized". ADC was significantly lower in the Metastatic category than in the Localized (p = 0.0002) category. Multivariate analysis of pre-operative variables identified ADC (cut-off value, 1.08 × 10(-3) mm(2) s(-1)) and clinical T stage based on T2 weighted MRI as an independent predictive factor of metastatic UUTC. 46 patients without any metastases during the initial diagnosis were stratified into a high-risk group (16 patients with low ADC and clinical T3-4) and a low-risk group (30 patients with high ADC or clinical Ta-2). The 3-year metastasis-free survivals were 45% and 93%, respectively.
  
  
  CONCLUSIONS
  In the current study, UUTC with lower ADC value is more likely to have metastatic potential. Incorporating ADC with clinical T stage helps to differentiate metastatic UUTC at the initial diagnosis.
  
  
  CONCLUSIONS
  DW-MRI is a potential imaging biomarker reflecting metastatic propensity of UUTC.
authors: 1 Department of Urology, Tokyo Medical and Dental University Graduate School, Tokyo, Japan.
authors: Y
authors: Y
authors: Uchida
authors: S
authors: S
authors: Yoshida
authors: S
authors: S
authors: Kobayashi
authors: F
authors: F
authors: Koga
authors: J
authors: J
authors: Ishioka
authors: S
authors: S
authors: Satoh
authors: C
authors: C
authors: Ishii
authors: H
authors: H
authors: Tanaka
authors: Y
authors: Y
authors: Matsuoka
authors: N
authors: N
authors: Numao
authors: K
authors: K
authors: Saito
authors: H
authors: H
authors: Masuda
authors: Y
authors: Y
authors: Fujii
authors: K
authors: K
authors: Kihara
mesh_terms: D014408:Biomarkers, Tumor; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D053208:Kaplan-Meier Estimate; D007680:Kidney Neoplasms / Q000473:pathology; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009367:Neoplasm Staging; D001749:Urinary Bladder Neoplasms / Q000473:pathology; D014571:Urologic Neoplasms / Q000175:diagnosis / Q000401:mortality / Q000473:pathology*
chemical_list: D014408:Biomarkers, Tumor