Transperineal Targeted Microwave Ablation (TMA) of localized prostate cancer guided by MRI-Ultrasound fusion and organ-based tracking: a pilot study.

backgroundTo investigate the efficacy of transperineal targeted microwave ablation (TMA) in treating localized prostate cancer (PCa).

methodsThis is a single-centre prospective phase 2 trial recruiting men with low to intermediate-risk localized PCa to undergo transperineal TMA. TMA was performed with MRI-Ultrasound fusion guidance and organ-based tracking. A per-protocol 6-month MRI and biopsy were performed for all patients. The primary outcome was any cancer detected on biopsy of each ablated area. Secondary outcomes included per-patient analysis of positive biopsy, complications, urinary symptom score, erectile function and quality of life (QOL) scores.

resultsIn the first 15 men, 23 areas were being treated. The median age was 70 years, number of TMA ablations were 5 (range 2-8), and the total ablation time and operating time was 22 (IQR 14-28) and 75 (IQR 65-85) minutes, respectively. PSA level dropped from a median of 7.7 to 2.4 ng/mL. For the primary outcome, 91.3% (21/23) ablated area had no cancer in 6-month biopsy. In per-patient analysis, 33.3% (5/15) had in or out-of-field positive biopsy at 6 months. Among these five cases, four of them were amenable to active surveillance and 1 (6.7%) case with out-of-field ISUP grade group 2 cancer received radiotherapy. The urinary symptoms, uroflowmetry, erectile function, and QOL scores had no significant difference at 6 months. One patient (out of five patients with normal erection) in the cohort complained of significant worsening of erectile function after TMA. Grade 1 complications including hematuria (33.3%), dysuria (6.7%), and perineal discomfort (13.4%) were observed.

conclusionsIn this first pilot study, transperineal TMA guided by MRI-Ultrasound fusion guidance and organ-based tracking was shown to be effective, safe, and easily applicable in men with localized PCa.