This section describes efficacy outcomes from the published literature that the committee considered as part of the evidence about this procedure. For more detailed information on the evidence, see the interventional procedure overview.
4.1 In a case series of 25 patients treated by irreversible electroporation for prostate cancer, the ablated zone was histologically clear of disease in all of the men who had a 7‑month follow-up biopsy (84% [21/25] of patients). Overall, 76% (16/21) of men were histologically clear of significant disease and 38% (8/21) of men were histologically clear of any cancer at all. One patient had a significant finding in the field outside the adjacent zone; the lesion had not been detected preoperatively or on his 6‑month MRI. Of the 5 patients with significant disease on follow-up biopsy, 3 remain on active surveillance, 1 is awaiting repeat irreversible electroporation and 1 had a radical prostatectomy.
4.2 In a case series of 34 patients, suspicious residual disease was seen on multiparametric MRI in 18% (6/34) of patients during follow-up. In 2 of these patients, prostate-specific antigen (PSA) levels dropped significantly from baseline and they remain on surveillance. The other 4 patients had secondary treatment (1 irreversible electroporation, 2 high‑intensity focused ultrasound, 1 radical prostatectomy). Only 1 patient had histological verification of treatment failure by transperineal targeted biopsy. In a second case series of 25 patients, 28% (7/25) of men had a template biopsy that was positive for prostate cancer at 6‑month follow-up. Primary failure was reported in 16% (4/25) of patients: 3 patients subsequently had surgery.
4.3 In the first case series of 25 patients there were no statistically significant changes in urinary symptom score, urinary function score, sexual function score, bowel function score, SF-12 physical component score or SF-12 mental component score at 6‑month follow-up (n=18). Pad-free continence rates were 100%, 94%, 94% and 100% and leak-free continence rates were 67%, 53%, 65% and 67% at baseline, 6‑week, 3‑month and 6‑month follow-up respectively. The proportion of men with erections sufficient for penetration were 44%, 38%, 47% and 56% at baseline, 6‑week, 3‑month and 6‑month follow-up respectively. In the case series of 34 patients, potency was preserved in 95% (19/20) of men who were potent before treatment. All men who were continent before treatment were still continent afterwards (24/24). In the second case series of 25 patients, 77% (17/22), 81% (13/16) and 88% (15/17) of patients had normal urinary function at baseline, 6‑month and 12‑month follow-up respectively. Of the 17 patients with normal urinary function at baseline, 2 reported a decrease in score to below normal at 6‑month and 1 at 12‑month follow-up. At 12‑month follow-up, 1 patient with normal erectile function at baseline reported new difficulty with potency. Use of incontinence pads was reported in 1 and 2 men at 6‑month and 12‑month follow-up respectively.
4.4 In a case series of 16 patients, statistically significant differences were seen in 1 domain in the Expanded Prostate Cancer Index Composite (EPIC) questionnaire: quality of life concerning urinary function decreased (p=0.01) at 1‑week and 4‑week follow-up. Quality of life concerning sexual function, hormonal function and bowel habits did not significantly decrease during follow-up.
4.5 The specialist advisers listed cancer control and cancer-related survival as the key efficacy outcomes.