Targeted Ablation Using Ultrasound-Guided Irreversible Electroporation of Index Tumors (TARGET Study): Prospective Development Study Evaluating Safety, Patient-Reported Outcomes, and Oncologic Efficacy

INTRODUCTION: We studied patient-reported functional outcomes, safety, and oncologic efficacy of focal irreversible electroporation as a primary treatment for intermediate-risk prostate cancer.

METHODS: Between February 2015 and April 2017, 20 consecutive patients elected irreversible electroporation and underwent 22 treatments. All underwent MRI-targeted and systematic transrectal biopsies. Eligibility criteria were grade group 2/3 prostate cancer in a maximum of 2 adjacent sextant prostate sectors in 1 hemigland without extraprostatic extension on MRI. Ablation was performed with a 5-mm cancer margin. Any grade group 1 cancer outside mapped index lesion was untreated. Outcome measures were based on the Prostate Quality of Life Survey, Male Sexual Health Questionnaire, and MRI-targeted and systematic biopsies at 3 and 12 months.

RESULTS: Nineteen patients completed irreversible electroporation. One had electrocardiographic changes, and irreversible electroporation was aborted. No deterioration was detected in urinary or sexual domains (-0.2, 95% CI -1.4, 0.9, P = .7, and -1.9, 95% CI -10.1, 6.4, P = .6, respectively) or health-related quality of life (-0.2, 95% CI -1.4, 1.0, P = .7) at 6 months post ablation. Ejaculation volume decreased at 12 months (-1.5 points, 95% CI -2.4, -0.5, P = .003). At 12 months of follow-up, 14/19 patients (74%, 95% CI 49%, 91%) had no clinically significant cancer anywhere in the prostate. Radical treatment-free survival was 79% at 2 years (95% CI 53%, 92%) and 73% at 4 years (95% CI 47%, 88%).

CONCLUSIONS: Our data show promising oncologic and functional outcomes following focal irreversible electroporation treatment for carefully selected patients with intermediate-risk prostate cancer. Further research should compare irreversible electroporation with active surveillance.