Magnetic resonance guided focused high frequency ultrasound ablation for focal therapy in prostate cancer – phase 1 trial
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To evaluate the feasibility and safety of focal therapy for low–intermediate risk prostate cancer (PCa) with magnetic resonance-guided high frequency focused ultrasound (MRgFUS)
This IRB-approved phase 1 prospective study enrolled eight patients with prostate specific antigen (PSA) ≤ 10 ng/ml, ≤ cT2a and Gleason score ≤ 7 (4 + 3) disease following informed consent. Under MRI guidance, focused high frequency ultrasound energy was delivered to ablate the target tissue. Treatment-related adverse events were recorded. Oncologic outcomes were evaluated with multiparametric MRI, PSA and TRUS biopsy at 6 months following treatment.
Ten target lesions [six Gleason 6 lesions, two Gleason 7 (3 + 4) and two Gleason 7 (4 + 3)] were treated in eight men (prostate volume range, 25–50 cc; mean MRI time, 248 min per patient; mean sonication duration, 65 min). Mean target volume was 2.7 cc and mean post-treatment non-perfused volume was 4.3 cc. Quality of life parameters were similar between baseline and 6 months in 6/8 patients. All treated regions were negative on MRI; 4/8 patients and 6/10 target lesions (60%) were clear of disease on biopsy. One patient with 2-mm Gleason 8 disease in one of five cores from treatment site (4 + 3 disease at baseline) subsequently underwent prostatectomy with negative surgical margins. Three patients with low volume (5–15%) Gleason 6 residual disease were offered active surveillance. Mean PSA decreased from 5.06 at baseline to 3.4 ng/ml at 6 months.
MRgFUS is a feasible and safe method of noninvasively ablating low–intermediate risk PCa with acceptable short-term oncologic outcomes.
• Focal therapy selectively ablates locally confined, clinically significant index lesion with a margin while sparing rest of gland and adjacent vital structures.
• Magnetic resonance-guided focused high frequency ultrasound surgery (MRgFUS) combines MRI with HIFU.
• MRgFUS provides ability to monitor treatments in real time and allows a targeted approach for focal ablation.
• MRgFUS is a feasible, safe method of noninvasively ablating low–intermediate risk PCa.
• MRgFUS provides acceptable oncologic outcomes at 6 months.
KeywordsProstate cancer Magnetic resonance imaging High-intensity focused ultrasound ablation Interventional magnetic resonance imaging Image-guided surgery
High intensity focused ultrasound
Health-Related Quality of Life
International Consultation on Incontinence Questionnaire Short Form
International Index of Erectile Function
International Prostate Symptom Score
Multiparamteric magnetic resonance imaging
Magnetic resonance-guided high frequency Focused ultrasound surgery
This study has received funding by InSightec Ltd., the Ontario Research fund (ORF) and the Canadian Foundation for Innovation (CFI).
Compliance with ethical standards
The scientific guarantor of this publication is Sangeet Ghai.
Conflict of interest
The authors of this manuscript declare no relationships with any companies whose products or services may be related to the subject matter of the article.
Statistics and biometry
No complex statistical methods were necessary for this paper.
Written informed consent was obtained from all subjects (patients) in this study.
Institutional review board approval was obtained.
Study subjects or cohorts overlap
The first four study subjects or cohorts (all with Gleason 6 disease) were previously reported in American Journal of Roentgenology (2015 Aug;205(2):W177-84). The first of these four patients was also reported without any follow up-in the Canadian Urological Association Journal (2012 Dec;6(6):E283-6).
• performed at one institution