Focal irreversible electroporation for the treatment of localised prostate cancer: a systematic review.

Background: Focal irreversible electroporation (IRE) has shown promising initial oncological and functional outcomes in the treatment of localised prostate cancer (PCa), although robust evidence to support its efficacy and optimal utilisation is still maturing. We aim to summarise the oncological outcomes, functional outcomes, and safety profile of IRE for the treatment of localised PCa. Methods: A search was performed across four electronic databases: MEDLINE, Embase, Web of Science, and Cochrane Database of Systematic Reviews; 620 articles were screened after removal of duplicates; 73 full-texts were reviewed. Results: Thirty-one articles representing 29 studies were included. Focal IRE patients ranged from 10 to 411 patients. Median follow-up ranged from 6 to 60 months. Three studies reported exclusively on salvage-IRE, and three reported on both primary- and salvage-IRE. A combination of all risk-groups was included. Safety margins ranged from 0 to 10 mm. Early post-IRE imaging within 1 month of treatment was performed in 14 studies. Post-treatment biopsy was performed in 23 studies, ranging from 6 to 18 months after IRE. In-field recurrence rates ranged from 0-33% and 0-10% in the primary and salvage settings respectively. Out-of-field recurrence rates ranged from 0-33% and 0-14% respectively. Retreatment rates ranged from 0-37% in the primary setting and 0-24% in the salvage setting. In the primary setting, four studies reported a decrease in pad-free rates, ranging from 1-2%, while six of twelve studies noted improvements in urinary patient-reported outcome measures (PROMs). Baseline erections sufficient for intercourse declined in 10 studies, ranging from 3-22%, and deterioration in sexual function PROMs was reported in eight of 13 studies. In the salvage setting, pad-free rates decreased by 4-33% across three studies, and potency rates declined by 14-22% in four studies. Clavien-Dindo III events occurred in 1-19% of patients across six studies, and two cases of rectourethral fistula were reported. Conclusions: Oncological outcomes, although still maturing, appear promising. Functional outcomes compare favourably against whole-gland treatment, particularly in the primary treatment setting. Focal IRE appears to have a role in salvage treatment. Comparative studies are needed to evaluate its role amongst the growing array of treatments for localised PCa.