Irreversible Electroporation for Prostate Cancer

Radiation therapy and IRreversible electroporation for intermediate risk prostate cancer (RTIRE)

INTRODUCTION

Radiation Therapy and IRreversible Electroporation for Intermediate Risk Prostate Cancer (RTIRE) is a phase II clinical trial testing combination of radiation therapy and irreversible electroporation for intermediate risk prostate cancer BACKGROUND: PCa is the most common non-cutaneous cancer in men and the second leading cause of cancer death in men. PCa treatment is associated with long term side effects including urinary, sexual, and bowel dysfunction. Management of PCa is based on risk stratification to prevent its overtreatment and associated treatment-related toxicity. There is increasing interest in novel treatment strategies, such as focal therapy, to minimize treatment associated morbidity. Focal therapy alone has yet to be included in mainstream guidelines, given ongoing concerns with potentially higher risk of recurrence. We hypothesize combining focal therapy with whole gland, reduced dose radiotherapy will provide acceptable oncologic efficacy with minimal treatment associated morbidity. RTIRE is a phase II single institution, investigator-initiated study combining a local ablative technique though local irreversible electroporation (IRE) with MR guided RT (MRgRT) to treat the entire prostate. The goal is to provide excellent oncologic outcomes and minimize treatment related side effects through leveraging benefits of locally ablative therapy with established radiation treatment techniques.

METHODS

A total of 42 men with intermediate risk PCa per NCCN guidelines and focal grade group (GG) 2 or 3, Gleason Score (GS) 3 + 4 or GS 4 + 3, cancer in an MRI target will be enrolled. Patients with MRI visible foci of GG2/GG3 will undergo focal therapy with IRE of this lesion. Following successful focal therapy, patients will then undergo a course of reduced dose, whole gland MRgRT with either 32.5 Gy in 5 Fractions or 22 Gy in 2 fractions. The primary objective of the study is to determine safety. Secondary outcomes include evaluation of oncologic efficacy (as measured by the proportion of patients free of clinically significant cancer as defined as > Grade Group 1 at 1-year follow-up biopsy), imaging characteristics of patients pre and post RTIRE, impact on quality of life (QoL), and PSA kinetics.

DISCUSSION

Combining IRE with a reduced dose radiotherapy may offer a new treatment paradigm for PCa by both reducing treatment effects of full dose radiotherapy and minimizing the risk of recurrence observed with focal therapy.

TRIAL REGISTRATION

Clinicaltrials.gov identifier: NCT05345444. Date of registration: April 25, 2022.

PROTOCOL VERSION

6.0, July 7, 2023.

A Description and Safety Overview of Irreversible Electroporation for Prostate Tissue Ablation in Intermediate-Risk Prostate Cancer Patients: Preliminary Results from the PRESERVE Trial

The PRESERVE study (NCT04972097) aims to evaluate the safety and effectiveness of the NanoKnife System to ablate prostate tissue in patients with intermediate-risk prostate cancer (PCa). The NanoKnife uses irreversible electroporation (IRE) to deliver high-voltage electrical pulses to change the permeability of cell membranes, leading to cell death. A total of 121 subjects with organ-confined PCa ≤ T2c, prostate-specific antigens (PSAs) ≤ 15 ng/mL, and a Gleason score of 3 + 4 or 4 + 3 underwent focal ablation of the index lesion. The primary endpoints included negative in-field biopsy and adverse event incidence, type, and severity through 12 months. At the time of analysis, the trial had completed accrual with preliminary follow-up available. Demographics, disease characteristics, procedural details, PSA responses, and adverse events (AEs) are presented. The median (IQR) age at screening was 67.0 (61.0-72.0) years and Gleason distribution 3 + 4 (80.2%) and 4 + 3 (19.8%). At 6 months, all patients with available data (n = 74) experienced a median (IQR) percent reduction in PSA of 67.6% (52.3-82.2%). Only ten subjects (8.3%) experienced a Grade 3 adverse event; five were procedure-related. No Grade ≥ 4 AEs were reported. This study supports prior findings that IRE prostate ablation with the NanoKnife System can be performed safely. Final results are required to fully assess oncological, functional, and safety outcomes.

Irreversible electroporation as a focal therapy for localized prostate cancer: A systematic review

Introduction

Irreversible electroporation (IRE) is a new and promising focal therapy for the treatment of localized prostate cancer. In this systematic review, we summarize the literature on IRE for prostate cancer published over the last decade.

Methods

PubMed and EMBASE were searched with the end date of May 2023 to find relevant publications on prostate cancer ablation using IRE. Original studies with focal IRE as the primary curative treatment which reported on functional or oncological outcomes were included. The bibliography of relevant studies was also scanned to identify suitable articles.

Results

A total of 14 studies reporting on 899 patients treated with IRE for localized prostate cancer were included. Of all the studies reviewed, 77% reported on recurrence within the zone of ablation, and it ranged from 0% to 38.9% for in-field and 3.6% to 28% for out-of-field recurrence. Although, a standardised follow-up protocol was not followed, all the studies employed serial prostate-specific antigen monitoring, a multiparametric magnetic resonance imaging, and a biopsy (6-12 months post-treatment). Across all the studies, 58% reported that the urinary continence returned to the pretreatment levels and 25% reported a minor decrease in the continence from the baseline at 12-months of follow-up. Erections sufficient for intercourse varied from 44% to 75% at the baseline to 55% to 100% at 12-months of follow-up across all the studies.

Conclusion

IRE, as a focal therapy, shows promising results with minimal complications and reasonably effective oncological control, but the data comparing it to the standard of care is still lacking. Future research should focus on randomized definitive comparisons between IRE, radical prostatectomy, and radiation therapy.

Irreversible electroporation: Beyond the limits of tumor ablation

Irreversible Electroporation (IRE) is a non-thermal tumor ablation technique. High-voltage electrical pulses are applied between pairs of electrodes inserted around and/or inside a tumor. The generated electric current induces the creation of nanopores in the cell membrane, triggering apoptosis. As a result, IRE can be safely used in areas near delicate vascular structures where other thermal ablation methods are contraindicated. Currently, IRE has demonstrated to be a successful ablation technique for pancreatic, renal, and liver tumors and is widely used as a focal therapeutic option for prostate cancer. The need for specific anesthetic management and accurate parallel placement of multiple electrodes entails a high level of complexity and great expertise from the interventional team is required. Nevertheless, IRE is a very promising technique with a remarkable systemic immunological capability and may impact on distant metastases (abscopal effect).

One-year Follow-up Results of Transperineal Biopsy For Patients Undergoing Irreversible Electroporation Treatment in Localized Prostate Cancer

OBJECTIVE

This article reports on the early results of a 1-year follow-up study investigating the efficacy of irreversible electroporation in the treatment of localized prostate cancer.

METHODS

The study included 18 out of 40 patients diagnosed with low- and intermediate-risk prostate cancer who underwent irreversible electroporation. Treatment results were evaluated through confirmation biopsies, comparing prostate-specific antigen levels, international prostate symptom scoring, and international index of erectile dysfunction scores before irreversible electroporation and at the 12-month mark.

RESULTS

The mean age of the patients was 61.1 years (SD ±6.5). Out of the 18 patients, 16 were tumor free (88.8%), while 2 experienced recurrences, one within the treatment field and the other outside of it (P < .001). Irreversible electroporation significantly reduced mean prostate-specific antigen levels (6.73 ng/mL vs. 2.05 ng/mL, P < .001), indicating a 69.5% reduction within 12 months. Furthermore, there was a significant improvement in mean international prostate symptom scores at the 12-month followup (10.05 vs. 7.52, P=.003). The mean international index of erectile dysfunction scores before treatment was 19.17 (SD ±5.85), and after irreversible electroporation, it was 18.67 (SD ±6.34), with no statistically significant change (P=.065).

CONCLUSION

The short-term oncological results of irreversible electroporation treatment are promising, particularly for patients in the low- and intermediate-risk groups. Additionally, irreversible electroporation does not negatively impact the international index of erectile dysfunction; however, it may lead to a decrease in international prostate symptom scores.

Sudden Occurrence of Pacemaker Capture Failure during Irreversible Electroporation Ablation for Prostate Cancer in Post-COVID-19 Patient: A Case Report

Irreversible electroporation (IRE) ablation is a novel treatment option for localized prostate cancer. Here, we present a case of an abrupt and fatal arrhythmia during the IRE procedure in a prostate cancer patient with an implanted permanent pacemaker. A 78-year-old male patient with a pacemaker due to sick sinus syndrome and syncope was scheduled for IRE prostate ablation surgery under general anesthesia. He had a history of recovering from coronavirus disease 2019 (COVID-19) after having been vaccinated against it and recovered without sequalae. Pacemaker interrogation and reprogramming to asynchronous AOO mode was carried out before surgery, however, sinus pause occurred repeatedly during ablation pulse delivery. After the first sinus pause of 2.25 s there was a decrease in continuous arterial blood pressure (ABP). During the delivery of the second and third pulses, identical sinus pauses were observed due to failure to capture. However, the atrial-paced rhythm recovered instantly, and vital signs became acceptable. Although sinus pause recovered gradually, the duration thereof was increased by the delivery of more IRE pulses, with a subsequent abrupt decrease seen in blood pressure. The pacemaker was urgently reprogrammed to DOO mode, after which there were no further pacing failures and no hemodynamic adverse events. For patients with pacemakers, close cardiac monitoring in addition to the interrogation of the pacemaker during the electromagnetic interference (EMI) procedure is recommended, especially in the case of having a disease that may aggravate cardiac vulnerability, such as COVID-19.

Rectourethral fistula following focal irreversible electroporation for prostate cancer

A man in his 50s presented 4-week postirreversible electroporation (IRE) for low-to-intermediate risk prostate cancer with urinary symptoms, diarrhoea and passing fluid per rectum when urinating. Urine microscopy and sensitivities showed raised leucocytes, erythrocytes and pansensitive Escherichia coli. A CT cystogram revealed a rectourethral fistula (RUF). Urinary diversion with insertion of an indwelling catheter for 6 weeks was performed. A rigid cystoscopy 6 weeks after urinary diversion revealed that the fistula was still present, confirmed by intraoperative contrast. The fistula was repaired with diathermy and a fibrin glue. The patient reported resolution of urinary and bowel symptoms. This is the first case report in the literature of an RUF following IRE for prostate cancer. It is important to report these rare complications as novel treatments become more common across the world.Background

Real-Time MRI-Guided Prostate Interventions

Simple Summary

Magnetic resonance imaging has shown to be a reliable imaging method for detecting clinically significant prostate cancer and directly targeting lesions during biopsy. As newer treatment methods emerge, the role of MRI in minimally-invasive (focal) treatment of prostate cancer is also increasing. Here, we review the real-time MRI-guided prostate interventions for prostate cancer diagnosis and treatment, focusing on the technical aspects of each modality.

Abstract

Prostate cancer (PCa) is the second most common cause of cancer death in males. Targeting MRI-visible lesions has led to an overall increase in the detection of clinically significant PCa compared to the prior practice of random ultrasound-guided biopsy of the prostate. Additionally, advances in MRI-guided minimally invasive focal treatments are providing new options for patients with PCa. This review summarizes the currently utilized real-time MRI-guided interventions for PCa diagnosis and treatment.