title: Real-Time MRI-Guided Focused Ultrasound for Focal Therapy of Locally Confined Low-Risk Prostate Cancer: Feasibility and Preliminary Outcomes.
abstract: OBJECTIVE
  Focal therapy is an emerging approach to the treatment of localized prostate cancer. The purpose of this study was to report the 6-month follow-up oncologic and functional data of the initial phase 1 trial of patients treated with focal transrectal MRI-guided focused ultrasound in North America.
  
  
  METHODS
  Four patients with a prostate-specific antigen (PSA) level of 10 ng/mL or less, tumor classification cT2a or less, and a Gleason score of 6 (3 + 3) were prospectively enrolled in the study and underwent multiparametric MRI and transrectal ultrasound-guided prostate systematic biopsy. Under MRI guidance and real-time monitoring with MR thermography, focused high-frequency ultrasound energy was delivered to ablate the target tissue. The incidence and severity of treatment-related adverse events were recorded along with responses to serial quality-of-life questionnaires for 6 months after treatment. Oncologic outcomes were evaluated with multiparametric MRI and repeat transrectal ultrasound-guided biopsy 6 months after treatment.
  
  
  RESULTS
  Four patients with a total of six target lesions were treated and had complications graded Clavien-Dindo I or less. Quality-of-life parameters were similar between baseline and 6-months. All four patients had normal MRI findings in the treated regions (100%), biopsy showed that three patients (75%) were clear of disease in the treated regions, representing complete ablation of five target lesions (83%). All patients had at least one Gleason 6-positive core outside of the treated zone.
  
  
  CONCLUSIONS
  MRI-guided focused ultrasound is a feasible method of noninvasively ablating low-risk prostate cancers with low morbidity. Further investigation and follow-up are warranted in a larger patient series with appropriate statistical analysis of oncologic and functional outcome measures.
authors.affiliation: 1 Department of Medical Imaging, University Health Network, Mount Sinai Hospital, Women's College Hospital, University of Toronto, Toronto General Hospital, 585 University Ave, Toronto ON M5G 2N2, Canada.
authors.forename: Sangeet
authors.initials: S
authors.lastname: Ghai
authors.affiliation: 2 Department of Surgical Oncology, Division of Urology, University Health Network, University of Toronto, Toronto ON, Canada.
authors.forename: Alyssa S
authors.initials: AS
authors.lastname: Louis
authors.affiliation: 1 Department of Medical Imaging, University Health Network, Mount Sinai Hospital, Women's College Hospital, University of Toronto, Toronto General Hospital, 585 University Ave, Toronto ON M5G 2N2, Canada.
authors.forename: Meghan
authors.initials: M
authors.lastname: Van Vliet
authors.affiliation: 2 Department of Surgical Oncology, Division of Urology, University Health Network, University of Toronto, Toronto ON, Canada.
authors.forename: Uri
authors.initials: U
authors.lastname: Lindner
authors.affiliation: 1 Department of Medical Imaging, University Health Network, Mount Sinai Hospital, Women's College Hospital, University of Toronto, Toronto General Hospital, 585 University Ave, Toronto ON M5G 2N2, Canada.
authors.forename: Masoom A
authors.initials: MA
authors.lastname: Haider
authors.affiliation: 1 Department of Medical Imaging, University Health Network, Mount Sinai Hospital, Women's College Hospital, University of Toronto, Toronto General Hospital, 585 University Ave, Toronto ON M5G 2N2, Canada.
authors.forename: Eugen
authors.initials: E
authors.lastname: Hlasny
authors.affiliation: 1 Department of Medical Imaging, University Health Network, Mount Sinai Hospital, Women's College Hospital, University of Toronto, Toronto General Hospital, 585 University Ave, Toronto ON M5G 2N2, Canada.
authors.forename: Paula
authors.initials: P
authors.lastname: Spensieri
authors.affiliation: 3 Department of Pathology and Laboratory Medicine, University Health Network, University of Toronto, Toronto ON, Canada.
authors.forename: Theodorus H
authors.initials: TH
authors.lastname: Van Der Kwast
authors.affiliation: 4 Department of Anesthesia and Pain Management, University Health Network, University of Toronto, Toronto, ON, Canada.
authors.forename: Stuart A
authors.initials: SA
authors.lastname: McCluskey
authors.affiliation: 1 Department of Medical Imaging, University Health Network, Mount Sinai Hospital, Women's College Hospital, University of Toronto, Toronto General Hospital, 585 University Ave, Toronto ON M5G 2N2, Canada.
authors.forename: Walter
authors.initials: W
authors.lastname: Kucharczyk
authors.affiliation: 2 Department of Surgical Oncology, Division of Urology, University Health Network, University of Toronto, Toronto ON, Canada.
authors.forename: John
authors.initials: J
authors.lastname: Trachtenberg
mesh_terms: D000368:Aged; D014408:Biomarkers, Tumor / Q000097:blood; D006801:Humans; D061705:Image-Guided Biopsy; D053783:Magnetic Resonance Imaging, Interventional; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D011446:Prospective Studies; D017430:Prostate-Specific Antigen / Q000097:blood; D011471:Prostatic Neoplasms / Q000473:pathology / Q000601:surgery*; D011788:Quality of Life; D011795:Surveys and Questionnaires; D016896:Treatment Outcome; D059708:Ultrasonic Surgical Procedures; D018084:Ultrasonography, Interventional
chemical_list: D014408:Biomarkers, Tumor; D017430:Prostate-Specific Antigen
keywords: MRI-guided high-intensity focused ultrasound; focal therapy; prostate cancer