title: Multiparametric magnetic resonance imaging for prostate cancer improves Gleason score assessment in favorable risk prostate cancer.
abstract: OBJECTIVE
  Magnetic resonance imaging (MRI) guidance may improve the accuracy of Gleason score (GS) determination by directing the biopsy to regions of interest (ROI) that are likely to harbor high-grade prostate cancer (CaP). The aim of this study was to determine the frequency and predictors of GS upgrading when a subsequent MRI-guided biopsy is performed on patients with a diagnosis of GS 6 disease on the basis of conventional, transrectal ultrasound-guided biopsy.
  
  
  METHODS
  A consecutive series of 245 men with a diagnosis of low-risk CaP (ie, cT1c, GS 6, prostate-specific antigen <10) based on transrectal ultrasound-guided biopsy was enrolled in an active surveillance protocol that used subsequent MRI-guided biopsy for confirmation of GS. ROIs were categorized on a scale of 1 to 5. The Artemis ultrasound-MRI fusion device was used to perform targeted biopsies of ROIs as well as systematic biopsies from a software-based 12-point map. Predictors of GS upgrading were analyzed using univariate and multivariate analyses.
  
  
  RESULTS
  Fusion biopsy resulted in 26% of patients having GS upgrading (GS 3+4 in 18%, 4+3 in 5%, and 8-9 in 3%). Of the 72% of patients with ROIs appropriate for targeting, targeted cores upgraded the GS in 18%, whereas systematic cores upgraded the GS in 24%. In patients without targeted biopsy, GS upgrading was seen in 14%. On multivariate analysis, a category 5 ROI was the most significant predictor of GS upgrading with an odds ratio of 10.56 (P < .01).
  
  
  CONCLUSIONS
  Nearly 25% of men with GS 6 CaP diagnosed by standard transrectal ultrasound biopsy may experience GS upgrading when a subsequent MRI-ultrasound fusion biopsy is performed. The most important single predictor of upgrading is a category 5 ROI on multiparametric MRI. GS upgrading may influence treatment decisions. Therefore, MRI-guided biopsy should be considered prior to formulating a management strategy in patients whose conventional biopsy reveals low-risk CaP.
authors.affiliation: Department of Radiation Oncology, University of California Los Angeles, Los Angeles, California. Electronic address: mkamrava@mednet.ucla.edu.
authors.forename: Mitchell
authors.initials: M
authors.lastname: Kamrava
authors.affiliation: Department of Radiation Oncology, University of California Los Angeles, Los Angeles, California.
authors.forename: Amar U
authors.initials: AU
authors.lastname: Kishan
authors.affiliation: Department of Radiology, University of California Los Angeles, Los Angeles, California.
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Margolis
authors.affiliation: Department of Pathology, University of California Los Angeles, Los Angeles, California.
authors.forename: Jiaoti
authors.initials: J
authors.lastname: Huang
authors.affiliation: Department of Urology, University of California Los Angeles, Los Angeles, California.
authors.forename: Fred
authors.initials: F
authors.lastname: Dorey
authors.affiliation: Department of Urology, University of California Los Angeles, Los Angeles, California.
authors.forename: Patricia
authors.initials: P
authors.lastname: Lieu
authors.affiliation: Department of Radiation Oncology, University of California Los Angeles, Los Angeles, California.
authors.forename: Patrick A
authors.initials: PA
authors.lastname: Kupelian
authors.affiliation: Department of Urology, University of California Los Angeles, Los Angeles, California.
authors.forename: Leonard S
authors.initials: LS
authors.lastname: Marks
mesh_terms: D019468:Disease Management; D006801:Humans; D061705:Image-Guided Biopsy / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D009367:Neoplasm Staging; D011379:Prognosis; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D012307:Risk Factors; D014463:Ultrasonography