Real-Time MRI-Guided Focused Ultrasound for Focal Therapy of Locally Confined Low-Risk Prostate Cancer: Feasibility and Preliminary Outcomes

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.

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.

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.

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.

AJR Am J Roentgenol. 2015 Aug;205(2):W177-W184.

Ghai S1, Louis AS2, Van Vliet M1, Lindner U2, Haider MA1, Hlasny E1, Spensieri P1, Van Der Kwast TH3, McCluskey SA4, Kucharczyk W1, Trachtenberg J2.

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.
2 Department of Surgical Oncology, Division of Urology, University Health Network, University of Toronto, Toronto ON, Canada.
3 Department of Pathology and Laboratory Medicine, University Health Network, University of Toronto, Toronto ON, Canada.
4 Department of Anesthesia and Pain Management, University Health Network, University of Toronto, Toronto, ON, Canada.