Irreversible Electroporation (IRE) has been used for
prostate cancer since 2011. There have been clinical trials as
well as anecdotal approaches [1]. Trials require a long time and
need to compare many treatment types. Randomized multi-center
approaches are needed. The outcome collected up to now showed
hopeful results. Prospective clinical trials are required. IRE for
prostate cancer should attain the stage of being recommended
by international guidelines. The IRE machine (The NanoKnife)
is based on direct current generator and needle electrodes [2,3]
. With TRUS guidance, the electrodes are placed perineally. The
probes should be placed away from the urethra, the rectum, and the
sphincter to avoid damage. General anesthesia in supine position
is the regime. The procedure takes about 45-90 min. A catheter is
inserted for 24 hours.

Irreversible electroporation uses high-voltage electric pulses
that cause cell death. These pulses travel between two or more
electrodes, causing a leak in the cell membrane, formed by the
creation of nanopores. Depending on the field amplitude, duration
and number of electrical pulses, this process can be temporary
(reversible electroporation) or permanent IRE. In the case of
permanent, due to changes to the membrane, the cell will become
incapable of holding on to its homeostasis and will apoptose.

Ting et al. evaluated functional and oncological outcomes
in 25 patients following IRE. No significant changes in urinary,
sexual or bowel function were noted (using AUA scores). At
follow-up 5 patients (21%) had suspicious lesions on mpMRI, of
which four (19%) proved to be significant on biopsy. All patients
were leak-free continent and erectile function was reported to be
stable. Valerio et al. reported on 34 patients undergoing IRE for
organ-confined prostate cancer (ranging from low- to high risk
disease). After a median follow-up of 6 months for 24 patients
100% of patients were continent and potency was preserved in
95% (19/20) men. Van den Bos et al. prospectively reported on
63 patients who received IRE with a minimum follow-up of 6
months. The results demonstrated no change in quality of life or
mental, physical, bowel or urinary functions. A slight decrease in
sexual quality of life was observed [4].

Thermal ablation methods have limitations due to the vessel
heat sink effect. This protects cancer nearby vessels resulting in
high recurrence rates. Quite the opposite, pathology demonstrated
that IRE lesions, showed complete destruction of tissue up to
the vessel wall without vessel destruction. This in the prostate,
preserves blood flow to maintain potency [5].

Results from one of the largest IRE studies was recently
published by van den Bos et al in which 63 patients with Gleason
6-7 disease were treated with IRE. Sixteen percent of patients
had an in-treatment field recurrence and 24% were found to
have persistent cancer anywhere within the prostate. No highgrade
adverse events occurred and physical, mental, bowel, and
urinary quality of life measures remained unchanged at 6 months
postoperatively. Despite the theoretical claim that IRE might be
less damaging to nerve tissue, mild declines in sexual quality of
life median score from 66 to 54 at 6 months (P

Guenther et al presented 471 tissue ablation procedures in
429 patients with PCa using IRE (NanoKnife, AngioDynamics
Inc., USA). Seventy patients had had PCa related treatments prior
to IRE: Sixteen patients had undergone Radical Prostatectomy
(RPE), twenty-three had had Radiation Therapy (RT), 5 had had
both. Seventeen patients had undergone a Transurethral Resection
Of The Prostate (TURP), 8 had been treated with High-Intensity
Focused Ultrasound (HIFU), two of which had had the procedure
performed twice. The majority (N = 29) of those with previous
treatments had undergone Androgen Deprivation Therapy (ADT).
The retrospective study concludes that Irreversible Electroporation
(IRE) is a safe, effective and suitable modality for the treatment
of PCa at all clinical stages and recurrent disease. Continence
was preserved in all cases. The comparison of IRE with Radical
Prostatectomy (RPE) revealed similar recurrence rates over time,
indicating similar effectiveness of IRE to RPE. Thus the data
illustrates the feasibility of IRE for PCa treatments. However, data
needs to be confirmed by more systematic studies [7].

Federico Collettini reported after a median follow-up of 20
months, focal irreversible electroporation of localized prostate
cancer was associated, with low urogenital toxicity and promising
oncologic outcomes [8].

Since Shoulong Dong described the first trial conducted
in humans involving administration of High Frequency bipolar
pulses therapy for prostate cancer, it was clear that bipolar pulse is
a minimally invasive nonthermal therapy in tumor ablation that can
reduce the dose of muscle relaxant during treatment. Compared
to radical prostatectomy and thermal therapy, it can preserve
the neurovascular bandle, urethra, and major vasculature in the
prostate, which is beneficial to patient recovery. The postoperative
effect of such a treatment on patients was very encouraging, that
is, sexual function was preserved in 14 (100%) of 14 patients, 40
(100%) of 40 patients could control urination and did not require
urinal pads, and 0 of 40 patients had urinary incontinence during
surgery. The clinical trials were conducted successfully, and they
provided valuable insights regarding the treatment of prostate
cancer using high frequency bipolar pulses, which will promote the
ablation of solid tumors by IRE [9]. The clinical results collected
so far has shown encouraging results and uniformly state IRE as
a safe and effective treatment (at least for focal ablation) but all
merit further studies.

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