MP46-06 FOCAL ABLATION VERSUS RADICAL PROSTATECTOMY FOR INTERMEDIATE-RISK PROSTATE CANCER: INTERIM ANALYSIS OF A RANDOMIZED CONTROLLED TRIAL

Abstract

INTRODUCTION AND OBJECTIVE: To compare oncological and functional outcomes after one year, between focal prostate ablation (FA) using High Intensity Focused Ultrasound (HIFU) and radical prostatectomy (RP), in patients with intermediate risk prostate cancer (PCa). METHODS: Patients presenting with unilateral PCa (cT<3, ISUP<4 and PSA<20 ng/ml) between December 2017 and February 2020 were randomized 1:1 to treatment with HIFU or RP. The median (IQR) age was 63 years (60-69), PSA was 7.1 ng/mL (5-10), MRI tumor diameter was 13 mm (10-17), and the prostate volume was 37 mL (27- 47). FA was performed using a FocalOne® HIFU device. Robotic RP was performed at high volume centers using unilateral nerve-sparing surgery. Treatment failure (TF) in the FA arm was defined as ISUP>3 in MRI-targeted and/or systematic prostate biopsies (bx) 12 months post treatment and/or the need for whole gland treatment. TF in the RP arm was defined as PSA>0.2ng/mL and/or a positive surgical margin (PSM). Voiding and erectile function was assessed using patient reported IPSS and IIEF-5 questionnaires. De novo urinary incontinence (UI) was defined as the patient reported need for 1 or more pads per day. RESULTS: 118 patients were randomized to FA (56) and RP (62). The cross over rate was 20% (24/118) and 2 patients declined any treatment. 66% (76/116) were treated by FA and 34% (40/116) by RP and included for per-protocol analysis. 97% (74/76) of the FA group underwent MRI and prostate bx after one year. The remaining 2 had negative MRI and declined bx. TF after FA and RP occurred in 5% (4/76, 95% CI: 1-13) and 17% (7/40, 95% CI: 7-36), respectively, p=0.022. In the FA group, salvage radiation (SR) treatment was performed in 3 patients, while 1 was treated with salvage RP. 2 patients required repeat FA due to detected ISUP 3 PCa in untreated prostate zones. In the RP group, 6 patients had PSM and 1 developed pelvic lymph node metastases. 97% (74/76) of the FA group underwent MRI and prostate bx after one year. The remaining 2 had negative MRI and declined bx. TF after FA and RP occurred in 5% (4/76, 95% CI: 1-13) and 17% (7/40, 95% CI: 7-36), respectively, p=0.022. In the FA group, salvage radiation (SR) treatment was performed in 3 patients, while 1 was treated with salvage RP. 2 patients required repeat FA due to detected ISUP 3 PCa in untreated prostate zones. In the RP group, 6 patients had PSM and 1 developed pelvic lymph node metastases. Median (IQR) baseline IPSS for FA and RP was 9 (5-12) and 7 (4-18), p=0.8. After one year 5 (3-11) and 7 (4-14), p=0.2. Median (IQR) baseline IEEF-5 for FA and RP was 22 (12-25) and 23 (15-24), p=0.8. After one year 18 (10-23) and 5 (5-6), p<0.001. De novo UI occurred in 4% (3/76, 95% CI: 1-12) following FA and in 35% (14/40, 95% CI: 19-59) following RP, p<0.001. CONCLUSIONS: One year post treatment, FA achieved good oncological efficacy and preserved erectile function and continence better than RP. The incidence of crossover in the RP group was high, demonstrating patient preference for a less invasive treatment option.