title: Clinically low-risk prostate cancer: evaluation with transrectal doppler ultrasound and functional magnetic resonance imaging.
abstract: OBJECTIVE
  To evaluate transrectal ultrasound, amplitude Doppler ultrasound, conventional T2-weighted magnetic resonance imaging, spectroscopy and dynamic contrast-enhanced magnetic resonance imaging in localizing and locally staging low-risk prostate cancer.
  
  
  BACKGROUND
  Prostate cancer has been diagnosed at earlier stages and the most accepted classification for low-risk prostate cancer is based on clinical stage T1c or T2a, Gleason score ≤6, and prostate-specific antigen (PSA) ≤10 ng/ml.
  
  
  METHODS
  From 2005 to 2006, magnetic resonance imaging was performed in 42 patients, and transrectal ultrasound in 26 of these patients. Seven patients were excluded from the study. Mean patient age was 64.94 years and mean serum PSA was 6.05 ng/ml. The examinations were analyzed for tumor identification and location in prostate sextants, detection of extracapsular extension, and seminal vesicle invasion, using surgical pathology findings as the gold standard.
  
  
  RESULTS
  Sixteen patients (45.7%) had pathologically proven organ-confined disease, 11 (31.4%) had positive surgical margin, 8 (28.9%) had extracapsular extension, and 3 (8.6%) presented with extracapsular extension and seminal vesicle invasion. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy values for localizing low-risk prostate cancer were 53.1%, 48.3%, 63.4%, 37.8% and 51.3% for transrectal ultrasound; 70.4%, 36.2%, 65.1%, 42.0% and 57.7% for amplitude Doppler ultrasound; 71.5%, 58.9%, 76.6%, 52.4% and 67.1% for magnetic resonance imaging; 70.4%, 58.7%, 78.4%, 48.2% and 66.7% for magnetic resonance spectroscopy; 67.2%, 65.7%, 79.3%, 50.6% and 66.7% for dynamic contrast-enhanced magnetic resonance imaging, respectively. Sensitivity, specificity, PPV, NPV and accuracy values for detecting extracapsular extension were 33.3%, 92%, 14.3%, 97.2% and 89.7% for transrectal ultrasound and 50.0%, 77.6%, 13.7%, 95.6% and 75.7% for magnetic resonance imaging, respectively. For detecting seminal vesicle invasion, these values were 66.7%, 85.7%, 22.2%, 97.7% and 84.6% for transrectal ultrasound and 40.0%, 83.1%, 15.4%, 94.7% and 80.0% for magnetic resonance imaging.
  
  
  CONCLUSIONS
  Although preliminary, our results suggest that imaging modalities have limited usefulness in localizing and locally staging clinically low-risk prostate cancer.
authors: Faculdade de Medicina da Universidade de São Paulo--Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo, São Paulo, Brazil.
authors: Maria Inês
authors: MI
authors: Novis
authors: Ronaldo Hueb
authors: RH
authors: Baroni
authors: Luciana Mendes de Oliveira
authors: LM
authors: Cerri
authors: Romulo Loss
authors: RL
authors: Mattedi
authors: Carlos Alberto
authors: CA
authors: Buchpiguel
mesh_terms: D000368:Aged; D001706:Biopsy; D003287:Contrast Media; D006801:Humans; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging / Q000379:methods*; D011237:Predictive Value of Tests; D017430:Prostate-Specific Antigen / Q000032:analysis; D011468:Prostatectomy; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology*; D012307:Risk Factors; D018608:Ultrasonography, Doppler / Q000379:methods
chemical_list: D003287:Contrast Media; D017430:Prostate-Specific Antigen