Irreversible Electroporation for Prostate Tissue Ablation in Patients with Intermediate-risk Prostate Cancer: Results from the PRESERVE Trial

Background and objective The PRESERVE study (NCT04972097) assessed the safety and effectiveness of irreversible electroporation (IRE) with the NanoKnife System to ablate prostate tissue in patients with intermediate-risk prostate cancer (PCa). Methods This prospective, nonrandomized, single-arm pivotal trial included patients in the USA who met the key inclusion criteria: age >50 yr with organ-confined, grade group 2 or 3 PCa, clinical stage ≤T2c, prostate-specific antigen (PSA) ≤15 ng/ml, or PSA density <0.15 ng/ml². The primary endpoints were the rate of local pathological complete response (negative in-field biopsy) and the incidence, type, and severity of adverse events by 12 mo. The secondary endpoints included PSA kinetics, changes in prostate volume, retreatment, and urinary/sexual function. Key findings and limitations Of the 121 patients treated with IRE, the negative in-field biopsy rate at 12 mo was 71% (95% confidence interval [CI]: 62%, 79%). The secondary endpoint of negative in-field biopsy rate defined by the Delphi consensus criterion was 84% (95% CI: 76%, 90%). The time to median PSA nadir was 3.5 mo, and the median percent reduction in PSA at 6 mo was 68.2%. Urinary function outcomes had a mean change from baseline to 12 mo of 3 in the University of California Los Angeles Expanded Prostate Cancer Index Composite urinary domain total score and a mean change of –2 in the International Prostate Symptom Score total symptom score. At 12 mo, 84% of patients with good baseline sexual function maintained erections sufficient for penetration. Fourteen (12%) patients experienced Common Terminology Criteria for Adverse Events grade ≥3 and three experienced procedure-related grade 3 adverse events. Conclusions and clinical implications IRE with the NanoKnife System is safe and effective for prostate tissue ablation.