Salvage irreversible electroporation for radio‐recurrent prostate cancer – the prospective FIRE trial

Abstract Objectives To prospectively assess the safety, functional‐ and oncological‐outcomes of irreversible electroporation (IRE) as salvage therapy for radio‐recurrent focal prostate cancer in a multicenter setting. Patients and methods Men with focal recurrent PCa after external beam radiation or brachytherapy without metastatic disease on staging imaging and co‐registration between mpMRI and biopsies were prospectively included in this multicenter trial. Adverse events were reported following the Clavien‐Dindo classification. Validated questionnaires were used for patient‐reported functional outcomes. Follow‐up consisted of 3 monthly prostate specific antigen (PSA) levels, a 6‐month mpMRI and standardised transperineal template mapping biopsies at 12‐months. Thereafter follow‐up was guided by MRI and/or PSMA‐PET/CT and PSA. Local recurrence was defined as any ISUP score ≥2 on biopsies. Results 37 patients were analysed with a median (interquartile range (IQR)) follow up of 29 (22–43) months. Median age was 71 (53–83), median PSA was 3.5 ng/mL (2.7–6.1). 28 (75.5%) patients harboured intermediate risk and 9 patients (24.5%) high risk PCa. Seven patients (19%) reported self‐limiting urgency, frequency, or hematuria (grade 1–2). Seven patients (19%) developed a grade 3 AE; urethral sludge requiring transurethral resection. At 12 months post treatment 93% of patients remained continent and erectile function sufficient for intercourse deteriorated from 35% to 15% (4/27). Local control was achieved in 29 patients (78%) and 27 patients (73%) were clear of local and systemic disease. Four (11%) patients had local recurrence only. Six (16%) patients developed metastatic disease with a median time to metastasis of 8 months. Conclusion The FIRE trial shows that salvage IRE after failed radiation therapy for localised PCa is safe with minimal toxicity, and promising functional and oncological outcomes. Salvage IRE can offer a possible solution for notoriously difficult to manage radio recurrent prostate tumours.