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/ml. 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.