title: MRI-guided focal laser ablation for prostate cancer followed by radical prostatectomy: correlation of treatment effects with imaging.
abstract: OBJECTIVE
  To correlate treatment effects of MRI-guided focal laser ablation in patients with prostate cancer with imaging using prostatectomy as standard of reference.
  
  
  METHODS
  This phase I study was approved by the Institutional Review Board. Three weeks prior to prostatectomy, five patients with histopathologically proven, low/intermediate grade prostate cancer underwent transrectal MRI-guided focal laser ablation. Per patient, only one ablation was performed to investigate the effect of ablation on the tissue rather than the effectiveness of ablation. Ablation was continuously monitored with real-time MR temperature mapping, and damage-estimation maps were computed. A post-ablation high-resolution T1-weighted contrast-enhanced sequence was acquired. Ablation volumes were contoured and measured on histopathology specimens (with a shrinkage factor of 1.15), T1-weighted contrast-enhanced images, and damage-estimation maps, and were compared.
  
  
  RESULTS
  A significant volume correlation was seen between the ablation zone on T1-weighted contrast-enhanced images and the whole-mount histopathology section (r = 0.94, p = 0.018). The damage-estimation maps and histopathology specimen showed a correlation of r = 0.33 (p = 0.583). On histopathology, the homogeneous necrotic area was surrounded by a reactive transition zone (1-5 mm) zone, showing neovascularisation, and an increased mitotic index, indicating increased tumor activity.
  
  
  CONCLUSIONS
  The actual ablation zone was better indicated by T1-weighted contrast-enhanced than by damage-estimation maps. Histopathology results highlight the importance of complete tumor ablation with a safety margin.
authors.affiliation: Department of Radiology, Radboud University Medical Center, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands. Joyce.Bomers@radboudumc.nl.
authors.forename: Joyce G R
authors.identifier: http://orcid.org/0000-0002-6037-6099
authors.initials: JGR
authors.lastname: Bomers
authors.affiliation: Department of Urology, Ziekenhuisgroep Twente, P.O. Box 546, 7550AM, Hengelo, The Netherlands.
authors.forename: Erik B
authors.initials: EB
authors.lastname: Cornel
authors.affiliation: Department of Radiology, Radboud University Medical Center, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands.|MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, Building Zuidhorst, P.O. Box 217, 7500 AE, Enschede, The Netherlands.
authors.forename: Jurgen J
authors.initials: JJ
authors.lastname: Fütterer
authors.affiliation: Department of Radiology, Radboud University Medical Center, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands.
authors.forename: Sjoerd F M
authors.initials: SFM
authors.lastname: Jenniskens
authors.affiliation: Department of Pathology, Radboud University Medical Center, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands.
authors.forename: H Ewout
authors.initials: HE
authors.lastname: Schaafsma
authors.affiliation: Department of Radiology, Radboud University Medical Center, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands.
authors.forename: Jelle O
authors.initials: JO
authors.lastname: Barentsz
authors.affiliation: Department of Urology, Radboud University Medical Center, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands.
authors.forename: J P Michiel
authors.initials: JPM
authors.lastname: Sedelaar
authors.affiliation: Department of Pathology, Radboud University Medical Center, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands.
authors.forename: Christina A
authors.initials: CA
authors.lastname: Hulsbergen-van de Kaa
authors.affiliation: Department of Urology, Radboud University Medical Center, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands.
authors.forename: J Alfred
authors.initials: JA
authors.lastname: Witjes
mesh_terms: D000368:Aged; D006801:Humans; D053685:Laser Therapy / Q000379:methods*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D011468:Prostatectomy / Q000379:methods*; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D025321:Surgery, Computer-Assisted
keywords: Focal therapy; Laser ablation; MRI; Prostate cancer