A prospective development study investigating focal irreversible electroporation in men with localised prostate cancer: Nanoknife Electroporation Ablation Trial (NEAT)

Examining the application of the IDEAL framework in the reporting and evaluation of innovative invasive procedures: secondary qualitative analysis of a systematic review

OBJECTIVES

The development of new surgical procedures is fundamental to advancing patient care. The Idea, Developments, Exploration, Assessment and Long-term (IDEAL) framework describes study designs for stages of innovation. It can be difficult to apply due to challenges in defining and identifying innovative procedures. This study examined how the IDEAL framework is operationalised in real-world settings; specifically, the types of innovations evaluated using the framework and how authors justify their choice of IDEAL study design.

DESIGN

Secondary qualitative analysis of a systematic review.

DATA SOURCES

Citation searches (Web of Science and Scopus) identified studies following the IDEAL framework and citing any of the ten key IDEAL/IDEAL_D papers.

ELIGIBILITY CRITERIA

Studies of invasive procedures/devices of any design citing any of the ten key IDEAL/IDEAL_D papers.

DATA EXTRACTION AND SYNTHESIS

All relevant text was extracted. Three frameworks were developed, namely: (1) type of innovation under evaluation; (2) terminology used to describe stage of innovation and (3) reported rationale for IDEAL stage.

RESULTS

48 articles were included. 19/48 described entirely new procedures, including those used for the first time in a different clinical context (n=15/48), reported as IDEAL stage 2a (n=8, 53%). Terminology describing stage of innovation was varied, inconsistent and ambiguous and was not defined. Authors justified their choice of IDEAL study design based on limitations in published evidence (n=36) and unknown feasibility and safety (n=32) outcomes.

CONCLUSION

Identifying stage of innovation is crucial to inform appropriate study design and governance decisions. Authors' rationale for choice of IDEAL stage related to the existing evidence base or lack of sufficient outcome data for procedures. Stage of innovation was poorly defined with inconsistent descriptions. Further work is needed to develop methods to identify innovation to inform practical application of the IDEAL framework. Defining the concept of innovation in terms of uncertainty, risk and degree of evidence may help to inform decision-making.

Effects of different applied voltages of irreversible electroporation on prostate cancer in a mouse model

As a non-thermal ablation method, irreversible electroporation (IRE) has been widely investigated in the treatment of prostate cancer. However, no consensus has been achieved on the optimal parameters of IRE for prostate cancer. Since high voltage is known to carry risks of muscle contraction and patient discomfort, it is crucial to identify the minimum but effective and safer applied voltage to inhibit tumor growth. In this study, the effect of different applied voltages of IRE on prostate cancer was evaluated in BALB/c nude mice. Mathematical simulation and measurement of the actual ablation area revealed a larger ablation area at a higher voltage. In in vivo experiment, except for the three different voltages applied, all groups received identical electrical conditions: pulse number, 180 (20 groups × 9 pulses/group); pulse width, 100 µs; pulse interval, 2 ms; distance between the electrodes, 5 mm; and electrode exposure length, 15 mm. Whilst the tumor volume initially decreased in the 500 V (1000 V/cm) and 700 V (1400 V/cm) groups and subsequently increased, only a transient increase followed by a continuous decrease until the sacrifice was observed in the 900 V (1800 V/cm) group. This result demonstrated a lasting effect of a higher applied voltage on tumor growth inhibition. The histological, immunohistochemical, and western blot findings all confirmed IRE-induced apoptosis in the treatment groups. Taken together, 900 V seemed to be the minimum applied voltage required to reduce tumor growth, though subsequent studies are anticipated to further narrow the voltage intervals and lower the minimum voltage required for tumor inhibition.

High-Frequency Pulsed Electric Field Ablation in Beagle Model for Treatment of Prostate Cancer

Simple Summary

Around 248,530 newly diagnosed in 2021, prostate cancer has been the most frequently diagnosed cancer in the USA. Rapid decellularization preserving acellular tissues is essential for accurate treatment and regeneration in affected areas. Our study aimed to assess the safety and efficacy of high-frequency pulsed electric field (HF-PEF) in a beagle model for the treatment of prostate cancer. We confirmed that HF-PEF of 1800 V/cm, 100 μs width, 2 ms interval successfully decellularized the prostate tissue after 4 hours, and the tissues were almost regenerated in 28 days. IRE with HF-PEF has therapeutic potential to treat prostate cancer while minimizing damage to the surrounding tissues.

Abstract

Conventional irreversible electroporation (IRE) with low-frequency pulsed electric field (LF-PEF) is used to induce cell death; however, it has several disadvantages including a long procedure time and severe muscle contraction due to high-voltage electric field. This study investigates a novel IRE protocol with high-frequency pulsed electric field (HF-PEF) of 500 Hz repetition to ablate the prostate tissue in beagles for treatment of prostate cancer. A finite element analysis was performed to validate optimal electrical field strength for the procedure. In total, 12 beagles received HF-PEF of 500 Hz and were sacrificed at 4 h, 4 days, and 28 days (3 each). The remaining three beagles underwent sham procedure. The outcomes of HF-PEF were assessed by histological responses. HF-PEF successfully decellularized the prostate tissues 4 h after the treatment. The prostate glands, duct, and urethra were well preserved after IRE with HF-PEF. The ablated prostatic tissues were gradually regenerated and appeared similar to the original tissues 28 d after IRE with HF-PEF. Moreover, electrocardiography and hematology demonstrated that IRE with HF-PEF did not seriously affect the cardiac tissue. HF-PEF was effective and safe in the beagle prostate and effectively induced the ablation and gradually recovered with cellular regeneration.

Outcome selection, measurement and reporting for new surgical procedures and devices: a systematic review of IDEAL/IDEAL-D studies to inform development of a core outcome set

BACKGROUND

Outcome selection, measurement and reporting for the evaluation of new surgical procedures and devices is inconsistent and lacks standardization. A core outcome set may promote the safe and transparent evaluation of surgical innovations. This systematic review examined outcome selection, measurement and reporting in studies conducted within the IDEAL (Idea, Development, Exploration, Assessment and Long-term monitoring) framework to examine current practice and inform the development of a core outcome set for early-phase studies of surgical procedures/devices.

METHODS

Web of Science and Scopus citation searches were performed to identify author-reported IDEAL/IDEAL-D studies for any surgical procedure/device. Outcomes were extracted verbatim, including contextual information regarding outcome selection and measurement. Outcomes were categorized to inform a conceptual framework of outcome domains relevant to evaluating innovation.

RESULTS

Some 48 studies were identified. Outcome selection, measurement and reporting varied widely across studies in different IDEAL stages. From 1737 outcomes extracted, 22 domains specific to evaluating innovation were conceptualized under seven broad categories: procedure completion success/failure; modifications; unanticipated events; surgeons' experiences; patients' experiences; resource use specific to the innovative procedure/device; and other innovation-specific outcomes. Most innovation-specific outcomes were measured and reported in only a small number of studies.

CONCLUSION

This review highlighted the need for guidance and standardization in outcome selection and reporting in the evaluation of new surgical procedures/devices. Novel outcome domains specific to innovation have been identified to establish a core outcome set for future evaluations of surgical innovations.

Prospective Feasibility Study of Single-Shot Antibiotic Prophylaxis in Transrectal Focal Ablation of Prostate Cancer

INTRODUCTION

Urinary tract infections (UTI) represent the most frequent complications after transrectal focal ablation of prostate cancer. Single-shot antibiotic prophylaxis for prevention has not yet been described.

METHODS

In this cohort study of patients who received a high-intensity focused ultrasound (HIFU) ablation of prostate cancer within a registered prospective single-arm trial, we analyzed posttreatment UTI (≤30 days after HIFU) related to perioperative antibiotic management in an exploratory analysis: single-shot prophylaxis or targeted treatment for bacteriuria. Potential risk factors associated with UTI were evaluated by uni- and multivariate regression analyses.

RESULTS

In total, 55 patients were eligible for analysis. Of these, 76.4% received antibiotic single-shot prophylaxis. UTI occurred in 10.7% of all patients, 5.4% developed fever, 3.6% required hospitalization. An antibiotic single-shot prophylaxis helped to protect 90.5% of men from infectious complications. Estimated effects indicate that a longer posttreatment catheterization (OR 3.38, 95% CI 0.47-27.08) and larger ablation volume (OR 4.85, 95% CI 0.61-107.49) might be associated with the highest risk for UTI after treatment.

CONCLUSION

Single-shot antibiotic prophylaxis compared to a targeted antibiotic treatment showed a similar effectivity to prevent patients from infectious complications and should be considered as an element of antibiotic stewardship. Further research on risk factors and antibiotic strategies is required.

Numerical simulation modeling of the irreversible electroporation treatment zone for focal therapy of prostate cancer, correlation with whole-mount pathology and T2-weighted MRI sequences

Background:

At present, it is not possible to predict the ablation zone volume following irreversible electroporation (IRE) for prostate cancer (PCa). This study aimed to determine the necessary electrical field threshold to ablate human prostate tissue in vivo with IRE.

Methods:

In this prospective multicenter trial, patients with localized PCa were treated with IRE 4 weeks before their scheduled radical prostatectomy. In 13 patients, numerical models of the electrical field were generated and compared with the ablation zone volume on whole-mount pathology and T2-weighted magnetic resonance imaging (MRI) sequences. Volume-generating software was used to calculate the ablation zone volumes on histology and MRI. The electric field threshold to ablate prostate tissue was determined for each patient.

Results:

A total of 13 patients were included for histological and simulation analysis. The median electrical field threshold was 550 V/cm (interquartile range 383–750 V/cm) for the software-generated histology volumes. The median electrical field threshold was 500 V/cm (interquartile range 386–580 V/cm) when the ablation zone volumes were used from the follow-up MRI.

Conclusions:

The electrical field threshold to ablate human prostate tissue in vivo was determined using whole-mount pathology and MRI. These thresholds may be used to develop treatment planning or monitoring software for IRE prostate ablation; however, further optimization of simulation methods are required to decrease the variance that was observed between patients.

Prostate cancer treated with irreversible electroporation: MRI-based volumetric analysis and oncological outcome

BACKGROUND

To assess multiparametric magnetic resonance imaging (mpMRI) characteristics in prostate cancer (PCa) before and after irreversible electroporation (IRE) and to investigate their correlation with the presence of post-operative recurrence of PCa.

METHODS

MpMRI was performed in 30 men with PCa prior to treatment, after 10 days and at 6 months. An additional scan at 1 year was available for 18 men. Two radiologists assessed retrospectively the following parameters by planimetry: tumour volume, necrotic volume (early post-treatment scan) and residual fibrosis. Residual tumour/recurrence were defined as a suspicious area within the treatment field scored ≥ 4 on a 1-to-5 scale. Oncological outcome was also assessed.

RESULTS

The median follow-up of the entire study was 16 months. Six men were undertreated and showed mpMRI recurrence after 6 months. At 1-year, three additional men had recurrence. Overall, four of these 9 men (44%) were retreated. The other five men did not receive any further treatment. Median time to re-treatment was 15 months. Median pre-treatment lesion volume was 0.65 cc, 0.66 cc and 0.43 cc on the different mpMRI sequences (T2-weighted, diffusion-weighted and dynamic contrast enhanced imaging). Median necrotic volume was 10.77 cc. Median overall residual fibrosis volumes were 0.84 cc and 0.95 cc at 6-month and 1-year mpMRI. Pre-treatment, necrotic and residual fibrosis volumes were significantly different (p < 0.001). Pre-treatment tumour volumes on diffusion-weighted imaging and necrotic volumes were correlated (r = 0.18; p = 0.02).

CONCLUSIONS

MpMRI is able to visualise the IRE ablation effects in men with PCa. MpMRI-derived parameters - such as tumour, necrotic and fibrosis volumes - can be measured and are potentially useful for assessing efficacy in the medium term, as with other ablative techniques.

Irreversible Electroporation for Nonthermal Tumor Ablation in Patients with Locally Advanced Pancreatic Cancer: Initial Clinical Experience in Japan

Objective To evaluate irreversible electroporation (IRE) for locally advanced pancreatic cancer (LAPC). Methods This study was approved by our local review board. Eight patients with histologically proven LAPC ≤5 cm were prospectively enrolled to undergo ultrasound-guided IRE. The primary endpoint was complications within 90 days. Secondary outcomes were the overall survival (OS) and time to local progression. Safety was assessed using Common Terminology Criteria for Adverse Events Version 4.0. Results All patients were treated successfully. The median procedure time was 150 min. The median largest tumor diameter was 29.5 mm (20.0-48.0 mm) in the pancreatic head (n=5) and body (n=3). Open (n=4) and percutaneous (n=4) approaches were used. No patients died within 90 days after IRE. There were 5 minor complications in 3 patients and 4 major complications in 3 patients. The incidence rates of major complications did not differ significantly between the approaches. The median time to local progression after IRE was 12.0 months, and the median OS was 17.5 months from IRE and 24.0 months from the diagnosis, with no significant differences between the approaches. Conclusions Percutaneous and open IRE may be acceptable for patients with LAPC (despite some major adverse events) and may represent a useful new therapeutic option.

Vascular Interventional Radiology-Guided Photothermal Therapy of Colorectal Cancer Liver Metastasis with Theranostic Gold Nanorods

We report sub-100 nm optical/magnetic resonance (MR)/X-ray contrast-bearing theranostic nanoparticles (TNPs) for interventional image-guided photothermal therapy (PTT) of solid tumors. TNPs were composed of Au@Gd2O3:Ln (Ln = Yb/Er) with X-ray contrast (∼486 HU; 1014 NPs/mL, 0.167 nM) and MR contrast (∼1.1 × 108 mM-1 S-1 at 9.4 T field strength). Although TNPs are deposited in tumors following systemic administration via enhanced permeation and retention effect, the delivered dose to tumors is typically low; this can adversely impact the efficacy of PTT. To overcome this limitation, we investigated the feasibility of site-selective hepatic image-guided delivery of TNPs in rats bearing colorectal liver metastasis (CRLM). The mesenteric vein of tumor-bearing rats was catheterized, and TNPs were infused into the liver by accessing the portal vein for site-selective delivery. The uptake of TNPs with hepatic delivery was compared with systemic administration. MR imaging confirmed that delivery via the hepatic portal vein can double the CRLM tumor-to-liver contrast compared with systemic administration. Photothermal ablation was performed by inserting a 100 μm fiber-optic carrying 808 nm light via a JB1, 3-French catheter for 3 min under DynaCT image guidance. Histological analysis revealed that the thermal damage was largely confined to the tumor region with minimal damage to the adjacent liver tissue. Transmission electron microscopy imaging validated the stability of core-shell structure of TNPs in vivo pre- and post-PTT. TNPs comprising Gd-shell-coated Au nanorods can be effectively employed for the site-directed PTT of CRLM by leveraging interventional radiology methods.

The prostate cancer focal therapy

Despite prostate cancer (PCa) is the leading form of non-cutaneous cancer in men, most patients with PCa die with disease rather than of the disease. Therefore, the risk of overtreatment should be considered by clinicians who have to distinguish between patients with high risk PCa (who would benefit from radical treatment) and patients who may be managed more conservatively, such as through active surveillance or emerging focal therapy (FT). The aim of FT is to eradicate clinically significant disease while protecting key genito-urinary structures and function from injury. While effectiveness studies comparing FT with conventional care options are still lacking, the rationale supporting FT relies on evidence-based advances such as the understanding of the index lesion's central role in the natural history of the PCa and the improvement of multiparametric magnetic resonance imaging (mpMRI) in the detection and risk stratification of PCa. In this literature review, we want to highlight the rationale for FT in PCa management and the current evidence on patient eligibility. Furthermore, we summarize the best imaging modalities to localize the target lesion, describe the current FT techniques in PCa, provide an update on their oncological outcomes and highlight trends for future research.

In vivo evaluation of bronchial injury of irreversible electroporation in a porcine lung ablation model by using laboratory, pathological, and CT findings

Irreversible electroporation (IRE) creates permanent pores in the cell membrane, leading to irreversible cell death. In this study, the impact of IRE on bronchial injury was comprehensively examined in a timed series study. Altogether, 8 Bama miniature pigs were included in this study and were randomly assigned to experimental and control groups. The experimental group underwent IRE that was guided and monitored by spiral computed tomography (CT). The monopole probe of the IRE was positioned at the right pulmonary hilum. Specimens were collected at 0 h, 2 h, 2 d, 7 d, and 14 d after the IRE procedure for a pathological examination. A small amount of needle-tract bleeding occurred in two animals, and mild pneumothorax occurred in another. IRE can elicit acute bronchial inflammation, bleeding, and mucosal injury, but severe complications were not found. Pathological examinations and transmission electron microscopy (TEM) showed dead vascular epithelium cells in the region of the ablation, while the bronchioli and the vascular extracellular matrix were preserved. At 2 hours post-IRE, there were marked increases in bronchoalveolar macrophages (P<0.001), but the inflammation could recover after 14 days and showed no statistical significance when compared with the control group at the same time. In conclusion, CT-guided IRE ablation can elicit acute but recoverable bronchial inflammation, bleeding, and mucosal injury in porcine lung tissues. However, longer follow-up is still required to establish an evaluation of the long-term safety.

MRI-TRUS fusion for electrode positioning during irreversible electroporation for treatment of prostate cancer

We aimed to introduce an approach for image-guided positioning of electrodes for irreversible electroporation (IRE) in patients with prostate cancer using a magnetic resonance imaging-transrectal ultrasonography (MRI-TRUS) fusion technique. In 10 consecutive patients with biopsy-proven Gleason score ≤3+4 prostate cancer, 19 G electrodes were inserted into the prostate using a transperineal access. Magnetic resonance images of the prostate acquired before IRE were fused with transrectal ultrasound images acquired during IRE. The position of the ultrasound probe was tracked via a sensor and corresponding magnetic resonance images were calculated in real-time. While MRI allowed delineation of the target volume, the position of the electrodes could be visualized on ultrasound images; the distance between individual electrode pairs was measured. Based on these measurements the software installed on the IRE unit was able to calculate the voltage necessary to generate the electric field for ablation. Using contrast-enhanced ultrasound, changes in perfusion within the ablation zone after IRE were documented. This technique allowed positioning of the electrodes around the target volume under image guidance in all patients treated with IRE. The target lesion and a safety margin were covered within the estimated ablation zone. MRI-TRUS guidance for IRE combines the advantages of good visualization of the target lesion on MRI with the ability of ultrasound to acquire imaging in real-time with a mobile device.

IDEAL 2a Phase II Study of Ultrafocal Brachytherapy for Low- and Intermediate-risk Prostate Cancer

PURPOSE

Focal therapy of prostate cancer requires precise positioning of therapeutic agents within well-characterized index tumors (ITs). We assessed the feasibility of low-dose-rate ultrafocal brachytherapy.

METHODS AND MATERIALS

The present study was an institutional review board-approved European Clinical Trials Database-registered phase II protocol. Patients referred (October 2013 to August 2016) for active surveillance (prostate-specific antigen <10 ng/mL, cT1c-cT2a, Gleason score on referring biopsy specimens ≤6 (3+3), ≤3 positive biopsy cores, ≤50% of cancer) were preselected. Inclusion was confirmed when complementary image-guided biopsy findings informed a single Prostate Imaging Reporting and Data System (PI-RADS) ≥3, Gleason score ≤7a (3+4) lesion. A ultrasound-visible ancillary marker was positioned within the IT using a magnetic resonance imaging (MRI)/3-dimensional transrectal ultrasound (TRUS) elastic fusion-guided system (Koelis). Ultrafocal transperineal delivery of ¹²⁵I seeds used classic 2-dimensional TRUS (Bard-FlexFocus) and dose optimization (Variseed Treatment Planning System). Following Simon's optimal design, 17 patients were required to assess the feasibility of delivering ≥95% of the prescribed dose (160 Gy) to the IT (primary objective). Adverse events (Common Terminology Criteria for Adverse Events) and quality of life (5-item International Index of Erectile Function, International Prostate Symptom Score) were recorded. One-year control biopsy specimens were obtained from the IT and untreated segments.

RESULTS

Of the 44 preselected patients, 27 did not meet the inclusion criteria. Of the 17 ultrafocal brachytherapy-treated patients, 16 met the primary objective (per protocol success). The prescription dose was delivered to 14.5% ± 6.4% of the prostate volume, resulting in negligible urethral and rectal irradiation and toxicity. No recurrence was evidenced on the 1-year follow-up MRI studies or IT biopsy specimens. Seven nonclinically significant cancers and one Gleason score 7a (3+4) cancer (salvage prostatectomy) were observed in the untreated parenchyma.

CONCLUSIONS

Recent technology has allowed for selective and effective brachytherapy of small MRI targets.

Focused Transhepatic Electroporation Mediated by Hypersaline Infusion through the Portal Vein in Rat Model. Preliminary Results on Differential Conductivity

Background

Spread hepatic tumours are not suitable for treatment either by surgery or conventional ablation methods. The aim of this study was to evaluate feasibility and safety of selectively increasing the healthy hepatic conductivity by the hypersaline infusion (HI) through the portal vein. We hypothesize this will allow simultaneous safe treatment of all nodules by irreversible electroporation (IRE) when applied in a transhepatic fashion.

Material and methods

Sprague Dawley (Group A, n = 10) and Athymic rats with implanted hepatic tumour (Group B, n = 8) were employed. HI was performed (NaCl 20%, 3.8 mL/Kg) by trans-splenic puncture. Deionized serum (40 mL/Kg) and furosemide (2 mL/Kg) were simultaneously infused through the jugular vein to compensate hypernatremia. Changes in conductivity were monitored in the hepatic and tumour tissue. The period in which hepatic conductivity was higher than tumour conductivity was defined as the therapeutic window (TW). Animals were monitored during 1-month follow-up. The animals were sacrificed and selective samples were used for histological analysis.

Results

The overall survival rate was 82.4% after the HI protocol. The mean maximum hepatic conductivity after HI was 2.7 and 3.5 times higher than the baseline value, in group A and B, respectively. The mean maximum hepatic conductivity after HI was 1.4 times higher than tumour tissue in group B creating a TW to implement selective IRE.

Conclusions

HI through the portal vein is safe when the hypersaline overload is compensated with deionized serum and it may provide a TW for focused IRE treatment on tumour nodules.

Focal Ablation of Early-Stage Prostate Cancer: Candidate Selection, Treatment Guidance, and Assessment of Outcome

Prostate cancer lesions smaller than 0.5 m³, or Gleason pattern 3, are likely clinically insignificant. Clinically significant disease is often limited to a single index lesion. Focal ablation targets this index lesion, maintains oncological control, and minimizes complications by preserving healthy prostate tissue. Template mapping biopsy or multiparametric MRI-targeted biopsies are used to identify appropriate index lesions. Multiple energy modalities have been tested, including high-intensity frequency ultrasound, cryoablation, laser ablation, photodynamic therapy, focal brachytherapy, radiofrequency ablation, irreversible electroporation. Outcome is assessed by biopsy of the target area, triggered by prostate-specific antigen measurements or MRI imaging, or performed per protocol at 12 months.

An evaluation of irreversible electroporation thresholds in human prostate cancer and potential correlations to physiological measurements

Irreversible electroporation (IRE) is an emerging cancer treatment that utilizes non-thermal electric pulses for tumor ablation. The pulses are delivered through minimally invasive needle electrodes inserted into the target tissue and lead to cell death through the creation of nanoscale membrane defects. IRE has been shown to be safe and effective when performed on tumors in the brain, liver, kidneys, pancreas, and prostate that are located near critical blood vessels and nerves. Accurate treatment planning and prediction of the ablation volume require a priori knowledge of the tissue-specific electric field threshold for cell death. This study addresses the challenge of defining an electric field threshold for human prostate cancer tissue. Three-dimensional reconstructions of the ablation volumes were created from one week post-treatment magnetic resonance imaging (MRIs) of ten patients who completed a clinical trial. The ablation volumes were incorporated into a finite element modeling software that was used to simulate patient-specific treatments, and the electric field threshold was calculated by matching the ablation volume to the field contour encompassing the equivalent volume. Solutions were obtained for static tissue electrical properties and dynamic properties that accounted for electroporation. According to the dynamic model, the electric field threshold was 506 ± 66 V/cm. Additionally, a potentially strong correlation (r = −0.624) was discovered between the electric field threshold and pre-treatment prostate-specific antigen levels, which needs to be validated in higher enrollment studies. Taken together, these findings can be used to guide the development of future IRE protocols.

Focal therapy as primary treatment for localized prostate cancer: definition, needs and future

Focal therapy (FT) may offer a promising treatment option in the field of low to intermediate risk localized prostate cancer. The aim of this concept is to combine minimal morbidity with cancer control as well as maintain the possibility of retreatment. Recent advances in MRI and targeted biopsy has improved the diagnostic pathway of prostate cancer and increased the interest in FT. However, before implementation of FT in routine clinical practice, several challenges are still to overcome including patient selection, treatment planning, post-therapy monitoring and definition of oncologic outcome surrogates. In this article, relevant questions regarding the key steps of FT are critically discussed and the main available energy modalities are analyzed taking into account their advantages and unmet needs.

Nanoknife Electroporation Ablation Trial: A Prospective Development Study Investigating Focal Irreversible Electroporation for Localized Prostate Cancer

PURPOSE

Irreversible electroporation has attractive attributes for focal ablation, namely nonthermal effect, precise demarcation of treatment and tissue selectivity. We report a prospective development study investigating focal irreversible electroporation.

MATERIALS AND METHODS

A total of 20 men with certain characteristics were recruited for study, including a visible index lesion on anterior magnetic resonance imaging that was concordant with transperineal targeted and template prostate mapping biopsy, absent clinically significant disease noted elsewhere (University College London definition 2) and prostate specific antigen 15 ng/ml or less. Our primary objective was to determine the side effect profile at 12 months. Secondary objectives included the domain specific toxicity profile using patient reported outcomes and early disease control using magnetic resonance imaging targeted biopsy.

RESULTS

A total of 19 patients with median age of 60 years (IQR 53-66) and median prostate specific antigen 7.75 ng/ml (IQR 5.5-10.03) were treated. Of the patients 16 were available for estimating the first outcome as 1 was lost to followup and 2 had received another form of treatment by study end. All 16 men had pad-free/leak-free continence at 12 months. The proportion of men with erection sufficient for penetration decreased from 12 of 16 (75%) to 11 of 16 (69%). No serious adverse events were recorded. There was a statistically significant improvement in urinary symptoms according to changes in UCLA-EPIC (UCLA Expanded Prostate Cancer Index Composite) and I-PSS (International Prostate Symptom Score) (p = 0.039 and 0.001, respectively). Erectile function remained stable according to the change in IIEF-15 (15-Item International Index of Erectile Function) (p = 0.572). Median prostate specific antigen significantly decreased to 1.71 ng/ml (p = 0.001). One man refused followup biopsy. No residual disease was found in 11 patients (61.1%). One man (5.6%) harbored clinically insignificant disease and the remaining 6 (33.3%) harbored clinically significant disease.

CONCLUSIONS

Focal irreversible electroporation has low genitourinary toxicity. Additional studies are needed to optimize patient selection and treatment parameters.

Low temperature plasmas as emerging cancer therapeutics: the state of play and thoughts for the future

The field of plasma medicine has seen substantial advances over the last decade, with applications developed for bacterial sterilisation, wound healing and cancer treatment. Low temperature plasmas (LTPs) are particularly suited for medical purposes since they are operated in the laboratory at atmospheric pressure and room temperature, providing a rich source of reactive oxygen and nitrogen species (RONS). A great deal of research has been conducted into the role of reactive species in both the growth and treatment of cancer, where long-established radio- and chemo-therapies exploit their ability to induce potent cytopathic effects. In addition to producing a plethora of RONS, LTPs can also create strong electroporative fields. From an application perspective, it has been shown that LTPs can be applied precisely to a small target area. On this basis, LTPs have been proposed as a promising future strategy to accurately and effectively control and eradicate tumours. This review aims to evaluate the current state of the literature in the field of plasma oncology and highlight the potential for the use of LTPs in combination therapy. We also present novel data on the effect of LTPs on cancer stem cells, and speculatively outline how LTPs could circumvent treatment resistance encountered with existing therapeutics.

Standardization of definitions in focal therapy of prostate cancer: report from a Delphi consensus project

PURPOSE

To reach standardized terminology in focal therapy (FT) for prostate cancer (PCa).

METHODS

A four-stage modified Delphi consensus project was undertaken among a panel of international experts in the field of FT for PCa. Data on terminology in FT was collected from the panel by three rounds of online questionnaires. During a face-to-face meeting on June 21, 2015, attended by 38 experts, all data from the online rounds were reviewed and recommendations for definitions were formulated.

RESULTS

Consensus was attained on 23 of 27 topics; Targeted FT was defined as a lesion-based treatment strategy, treating all identified significant cancer foci; FT was generically defined as an anatomy-based (zonal) treatment strategy. Treatment failure due to the ablative energy inadequately destroying treated tissue is defined as ablation failure. In targeting failure the energy is not adequately applied to the tumor spatially and selection failure occurs when a patient was wrongfully selected for FT. No definition of biochemical recurrence can be recommended based on the current data. Important definitions for outcome measures are potency (minimum IIEF-5 score of 21), incontinence (new need for pads or leakage) and deterioration in urinary function (increase in IPSS >5 points). No agreement on the best quality of life tool was established, but UCLA-EPIC and EORTC-QLQ-30 were most commonly supported by the experts. A complete overview of statements is presented in the text.

CONCLUSION

Focal therapy is an emerging field of PCa therapeutics. Standardization of definitions helps to create comparable research results and facilitate clear communication in clinical practice.

Irreversible Electroporation (IRE): Standardization of Terminology and Reporting Criteria for Analysis and Comparison

BACKGROUND

Irreversible electroporation (IRE) as newer ablation modality has been introduced and its clinical niche is under investigation. At present just one IRE system has been approved for clinical use and is currently commercially available (NanoKnife® system). In 2014, the International Working Group on Image-Guided Tumor Ablation updated the recommendation about standardization of terms and reporting criteria for image-guided tumor ablation. The IRE method is not covered in detail. But the non-thermal IRE method and the NanoKnife System differ fundamentally from established ablations techniques, especially thermal approaches, e.g. radio frequency ablation (RFA).

MATERIAL/METHODS

As numerous publications on IRE with varying terminology exist so far - with numbers continuously increasing - standardized terms and reporting criteria of IRE are needed urgently. The use of standardized terminology may then allow for a better inter-study comparison of the methodology applied as well as results achieved.

RESULTS

Thus, the main objective of this document is to supplement the updated recommendation for image-guided tumor ablation by outlining a standardized set of terminology for the IRE procedure with the NanoKnife Sytem as well as address essential clinical and technical informations that should be provided when reporting on IRE tumor ablation.

CONCLUSIONS

We emphasize that the usage of all above recommended reporting criteria and terms can make IRE ablation reports comparable and provide treatment transparency to assess the current value of IRE and provide further development.

Contemporary Management of Prostate Cancer

Prostate cancer represents a spectrum ranging from low-grade, localized tumors to devastating metastatic disease. We discuss the general options for treatment and recent developments in the field.

Practical guide to the Idea, Development and Exploration stages of the IDEAL Framework and Recommendations

BACKGROUND

Evaluation of new surgical procedures is a complex process challenged by evolution of technique, operator learning curves, the possibility of variable procedural quality, and strong treatment preferences among patients and clinicians. Preliminary studies that address these issues are needed to prepare for a successful randomized trial. The IDEAL (Idea, Development, Exploration, Assessment and Long-term follow-up) Framework and Recommendations provide an integrated step-by-step evaluation pathway that can help investigators achieve this.

METHODS

A practical guide was developed for investigators evaluating new surgical interventions in the earlier phases before a randomized trial (corresponding to stages 1, 2a and 2b of the IDEAL Framework). The examples and practical tips included were chosen and agreed upon by consensus among authors with experience either in designing and conducting IDEAL format studies, or in helping others to design such studies. They address the most common challenges encountered by authors attempting to follow the IDEAL Recommendations.

RESULTS

A decision aid has been created to help identify the IDEAL stage of an innovation from literature reports, with advice on how to design and report the IDEAL study formats discussed, along with the ethical and scientific rationale for specific recommendations.

CONCLUSION

The guide helps readers and researchers to understand and implement the IDEAL Framework and Recommendations to improve the quality of evidence supporting surgical innovation.

Focal irreversible electroporation for prostate cancer: functional outcomes and short-term oncological control

BACKGROUND

Current data on the use of irreversible electroporation (IRE) in the treatment of prostate cancer (PCa) is limited. We aim to evaluate the safety, short-term functional and oncological outcomes of focal IRE in low-intermediate risk PCa.

METHODS

Between February 2013 and May 2014, 32 consecutive men underwent IRE at a single centre. Patients with low-intermediate risk PCa who had not received previous PCa treatment were included for analysis. The tumour was ablated using 3-6 electrodes, ensuring a minimum 5-mm safety margin around the visible magnetic resonance imaging (MRI) lesion. Follow-up included recording Clavien complications, Expanded Prostate Cancer Index Composite (EPIC) questionnaires (baseline, 1.5, 3, 6 months), 6-month multi-parametric MRI (mp-MRI) and 7-month biopsy. Findings on mp-MRI and biopsy were sub-divided into infield, adjacent or outfield of the treatment zone.

RESULTS

Twenty-five men were included for final analysis. Safety follow-up revealed one Clavien Grade 3 complication and five Grade 1 complications. Functional follow-up confirmed no significant change in American Urological Association urinary symptom score, sexual or bowel function. Infield, there were no suspicious findings on mp-MRI (n=24) or biopsy (n=21) in all patients. Adjacent to the treatment zone, five (21%) had suspicious findings on mp-MRI with four (19%) proving to be significant on biopsy. Outfield, there were two (8%) with suspicious findings on mp-MRI and one (5%) significant finding on biopsy. For the five patients with significant findings on follow-up biopsy, one is awaiting repeat IRE, one had radical prostatectomy and three remained on active surveillance.

CONCLUSIONS

In selected patients with low-intermediate risk PCa, focal IRE appears to be safe with minimal morbidity. There were no infield recurrences and 76% of patients were histologically free of significant cancer at 8 months. Almost all recurrences were adjacent to the treatment zone, and this was addressed by widening the treatment margins.

Percutaneous CT-guided irreversible electroporation followed by chemotherapy as a novel neoadjuvant protocol in locally advanced pancreatic cancer: Our preliminary experience

INTRODUCTION

Irreversible electroporation (IRE) is a non-thermal ablation technique recently used in pancreatic cancer. In our prospective study we evaluated safety, feasibility and efficacy of a neoadjuvant protocol based on CT-guided percutaneous IRE followed by chemotherapy in patients with locally advanced pancreatic cancer (LAPC).

METHODS

We performed CT-guided percutaneous IRE in 20 patients with LAPC, followed by a combination of gemcitabine (1000 mg/mq) and oxaliplatin (100 mg/mq) biweekly. Imaging follow-up was performed by a contrast enhanced CT scan at 1, 3, 6 months and then every 3 months.

RESULTS

No major complications occurred. Two patients died 3 and 4 months after IRE because of rapidly progressive disease. In the remaining 18 patients 6-month imaging follow-up showed a mean lesions volumetric decrease percentage of 42.89% (95% Confidence Interval: 34.90-54.88%). Thanks to lesions downstaging, three patients underwent R0 resection. At last available follow-up (mean follow-up 91 months; range 6-14), imaging showed no disease progression or post-surgical relapse in all 18 cases. The mean estimated survival was 12,950 months (95% CI: 11,570-14,332).

CONCLUSIONS

Our preliminary study suggests that IRE followed by chemotherapy is safe, feasible and effective in producing local control of LAPC, with a possible downstaging effect to resectable lesions.

Systematic Review of the Efficacy and Safety of High-intensity Focussed Ultrasound for Localised Prostate Cancer

CONTEXT

High-intensity focussed ultrasound (HIFU) has been used for 10 yr to treat localised prostate cancer (PCa).

OBJECTIVE

To evaluate systematically the evidence on the efficacy and side effects of HIFU in the primary treatment of localised PCa.

EVIDENCE ACQUISITION

We performed a critical review and appraisal of Medline (Ovid), PreMedline, Embase, and Cochrane Database of Systematic Reviews publications on HIFU up to May 2013. One systematic review and 18 primary studies, all case series, were eligible.

EVIDENCE SYNTHESIS

Outcomes were summarised and evidence was evaluated using Grading of Recommendations, Assessment, Development and Evaluation methodology. Low-quality evidence suggests an overall survival rate after Ablatherm HIFU ranging from 80% to 89% for >5 yr. The PCa survival rate ranges from 97% to 99% for >5 yr. Effect of HIFU on quality of life remains undetermined. Erectile dysfunction was the most frequent adverse event reported from zero but up to 74% of patients. Adverse events affecting the urinary tract occurred in 0.7-31% of patients, bladder outlet obstruction in 4-51.5%, and they were more frequent in patients who had transurethral resection of the prostate the same day or within 2 d of HIFU. Outcomes vary for low- and high-risk categories.

CONCLUSIONS

Good quality evidence on the efficacy of HIFU treatment for localised PCa is lacking.

PATIENT SUMMARY

We reviewed all the data on treatment with high-intensity focussed ultrasound (HIFU) for localised prostate cancer (PCa). The quality of the evidence is very low because the information is based on a series of patients who received HIFU treatment with no comparison with active surveillance or radical treatment. Case series suggest an overall survival rate up to 89% and a PCa survival rate up to 99% after 5 yr, but these numbers vary according to the patient's risk category. Longer term and effects on quality of life are unknown.

Irreversible electroporation for nonthermal tumor ablation in patients with hepatocellular carcinoma: initial clinical experience in Japan

PURPOSE

This clinical study was conducted to evaluate the safety and short-term outcomes of irreversible electroporation (IRE) for the treatment of patients with hepatocellular carcinoma (HCC) in Japan.

MATERIALS AND METHODS

The study was designed in a prospective setting. Five patients (3 men and 2 women; mean age, 66.6 ± 5.8 years) with 6 HCCs were enrolled and treated using percutaneous ultrasound (US)-guided IRE. Safety was assessed based on adverse events and laboratory values. Local control was assessed using contrast-enhanced US with a perflubutane microbubble contrast agent, contrast-enhanced multiphase CT, and gadoxetic acid-enhanced MRI (EOB-MRI) at designated points.

RESULTS

The tumors ranged in diameter from 11 to 28 mm (mean diameter, 17.5 ± 6.3 mm). Five of the 6 tumors (83 %) were successfully treated, with no local recurrence to date (mean follow-up 244 ± 55 days). In 1 lesion located in liver segment 1, residual tumor was diagnosed at 7 days after intervention by follow-up EOB-MRI. No serious complications related to the IRE procedure were observed.

CONCLUSION

The results of this study suggest that image-guided percutaneous IRE can achieve satisfactory local disease control, particularly for small HCCs, and is well tolerated by patients.

A prospective Phase 2a pilot study investigating focal percutaneous irreversible electroporation (IRE) ablation by NanoKnife in patients with localised renal cell carcinoma (RCC) with delayed interval tumour resection (IRENE trial)

INTRODUCTION

Focal ablation therapy is playing an increasing role in oncology and may reduce the toxicity of current surgical treatments while achieving adequate oncological benefit. Irreversible electroporation (IRE) has been proposed to be tissue-selective with potential advantages compared with current thermal-ablation technologies or radiotherapy. The aim of this pilot trial is to determine the effectiveness and feasibility of focal percutaneous IRE in patients with localised renal cell cancer as a uro-oncological tumour model.

METHODS

Prospective, monocentric Phase 2a pilot study following current recommendations, including those of the International Working Group on Image-Guided Tumor Ablation. Twenty patients with kidney tumour (T1aN0M0) will be recruited. This sample permits an appropriate evaluation of the feasibility and effectiveness of image-guided percutaneous IRE ablation of locally confined kidney tumours as well as functional outcomes. Percutaneous biopsy for histopathology will be performed before IRE, with magnetic-resonance imaging one day before and 2, 7, 27 and 112 days after IRE; at 28 days after IRE the tumour region will be completely resected and analysed by ultra-thin-layer histology.

DISCUSSION

The IRENE study will investigate over a short-term observation period (by magnetic-resonance imaging, post-resection histology and assessment of technical feasibility) whether focal IRE, as a new ablation procedure for soft tissue, is feasible as a percutaneous, tissue-sparing method for complete ablation and cure of localised kidney tumours. Results from the kidney-tumour model can provide guidance for designing an effectiveness and feasibility trial to assess this new ablative technology, particularly in uro-oncology.

Histological outcomes after focal high-intensity focused ultrasound and cryotherapy

Introduction

Focal therapy has increasingly become an accepted treatment option for patients with localised prostate cancer. Most follow-up protocols use a mixture of protocol biopsies or “for cause” biopsies triggered by a rising PSA. In this paper, we discuss the histological outcomes from these biopsies and their use in guiding subsequent management and trial development.

Methods

We conducted a literature search and reviewed the post-treatment biopsy results from studies on focal HIFU and focal cryotherapy. We subsequently reviewed the results of three recently published consensus statements released discussing many of the issues concerning focal therapy.

Results

Research suggests that 1 in 5 of all post-treatment biopsies after focal therapy are positive. However, the majority of these seemed to be from the untreated portion of the gland or met criteria for clinically insignificant disease. The histological outcomes from focal therapy are promising and confirm its effectiveness in the short to medium term. Furthermore re-treatment is possible whilst maintaining a low-side-effect profile.

Conclusion

Debate is ongoing about the clinical significance of various levels of residual disease after focal therapy and the exact threshold at which to call failure within a patient who has had focal therapy.