FOCAL THERAPY WITH HIGH-INTENSITY FOCUSED ULTRASOUND FOR THE LOCALIZED PROSTATE CANCER BASED ON THE LOCALIZATION WITH MRI-TRUS FUSION IMAGE-GUIDED BIOPSY: 1-YEAR PROSPECTIVE STUDY

: (Objective) To evaluate the efficacy and invasiveness of focal therapy with transrectal high-intensity focused ultrasound (HIFU) for localized prostate cancer based on spatial location of significant cancer with magnetic resonance imaging (MRI)-transrectal ultrasound (TRUS) fusion image-guided biopsy. (Methods) Patients with low- and intermediate-risk significant prostate cancer who were followed-up at least 1 year, were prospectively recruited. The spatial localization of the significant cancer was determined by MRI-TRUS fusion image-guided transperineal prostate biopsy. Focal therapy targeting the regions of significant cancer was performed by transrectal HIFU using a Sonablate® 500 (SonaCare Medical, Indianapolis, IN, USA). Serum prostate-specific antigen (PSA) kinetics, multi-parametric MRI, and MRI-TRUS fusion image-guided prostate biopsy were analyzed to determine the treatment efficacy. Questionnaires and uroflowmetry were performed to evaluate the invasiveness. (Results) Ten men with median age of 67 years (range, 48-79), median PSA level of 7.07 ng/ml (range, 4.67-15.99), median prostate volume of 25 ml (range, 19-36) were treated. Median operative time was 29.5 minutes (range, 14-85). Catheterization was performed within 24 hours after the treatment in all patients. The median PSA concentration significantly decreased to 1.35 ng/ml (p<0.0001) at 3 months after the treatment. Contrast-enhanced T1-weighted MRI showed the disappearance of blood flow in all targeted regions of the prostate. MRI-TRUS fusion image-guided prostate biopsy detected the significant cancer out of the treated region in 1 patient. In urinary function, residual urine was significantly increased at 3 months after the treatment (p=0.007), but improved to the preoperative level (p=0.411). There was no significant deterioration in IPSS, IPSS QOL, OABSS, and the urinary function domain of EPIC between before and 3, 6, 9, and 12 months after the treatment. In sexual function, there was no significant difference in IIEF-5 and the sexual domain of EPIC between before and 3, 6, 9, and 12 months after the treatment. In quality of life, there was no significant difference in EPIC and SF-36 between before and 3, 6, 9, and 12 months after the treatment. The proportion of men with erections sufficient for penetration and ejaculation remained unchanged at 100% (5 of 5 patients). No serious adverse events were recorded. (Conclusions) The focal therapy with HIFU has the potential to provide accurate treatment with low morbidity in patients with localized prostate cancer. Further large studies are required to investigate the effects of the focal therapy with HIFU for analysis of oncological and functional outcomes in patients with localized prostate cancer.