title: Candidate selection for quadrant-based focal ablation through a combination of diffusion-weighted magnetic resonance imaging and prostate biopsy.
abstract: OBJECTIVE
  To identify prostatic quadrants that could be preserved without intervention, using diffusion-weighted magnetic resonance imaging (DWI) and extended core biopsy, as a step toward implementation of quadrant-based focal ablation with potential preservation of erectile and ejaculatory functions, based on comparisons with unilateral hemi-gland ablation.
  
  
  METHODS
  We conducted a prebiopsy DWI study including 648 quadrants in 162 men who underwent 14-core biopsy including anterior sampling and radical prostatectomy (RP) for localised cancer. Imaging and pathology were analysed on a quadrant basis. Each quadrant was assessed through four-core sampling. Predictive performance of DWI and biopsy for quadrant status was analysed.
  
  
  RESULTS
  On RP specimens, 170 anterior (52.5%) and 172 posterior quadrants (53.1%) harboured significant cancer. Negative predictive values of DWI, biopsy, and their combination for significant cancer were 79.7%, 70.6%, and 91.1%, respectively, in anterior quadrants, and 78.5%, 81.3%, and 91.7%, respectively, in posterior quadrants. DWI incrementally improved the negative predictive values of biopsy in anterior (P < 0.001) and posterior quadrants (P = 0.025), without untoward impacts on positive predictive values. Negative findings on both DWI and biopsy were identified in posterior quadrants of 109 sides (33.6%), but in entire hemi-glands of 54 sides (16.7%).
  
  
  CONCLUSIONS
  The combination of DWI and 14-core biopsy including anterior sampling efficiently identifies quadrants without significant cancer in men with localised prostate cancer; the remaining quadrants, therefore, could be potential candidate areas for focal ablation. Focal therapy designed based on quadrant-based assessment could be superior to unilateral hemi-gland ablation for preservation of posterior quadrants and retaining of sexual function in more sides.
authors.affiliation: Department of Urology, Tokyo Medical and Dental University Graduate School, Tokyo, Japan.
authors.forename: Yoh
authors.initials: Y
authors.lastname: Matsuoka
authors.affiliation: Department of Urology, Tokyo Medical and Dental University Graduate School, Tokyo, Japan.
authors.forename: Noboru
authors.initials: N
authors.lastname: Numao
authors.affiliation: Department of Urology, Tokyo Medical and Dental University Graduate School, Tokyo, Japan.
authors.forename: Kazutaka
authors.initials: K
authors.lastname: Saito
authors.affiliation: Department of Radiology, Ochanomizu Surugadai Clinic, Tokyo, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Tanaka
authors.affiliation: Department of Pathology, Tokyo Medical and Dental University Graduate School, Tokyo, Japan.
authors.forename: Jiro
authors.initials: J
authors.lastname: Kumagai
authors.affiliation: Department of Urology, Tokyo Medical and Dental University Graduate School, Tokyo, Japan.
authors.forename: Soichiro
authors.initials: S
authors.lastname: Yoshida
authors.affiliation: Department of Urology, Tokyo Medical and Dental University Graduate School, Tokyo, Japan.
authors.forename: Junichiro
authors.initials: J
authors.lastname: Ishioka
authors.affiliation: Department of Urology, Tokyo Medical and Dental University Graduate School, Tokyo, Japan.
authors.forename: Fumitaka
authors.initials: F
authors.lastname: Koga
authors.affiliation: Department of Urology, Tokyo Medical and Dental University Graduate School, Tokyo, Japan.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Masuda
authors.affiliation: Department of Urology, Tokyo Medical and Dental University Graduate School, Tokyo, Japan.
authors.forename: Satoru
authors.initials: S
authors.lastname: Kawakami
authors.affiliation: Department of Urology, Tokyo Medical and Dental University Graduate School, Tokyo, Japan.
authors.forename: Yasuhisa
authors.initials: Y
authors.lastname: Fujii
authors.affiliation: Department of Urology, Tokyo Medical and Dental University Graduate School, Tokyo, Japan.
authors.forename: Kazunori
authors.initials: K
authors.lastname: Kihara
mesh_terms: D055011:Ablation Techniques / Q000379:methods; D000368:Aged; D000369:Aged, 80 and over; D001706:Biopsy / Q000379:methods*; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008297:Male; D008875:Middle Aged; D011467:Prostate / Q000473:pathology* / Q000601:surgery*; D011468:Prostatectomy / Q000379:methods; D011471:Prostatic Neoplasms / Q000453:epidemiology / Q000473:pathology* / Q000601:surgery*
keywords: diffusion-weighted MRI; focal therapy; prostate biopsy; prostate cancer; prostatectomy; quadrant ablation