Pilot Study to Assess Safety and Clinical Outcomes of Irreversible Electroporation for Partial Gland Ablation in Men with Prostate Cancer

Personalized Treatment Strategy in "Low-Risk Prostate Cancer Active Surveillance Candidates" Using Irreversible Electroporation: Prospective Evaluation of Feasibility, Morbidity, Functional and Oncological Outcomes

PURPOSE

To evaluate the morbidity, functional and oncological outcome of irreversible electroporation (IRE) as a focal therapy for prostate cancer (PCa) when used in "active surveillance (AS)" candidates refusing standard treatment options.

MATERIALS AND METHODS

IRE was performed under general anaesthesia, and the transurethral catheter was removed one day after intervention in all patients. Pre- and post-interventional voiding parameters (measured by International Prostate Symptom Score Questionnaire [IPSS], uroflowmetry and post-void residue) were compared. Follow-up (FU) was observed over a minimum of six months, including oncological outcome (controlled by multiparametric magnetic resonance imaging, rebiopsy, prostate-specific antigen dynamic as well as the need and type of secondary treatment) and general functional outcome (International Index of Erectile Function Questionnaire, satisfaction of the procedure).

RESULTS

Twenty-four patients refusing AS or standard treatment with a median FU of 18.7 months were included. IPSS showed nine patients with mild, 12 with moderate and two with severe obstructive voiding symptoms pre-intervention (focal IRE). Median IPSS pre-IRE was 9 points, 8.5 (p=0.341) at six months and 10 (p=0.392) after 12 months, respectively. Pre-IRE maximum urinary flow (Qmax) (median: 16.1±8.0 mL/sec) and Qmax after catheter removal (16.2±7.6 mL/sec) did not differ significantly (p=0.904). Thirteen PCa recurrences occurred (54.2%). Out-of-lesion-PCa was found in 12/13 patients (92.3%), while 4/13 patients showed in-lesion-PCa recurrence simultaneously (30.8%). In one patient, there was an in-lesion-PCa recurrence only (7.7%). Six out of 24 patients (25.0%) received a secondary treatment. All patients were satisfied with the IRE procedure.

CONCLUSIONS

Focal IRE underperforms regarding the overall oncological outcome and should not be offered as an equivalent therapy to established curative treatment strategies. Nevertheless, under a strict FU regimen, its lack of significant additional morbidity compared to an active surveillance strategy makes IRE a feasible alternative for low-risk PCa in highly selected patients as a personalised approach.

Irreversible Electroporation for the Focal Treatment of Prostate Cancer: A Systematic Review

PURPOSE

Irreversible electroporation (IRE) is a promising alternative treatment for low-intermediate-risk localized prostate cancer. In this systematic review we aim to evaluate the safety profile and functional and oncological outcomes of this new technique.

MATERIALS AND METHODS

A systematic review of the literature was performed on PubMed, EMBASE, and Scopus up to 24 August 2023. Nineteen studies were analyzed, including 12 prospective studies and 7 retrospective studies. A total of 1,452 patients underwent IRE as the sole primary treatment modality.

RESULTS

The in-field clinically significant prostate cancer rate was reported between 0%-15.6% in the repeat biopsy. The retreatment rate was reported from 8% to 36.6%. The 3 years failure-free survival was presented between 90%-96.8%. The post-operative pad-free rate ranged between 96.7%-100%. Greater heterogeneity exists considering the change in erectile function. The most common reported complications were urinary tract infection and hematuria. Major complications were rare.

CONCLUSIONS

These results underline that IRE achieves favorable oncological control with an excellent safety profile, in the meantime preserving patients' urinary and erectile function.

Electrolysis products, reactive oxygen species and ATP loss contribute to cell death following irreversible electroporation with microsecond-long pulsed electric fields

Membrane permeabilization and thermal injury are the major cause of cell death during irreversible electroporation (IRE) performed using high electric field strength (EFS) and small number of pulses. In this study, we explored cell death under conditions of reduced EFS and prolonged pulse application, identifying the contributions of electrolysis, reactive oxygen species (ROS) and ATP loss. We performed ablations with conventional high-voltage low pulse (HV-LP) and low-voltage high pulse (LV-HP) conditions in a 3D tumor mimic, finding equivalent ablation volumes when using 2000 V/cm 90 pulses or 1000 V/cm 900 pulses respectively. These results were confirmed by performing ablations in swine liver. In LV-HP treatment, ablation volume was found to increase proportionally with pulse numbers, without the substantial temperature increase seen with HV-LP parameters. Peri-electrode pH changes, ATP loss and ROS production were seen in both conditions, but LV-HP treatments were more sensitive to blocking of these forms of cell injury. Increases in current drawn during HV-LP was not observed during LV-HP condition where the total ablation volume correlated to the charge delivered into the tissue which was greater than HV-LP treatment. LV-HP treatment provides a new paradigm in using pulsed electric fields for tissue ablation with clinically relevant volumes.

Irreversible Electroporation (IRE) for Prostate Cancer (PCa) Treatment: The State of the Art

We evaluated the most recent research from 2000 to 2023 in order to deeply investigate the applications of PCa IRE, first exploring its usage with primary intent and then salvage intent. Finally, we discuss the differences with other focal PCa treatments. In the case of primary-intent IRE, the in-field recurrence is quite low (ranges from 0% to 33%). Urinary continence after the treatment remains high (>86%). Due to several different patients in the studies, the preserved potency varied quite a lot (59-100%). Regarding complications, the highest occurrence rates are for those of Grades I and II (20-77% and 0-29%, respectively). Grade III complications represent less than 7%. Regarding the specific oncological outcomes, both PCa-specific survival and overall survival are 100%. Metastasis-free survival is 99.6%. In a long-term study, the Kaplan-Meier FFS rates reported are 91% at 3 years, 84% at 5 years, and 69% at 8 years. In the single study with salvage-intent IRE, the in-field recurrence was 7%. Urinary continence was still high (93%), but preserved potency was significantly lower than primary-intent IRE patients (23%). In addition, Grade III complications were slightly higher (10.8%). In conclusion, in males with localized low-intermediate-risk prostate cancer, IRE had an excellent safety profile and might have positive results for sexual and urinary function.

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.

Real-World Comparative Safety and Effectiveness of Irreversible Electroporation and High-Intensity Focused Ultrasound for Prostate Cancer Ablation

OBJECTIVES

To assess the comparative safety and effectiveness of 2 prostate cancer treatment ablation modalities: irreversible electroporation (IRE) and high-intensity focused ultrasound (HIFU).  METHODS: Two systematic literature reviews (SLRs) and meta-analyses (MAs) on IRE and HIFU were conducted in accordance with PRISMA guidelines. Searches were conducted in PubMed and EMBASE. Independent reviewers assessed literature eligibility and abstracted safety and effectiveness data. Oncological, safety, functional, and quality of life (QOL) outcomes were examined for each technology. MAs were conducted where data quality and availability allowed, using normal methods and a random/mixed effects model, and quality assessments performed.

RESULTS

Fifty-five publications (n = 22 IRE; n = 33 HIFU) were included in the SLRs, and MAs were conducted on negative in-field post-procedure biopsy, prostate-specific antigen (PSA) level reduction, potency, urinary continence, and AE rate outcomes. MAs revealed that IRE patients had lower mean percent PSA level reductions, higher mean rates of in-field negative post-treatment biopsy, and higher rates of potency maintenance than HIFU patients. Most adverse events (AEs) reported were comparable and minor (Grades I, II), with urinary tract infection, dysuria, hematuria, and incontinence or urgency most frequently reported. The proportion of patients experiencing a severe AE (≥Grade III) ranged from 0 to 8% after IRE and HIFU. Both modalities were associated with positive functional outcomes as well as maintenance of QOL after treatment.

CONCLUSIONS

Both IRE and HIFU were found to produce favorable effectiveness outcomes and have low complication rates while minimally impacting patient urinary and erectile function and maintaining overall QOL. These real-world findings can help guide clinical decision making and improve disease management for patients with prostate cancer.

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.

Genitourinary tumors

Memorial Sloan Kettering Cancer Center (MSK) has made many notable contributions to the scientific understanding and care of patients with common urologic cancers. Many of the advances represented paradigm shifts in management and established new standards of care. This review highlights the surgical procedures and treatment strategies originated and pioneered by urologic surgeons and colleagues at MSK during the past 50 years.

Extended Focal Ablation of Localized Prostate Cancer With High-Frequency Irreversible Electroporation: A Nonrandomized Controlled Trial

IMPORTANCE

Focal therapy of prostate cancer must balance the oncologic outcome and functional outcome. High-frequency irreversible electroporation (H-FIRE) can destroy cancer cells while selectively preserving surrounding nerves and blood vessels, but no clinical trials have been conducted, to our knowledge.

OBJECTIVE

To evaluate the efficacy and safety of H-FIRE in the treatment of localized prostate cancer (PCa).

DESIGN, SETTING, AND PARTICIPANTS

This was a single-group, objective performance criteria, nonrandomized controlled trial. Recruitment began on May 2, 2018, and ended March 27, 2019. The follow-up duration was 6 months. This was a multicenter trial conducted at 4 tertiary teaching hospitals in China. Patients with low or intermediate risk of biochemical recurrence of localized and locally advanced PCa were eligible. Key inclusion criteria were serum prostate-specific antigen (PSA) level less than 20 ng/mL, clinical stage of T2c or less, and Gleason score of 7 or less. Data were analyzed from January 20 to February 20, 2021.

INTERVENTION

H-FIRE ablation of all lesions identified with biopsy.

MAIN OUTCOMES AND MEASURES

The primary end point was 6-month clinically significant PCa (csPCa), which was defined as any biopsy core with Gleason score of greater than or equal to 7, or Gleason score of 6 plus maximum cancer core length of greater than 3 mm or an increase from the original cancer burden. Secondary outcomes were calculated in patients who actually received H-FIRE treatment.

RESULTS

A total of 117 patients (median [IQR] age, 67 [62-73] years) were recruited from 4 centers, and 109 patients (27 [24.8%] low risk and 82 [75.2%] intermediate risk) actually received H-FIRE. Median (IQR) PSA level was 9.0 (6.0-12.7) ng/mL. Among the 100 patients who underwent biopsy at 6 months, the 6-month csPCa rate was 6.0% (95% CI, 2.2%-12.6%; P < .001; 1 in the treatment zone and 5 outside the treatment zone). Superiority criteria vs the historical control of 20% was achieved. PCa was detected in 14 patients, with a Gleason score of 7 in 2 patients and 6 in the remaining 12 patients. At 6 months, median (IQR) PSA level was 1.08 (0.4-3.2) ng/mL, median (IQR) International Prostate Symptom Score was 4.5 (2.0-9.5), and median (IQR) International Index of Erectile Function 5 score was 2.0 (0.5-12.5). Superiority vs the 20% historical control was also met in the subgroup analysis that only included the 57 patients with Gleason score of 7 at baseline (3.5% 6-month csPCa; 95% CI, 0.4%-12.1%).

CONCLUSIONS AND RELEVANCE

The rate of 6-month csPCa with H-FIRE ablation was lower than the historical control using other energy platforms.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03838432.

Detailing Sexual Outcomes After Focal Therapy for Localised Prostate Cancer: A Systematic Review and Meta-analysis

CONTEXT

Focal therapy has emerged as a promising option to treat well-selected men with localised prostate cancer while preserving healthy prostate tissue and key structures, such as the urethral sphincter and neurovascular bundles. However, how this tissue preservation may translate into improved outcomes, particularly into improved sexual outcomes, is still an active research field.

OBJECTIVE

We conducted a systematic review and meta-analysis of the literature to summarise the existing evidence, in order to provide patients with updated data on what to expect after treatment and help identify gaps in current knowledge that may warrant future research.

EVIDENCE ACQUISITION

A systematic literature search was conducted on Medline, EMBASE, Scopus, and Web of Science. The search strategy was defined using the "litsearchr" function in R based on a preliminary "naïve" search using the following terms on Medline: (("focal therapy" OR "focal treatment") AND ("prostate cancer") AND ("sexual function" OR "erectile function")). A total of 42 studies, comprising 3117 patients treated and 2352 with available sexual outcomes, were included in the qualitative data synthesis and 26 in a random-effect meta-analysis.

EVIDENCE SYNTHESIS

The five-item International Index of Erectile Function (IIEF-5) was the most frequently used questionnaire (30/42 studies), with completion rates ranging from 24% to 100% at 18-24 mo. A decrease was noted at 3 mo (IIEF-5 decrease estimate -3.70 [95% confidence interval -4.43, -2.96]), with improvements at 6 mo (-2.18 [-2.91, -1.46]) and 12 mo (-2.14 [-2.96, -1.32]). Studies in which patients had an altered baseline sexual function were more likely to report a significant and durable postoperative decrease in erectile function scores. The patient-reported outcome questionnaires used were not designed for a diverse population. Functional outcomes were not the primary endpoint and have not been reported consistently in most studies considered.

CONCLUSIONS

Focal therapy led to changes in erectile function in most cases under the significance threshold of the patient-reported outcome questionnaires used. However, patients should be counselled according to their baseline erectile function. More research is warranted to detail aspects other than erectile function, such as ejaculation or orgasm. The early postoperative period appears key to study sexual changes after focal therapy, while only a moderate decrease is expected at 12 mo.

PATIENT SUMMARY

We reviewed the published literature detailing the sexual consequences of focal therapy for localised prostate cancer using patient-reported outcome questionnaires. Patients were likely to describe a significant decrease in their erectile function at 3 mo, with improvements noted at 6 and 12 mo. The results obtained may not be reproducible in a more diverse population, and further research is warranted to better study aspects other than erectile function, such as ejaculation or orgasm.

An Updated Systematic Review on Focal Therapy in Localized Prostate Cancer: What Has Changed over the Past 5 Years?

CONTEXT

Focal therapy is a promising, minimally invasive strategy to selectively treat localized prostate cancer. A previous systematic review indicated that there is growing evidence for favorable functional outcomes, but that oncological effectiveness was yet to be defined.

OBJECTIVE

To assess the effectiveness of focal therapy in patients with localized prostate cancer in terms of functional and oncological outcomes.

EVIDENCE ACQUISITION

PubMed, Embase, and The Cochrane Library were searched for studies between October 2015 and December 31, 2020. In addition, the research stages were acquired according to the Idea, Development, Exploration, Assessment, Long-term study (IDEAL) recommendations. Ongoing studies were identified through clinical trial registries.

EVIDENCE SYNTHESIS

Seventy-two studies were identified exploring eight different sources of energy to deliver focal therapy in 5827 patients. Twenty-seven studies reported on high-intensity focused ultrasound (HIFU), nine studies on irreversible electroporation, 11 on cryoablation, eight on focal laser ablation and focal brachytherapy, seven on photodynamic therapy (PDT), two on radiofrequency ablation, and one on prostatic artery embolization. The majority of studies were prospective development stage 2a studies (n = 35). PDT and HIFU, both in stage 3, showed promising results. Overall, HIFU studies reported a median of 95% pad-free patients and a median of 85% patients with no clinically significant cancer (CSC) in the treated area. For PDT, no changes in continence were reported and a median of 90% of patients were without CSC. Both treatments were well tolerated.

CONCLUSIONS

Over the past 5 yr, focal therapy has been studied for eight different energy sources, mostly in single-arm stage 2 studies. Although a first randomized controlled trial in focal therapy has been performed, more high-quality evaluations are needed, preferably via multicenter randomized controlled trials with long-term follow-up and predefined assessment of oncological and functional outcomes and health-related quality-of-life measures.

PATIENT SUMMARY

Focal treatment (FT) of prostate cancer has potential, considering that it has less impact on continence and potency than radical treatment. Our systematic review indicates that despite the method being studied extensively over the past half decade, the majority of studies remain in an early research stage. The techniques high-intensity focused ultrasound and photodynamic therapy have shown most progression toward advanced research stages and show favorable results. However, more high-quality evidence is required before FT can become available as a standard treatment.

Focal therapy for primary and salvage prostate cancer treatment: a narrative review

Despite innovations in surgical technology and advancements in radiation therapy, radical treatments for clinically localized prostate cancer are associated with significant patient morbidity, including both urinary and sexual dysfunction. This has created a vital need for therapies and management strategies that provide an acceptable degree of oncologic efficacy while mitigating these undesirable side effects. Successful developments in screening approaches and advances in prostate imaging have allowed clinicians to identify, localize, and more precisely target early cancers. This has afforded urologists with an important opportunity to develop and employ focal ablation techniques that selectively destroy tumors while preserving the remainder of the gland, thus avoiding detrimental treatment effects to surrounding sensitive structures. A lack of high-level evidence supporting such an approach had previously hindered widespread adoption of focal treatments, but there are now numerous published clinical trials which have sought to establish benchmarks for safety and efficacy. As the clinical evidence supporting a potential role in prostate cancer treatment begins to accumulate, there has been a growing acceptance of focal therapy in the urologic oncology community. In this narrative review article, we describe the techniques, advantages, and side effect profiles of the most commonly utilized focal ablative techniques and analyze published clinical trial data supporting their evolving role in the prostate cancer treatment paradigm.

[MRI-guided minimally invasive treatment of prostate cancer]

CLINICAL/METHODOLOGICAL ISSUE

Multiparametric magnetic resonance imaging (mpMRI) of the prostate plays a crucial role in the diagnosis and local staging of primary prostate cancer.

STANDARD RADIOLOGICAL METHODS

Image-guided biopsy techniques such as MRI-ultrasound fusion not only allow guidance for targeted tissue sampling of index lesions for diagnostic confirmation, but also improve the detection of clinically significant prostate cancer.

METHODOLOGICAL INNOVATIONS

Minimally invasive, focal therapies of localized prostate cancer complement the treatment spectrum, especially for low- and intermediate-risk patients.

PERFORMANCE

In patients of low and intermediate risk, MR-guided, minimally invasive therapies could enable local tumor control, improved functional outcomes and possible subsequent therapy escalation. Further study results related to multimodal approaches and the application of artificial intelligence (AI) by machine and deep learning algorithms will help to leverage the full potential of focal therapies for prostate cancer in the upcoming era of precision medicine.

ACHIEVEMENTS

Completion of ongoing randomized trials comparing each minimally invasive therapy approach with established whole-gland procedures is needed before minimally invasive therapies can be implemented into existing treatment guidelines.

PRACTICAL RECOMMENDATIONS

This review article highlights minimally invasive therapies of prostate cancer and the key role of mpMRI for planning and conducting these therapies.

Irreversible Electroporation for Prostate Cancer

Although it can be lethal in its advanced stage, prostate cancer can be effectively treated when it is localised. Traditionally, radical prostatectomy (RP) or radiotherapy (RT) were used to treat all men with localised prostate cancer; however, this has significant risks of post-treatment side effects. Focal therapy has emerged as a potential form of treatment that can achieve similar oncological outcomes to radical treatment while preserving functional outcomes and decreasing rates of adverse effects. Irreversible electroporation (IRE) is one such form of focal therapy which utilises pulsatile electrical currents to ablate tissue. This modality of treatment is still in an early research phase, with studies showing that IRE is a safe procedure that can offer good short-term oncological outcomes whilst carrying a lower risk of poor functional outcomes. We believe that based on these results, future well-designed clinical trials are warranted to truly assess its efficacy in treating men with localised prostate cancer.

Cryoablation, high-intensity focused ultrasound, irreversible electroporation, and vascular-targeted photodynamic therapy for prostate cancer: a systemic review and meta-analysis

Cryoablation (CA), high-intensity focused ultrasound (HIFU), irreversible electroporation (IRE), and vascular-targeted photodynamic therapy (VTP) have been evaluated as novel strategies for selected patients with prostate cancer (PCa). We aim to determine the current status of literature regarding the clinical outcomes among these minimally invasive therapies. A systematic search of PubMed, EMBASE, and the Cochrane Library for all English literature published from January 2001 to December 2019 was conducted to identify studies evaluating outcomes of CA, HIFU, IRE or VTP on PCa. Proportionality with 95% confidence intervals (CIs) was performed using STATA version 14.0. 56 studies consisting of 7383 participants were found to report data of interest and fulfilled the inclusion criteria in the final meta-analysis. The pooled proportions of positive biopsy after procedure were 20.0%, 24.3%, 24.2%, and 36.2% in CA, HIFU, IRE and VTP, respectively. The pooled proportions of BRFS were 75.7% for CA and 74.4% for HIFU. The pooled proportions of CSS were 96.1%, 98.2%, and 97.9% for CA, HIFU, and IRE, respectively. The pooled proportions of OS were 92.8% for CA and 85.2% for HIFU. The pooled proportions of FFS were 64.7%, 90.4%, and 76.7% for CA, IRE and VTP, respectively. The pooled proportions of MFS were 92.8% for HIFU and 99.1% for IRE. This meta-analysis shows that CA, HIFU, IRE, and VTP are promising therapies for PCa patients with similar clinical outcomes. However, further larger, well-designed randomized controlled trials are required to confirm this assertion.

Feasibility of in-office MRI-targeted partial gland cryoablation for prostate cancer: an IDEAL stage 2A study

OBJECTIVES

Cryoablation for prostate cancer is typically performed under general anaesthesia. We explore the safety, feasibility and costs of in-office MRI-targeted prostate partial gland cryoablation (PGC) under local anaesthesia. We hypothesise that an office-based procedure under local anaesthesia may yield greater patient convenience and lower health costs with similar outcomes to a general anaesthesia approach.

DESIGN/PARTICIPANTS/SETTING/INTERVENTIONS

Retrospective study of men diagnosed with clinically significant prostate cancer (grade group (GG) ≥2) who elected to undergo in-office PGC under local anaesthesia.

MAIN OUTCOME MEASURES

A total of 55 men with GG ≥2 prostate cancer underwent PGC under local anaesthesia, and 35 of 43 men (81.4%) who attained ≥6 months of follow-up post-treatment underwent MRI-targeted surveillance biopsy. We used MRI findings and targeted biopsy to characterise post-PGC oncological outcomes. Complications were categorised using Common Terminology Criteria for Adverse Events (CTCAE). Expanded Prostate Cancer Index-Clinical Practice was used to characterise urinary and sexual function scores at baseline, 4 and 9 months post-PGC. Time-driven activity-based costing was used to determine healthcare costs of in-office PGC.

RESULTS

Five (9.1%) men experienced CTCAE score 3 adverse events. Urinary and sexual function did not change significantly from baseline to 4 months (p=0.20 and p=0.08, respectively) and 9 months (p=0.23 and p=0.67, respectively). Twenty-two men (62.9%) had no cancer or GG1 and 13 (37.1%) men had GG≥2 on post-PGC biopsy. Moreover, the median cost of in-office PGC was US$4,463.05 (range US$4,087.19-US7,238.16) with disposables comprising 69% of the cost.

CONCLUSIONS

In-office PGC is feasible under local anaesthesia with favourable functional outcome preservation and adverse events profile at significantly lower costs compared with a general anaesthesia approach.

Preliminary Diagnostic Accuracy of Multiparametric Magnetic Resonance Imaging to Detect Residual Prostate Cancer Following Focal Therapy with Irreversible Electroporation

BACKGROUND

It is recommended to perform multiparametric magnetic resonance imaging (mpMRI) in the follow-up following focal therapy of prostate cancer (PCa).

OBJECTIVE

To determine the diagnostic accuracy of mpMRI to detect residual PCa following focal therapy with irreversible electroporation.

DESIGN, SETTING, AND PARTICIPANTS

Seventy-six patients with biopsy-proven localized PCa consented for primary irreversible electroporation between February 2013 and March 2016. Final analysis was performed on 50 patients that received follow-up mpMRI at 6 mo, serial prostate-specific antigen (PSA) testing, and transperineal template-mapping biopsies at 12 mo.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Outfield regions of interest (ROI) were reported using PI-RADS version 2. A binary outcome (suspicious vs nonsuspicious) was given for the infield ablation zone. Sensitivity, specificity, positive predictive values, and negative predictive values were calculated for different definitions of significant PCa: (1) Gleason ≥4+3 or Gleason ≥3+3 with a maximum cancer core length ≥6mm, (2) Gleason ≥3+4 or Gleason ≥3+3 with a maximum cancer core length ≥4mm, for outfield and infield ROI. Multivariate linear regression analyses evaluated the additional value of nadir PSA.

RESULTS AND LIMITATIONS

Sensitivity, specificity, positive predictive values, and negative predictive values of infield ROI was 43%, 86%, 33%, and 90% for definition 1 and 38%, 86%, 33%, and 88% for definition 2, respectively. For outfield ROI this was 33%, 82%, 20%, and 90% for definition 1 and 38%, 86%, 50%, and 80% for definition 2. PSA had no additional value in predicting residual significant PCa. Limitations include retrospective design, single reader, and low incidence of residual PCa.

CONCLUSIONS

Our preliminary data suggest that mpMRI can rule out high-volume residual PCa. However, follow-up biopsies should still be performed to determine oncological control.

PATIENT SUMMARY

Multiparametric magnetic resonance imaging is able to detect high-volume significant prostate cancer following focal therapy. Prostate biopsies are still required in the follow-up of focal therapy as (low-volume) significant prostate cancer is being missed by multiparametric magnetic resonance imaging.

Novel Ablation Therapy Using Endoscopic Irreversible Electroporation in the Bile Duct: A Pilot Animal Study

Background/Aims

Irreversible electroporation (IRE) is a relatively new ablation method. However, the application of IRE ablation in the treatment of biliary disease has not been attempted. A minimally invasive approach using endoscopic retrograde cholangiopancreatography (ERCP) can be a novel therapeutic modality for IRE ablation. In this study, we aimed to investigate the feasibility of endoscopic IRE for the biliary tract using an animal model.

Methods

A new catheter-type electrode was developed for endoscopic IRE ablation of the biliary tract. We performed ERCP and endoscopic IRE ablations in the normal common bile duct of Yorkshire pigs. The experimental setting of IRE was 500 V/cm (50 pulses, 100-µs length). The animals were sacrificed after 24 hr, and the ablated bile duct was examined.

Results

Well-demarcated focal color changes were observed on the mucosa of the common bile duct. The depth of change after IRE was confined to the mucosal and submucosal layers. Apoptotic changes in the bile duct were observed only around the IRE ablation area. Immunohistochemistry assay showed cell death in the bile duct along the electrode.

Conclusions

Endoscopic IRE ablation using ERCP was successfully performed in the common bile duct. It can be a potential option for the treatment of biliary tumors.

Focal bipolar radiofrequency ablation for localized prostate cancer: Safety and feasibility

OBJECTIVES

To evaluate the safety and feasibility of focal bipolar radiofrequency ablation in men with localized prostate cancer.

METHODS

A review of 10 patients treated with a novel bipolar radiofrequency ablation probe integrated in a coil design (Encage; Trod Medical, Bradenton, FL, USA) between 2011 and 2017 in two prospective pilot trials. All men had clinical stage T1c prostate cancer, prostate-specific antigen <10 ng/mL and Gleason score ≤7. Ablation was carried out under general anesthesia, and bipolar probes were inserted transperineally under transrectal ultrasound guidance. Treatment-related adverse events, quality of life and negative biopsy rate were evaluated at 6 months after ablation. The Wilcoxon signed-rank test was used to compare baseline and post-treatment symptom scores.

RESULTS

The median age was 58 years (range 50-64 years) and the median prostate volume was 49.65 cc (range 21-68 cc). Prostate cancer with a Gleason score of 6 (3 + 3) and 7 (3 + 4) was noted in seven and three patients, respectively. The median number of radiofrequency ablation cycles was 2.5 (range 2-5). All patients were catheter-free and able to void the day of surgery. Within 6 months after ablation, all adverse events were low grade, with the exception of one grade 3 hematuria that required cystoscopy without coagulation. Six months after ablation bowel, urinary and hormonal functions, and overall satisfaction remained stable. Erectile dysfunction occurred in two out of four patients who had normal sexual function before the procedure. Neither urinary incontinence nor urinary infection was noted.

CONCLUSIONS

This first report on focal bipolar radiofrequency ablation documents a safe and feasible treatment option for selected patients with localized prostate cancer.

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.

Toward a clinical real time tissue ablation technology: combining electroporation and electrolysis (E2)

Background

Percutaneous image-guided tissue ablation (IGA) plays a growing role in the clinical management of solid malignancies. Electroporation is used for IGA in several modalities: irreversible electroporation (IRE), and reversible electroporation with chemotoxic drugs, called electrochemotherapy (ECT). It was shown that the combination of electrolysis and electroporation—E2—affords tissue ablation with greater efficiency, that is, lower voltages, lower energy and shorter procedure times than IRE and without the need for chemotoxic additives as in ECT.

Methods

A new E2 waveform was designed that delivers optimal doses of electroporation and electrolysis in a single waveform. A series of experiments were performed in the liver of pigs to evaluate E2 in the context of clinical applications. The goal was to find initial parameter boundaries in terms of electrical field, pulse duration and charge as well as tissue behavior to enable real time tissue ablation of clinically relevant volumes.

Results

Histological results show that a single several hundred millisecond long E2 waveform can ablate large volume of tissue at relatively low voltages while preserving the integrity of large blood vessels and lumen structures in the ablation zone without the use of chemotoxic drugs or paralyzing drugs during anesthesia. This could translate clinically into much shorter treatment times and ease of use compared to other techniques that are currently applied.

Irreversible Electroporation: Background, Theory, and Review of Recent Developments in Clinical Oncology

Irreversible electroporation (IRE) has established a clinical niche as an alternative to thermal ablation for the eradication of unresectable tumors, particularly those near critical vascular structures. IRE has been used in over 50 independent clinical trials and has shown clinical success when used as a standalone treatment and as a single component within combinatorial treatment paradigms. Recently, many studies evaluating IRE in larger patient cohorts and alongside other novel therapies have been reported. Here, we present the basic principles of reversible electroporation and IRE followed by a review of preclinical and clinical data with a focus on tumors in three organ systems in which IRE has shown great promise: the prostate, pancreas, and liver. Finally, we discuss alternative and future developments, which will likely further advance the use of IRE in the clinic.

Novel focal therapy treatment options for prostate cancer

PURPOSE OF REVIEW

Examine and discuss novel focal therapy treatment options for prostate cancer.

RECENT FINDINGS

With the widespread adoption of mpMRI-guided biopsies for prostate cancer, use of image-guided treatment of prostate cancer has increased. Focal therapies leading to partial gland ablation such as partial prostatectomy, focal laser ablation, irreversible electroporation, vascular targeted photodynamic therapy, and focal radiofrequency ablation have emerged and begun to be properly evaluated. This review covers published phase 1 and 2 trials of each treatment and discusses potential limitations of each modality.

SUMMARY

Focal therapy of prostate cancer is being actively investigated. On the basis of limited published data, the treatments appear to be well tolerated and have an acceptable side effect profile. Importantly, short-term oncologic control has been mixed and there are no long-term outcomes. The acquisition of more data is essential to evaluate these novel technology platforms.

Prostate focal therapy: the rule or exception?

PURPOSE OF REVIEW

Prostate focal therapy has the potential to preserve urinary and sexual function while eliminating clinically significant cancer in a subset of men with low-volume, organ-confined prostate cancer. This systematic review aims to examine current evidence to determine the efficacy and safety of focal therapy for standard clinical application.

RECENT FINDINGS

Focal therapy reduces the rate of cancer progression and conversion to radical therapy in men on active surveillance for prostate cancer. As a strategy, success in focal therapy is heavily dependent on the use of imaging and targeted biopsies. Despite advances in these areas, there remains a small but significant risk of under-detecting clinically significant cancer. Similarly, under-estimation of tumor volume may contribute to infield recurrences and close attention must be paid to the ablation margin. Although long-term oncological outcomes remain lacking, focal therapy has a low complication rate, minimal impact on urinary continence and a moderate impact on erectile function.

SUMMARY

With the appropriate expertise in imaging, targeted biopsy and targeted ablation, focal therapy is a good option in men with low-intermediate risk cancer who are willing to maximize their urinary and sexual function. However, close posttreatment surveillance and the possibility of conversion to whole gland therapy must be accepted.

Image-guided Irreversible Electroporation of Localized Prostate Cancer: Functional and Oncologic Outcomes

Background Irreversible electroporation (IRE) is a nonthermal ablative method based on the formation of nanoscale defects in cell membranes leading to cell death. Clinical experience with the technique for treatment of prostate cancer remains limited. Purpose To evaluate urogenital toxicity and oncologic outcome of MRI-transrectal US fusion-guided IRE of localized prostate cancer. Materials and Methods In this prospective study, men with biopsy-proven, treatment-naive, low- to intermediate-risk prostate cancer (prostate-specific antigen [PSA], ≤15 ng/mL; Gleason score, ≤3 + 4; clinical stage, ≤T2c; lesion size at multiparametric MRI, ≤20 mm) underwent focal MRI/transrectal US fusion-guided IRE between July 2014 and July 2017. Primary end point was the urogenital toxicity profile of focal IRE by using participant-reported questionnaires. Secondary end points were biochemical, histologic, and imaging measures of oncologic control. Analyses were performed by using nonparametric and χ² test statistics. Results Thirty men were included (median age, 65.5 years); mean PSA level was 8.65 ng/mL and mean tumor size was 13.5 mm. One grade III adverse event (urethral stricture) was recorded. The proportion of men with erection sufficient for penetration was 83.3% (25 of 30) at baseline and 79.3% (23 of 29; P > .99) at 12 months. Leak-free and pad-free continence rate was 90% (27 of 30) at baseline and 86.2% (25 of 29; P > .99) at 12 months. Urogenital function remained stable at 12 months according to changes in the modified International Consultation on Incontinence Questionnaire Male Lower Urinary Tract Symptoms, or ICIQ-MLUTS, and the International Index of Erectile Function, or IIEF-5, questionnaires (P = .58 and P = .07, respectively). PSA level decreased from a baseline median value of 8.65 ng/mL (interquartile range, 5-11.4 ng/mL) to 2.35 ng/mL (interquartile range, 1-3.4 ng/mL) at 12 months (P < .001). At 6 months, 28 of 30 participants underwent posttreatment biopsy. The rate of in-field treatment failure was 17.9% (five of 28) as determined with multiparametric prostate MRI and targeted biopsies at 6 months. Conclusion 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. © RSNA, 2019 Online supplemental material is available for this article.

Impact on genitourinary function and quality of life following focal irreversible electroporation of different prostate segments

PURPOSE

We aimed to evaluate the genitourinary function and quality of life (QoL) following the ablation of different prostate segments with irreversible electroporation (IRE) for localized prostate cancer (PCa).

METHODS

Sixty patients who received primary focal IRE for organ-confined PCa were recruited for this study. Patients were evaluated for genitourinary function and QoL per prostate segment treated (anterior vs. posterior, apex vs. base vs. apex-to-base, unilateral vs. bilateral). IRE system settings and patient characteristics were compared between patients with preserved vs. those with impaired erectile function and urinary continence. Data were prospectively collected at baseline, 3, 6, and 12 months using the expanded prostate cancer index composite, American Urological Association symptom score, SF-12 physical and mental component summary surveys. Difference over time within segments per questionnaire was evaluated using the Wilcoxon's signed rank test. Outcome differences between segments were assessed using covariance models. Baseline measurements included questionnaire scores, age, and prostate volume.

RESULTS

There were no statistically significant changes over time for overall urinary (P = 0.07-0.89), bowel (P = 0.06-0.79), physical (P = 0.18-0.71) and mental (P = 0.45-0.94) QoL scores within each segment. Deterioration of sexual function scores was observed at 6 months within each segment (P = 0.001-0.16). There were no statistically significant differences in QoL scores between prostate segments (P = 0.08-0.97). Older patients or those with poor baseline sexual function at time of treatment were associated with a greater risk of developing erectile dysfunction.

CONCLUSION

IRE is a feasible modality for all prostate segments without any significantly different effect on the QoL outcomes. Older patients and those with poor sexual function need to be counseled regarding the risk of erectile dysfunction.

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.

Focal therapy for prostate cancer: concepts and future directions

PURPOSE OF REVIEW

To present a perspective on the current status and future directions of focal therapy for prostate cancer (PCa).

RECENT FINDINGS

Focal therapy for localized PCa is a rapidly evolving field. Various recent concepts - the index lesion driving prognosis, the enhanced detection of clinically significant PCa using multiparametric MRI and targeted biopsy, improved risk-stratification using novel blood/tissue biomarkers, the recognition that reducing radical treatment-related morbidity (along with reducing pathologic progression) is a clinically meaningful end-point - have all led to a growing interest in focal therapy. Novel focal therapy modalities are being investigated, mostly in phase 1 and 2 studies. Recently, level I prospective randomized data comparing partial gland ablation with a standard-of-care treatment became available from one study. Recent developments in imaging, including 7-T MRI, functional imaging, radiomics and contrast-enhanced ultrasound show early promise. We also discuss emerging concepts in patient selection for focal therapy.

SUMMARY

PCa focal therapy has evolved considerably in the recent few years. Overall, these novel focal therapy treatments demonstrate safety and feasibility, low treatment-related toxicity and acceptable short-term and in some cases medium-term oncologic outcomes. As imaging techniques evolve, patient selection, detection of clinically significant PCa and noninvasive assessment of therapeutic efficacy will be further optimized. The aspirational goal of achieving oncologic control while reducing radical treatment-related morbidity will drive further innovation in the field.

Twelve-month prostate volume reduction after MRI-guided transurethral ultrasound ablation of the prostate

PURPOSE

To quantitatively assess 12-month prostate volume (PV) reduction based on T2-weighted MRI and immediate post-treatment contrast-enhanced MRI non-perfused volume (NPV), and to compare measurements with predictions of acute and delayed ablation volumes based on MR-thermometry (MR-t), in a central radiology review of the Phase I clinical trial of MRI-guided transurethral ultrasound ablation (TULSA) in patients with localized prostate cancer.

MATERIALS AND METHODS

Treatment day MRI and 12-month follow-up MRI and biopsy were available for central radiology review in 29 of 30 patients from the published institutional review board-approved, prospective, multi-centre, single-arm Phase I clinical trial of TULSA. Viable PV at 12 months was measured as the remaining PV on T2-weighted MRI, less 12-month NPV, scaled by the fraction of fibrosis in 12-month biopsy cores. Reduction of viable PV was compared to predictions based on the fraction of the prostate covered by the MR-t derived acute thermal ablation volume (ATAV, 55°C isotherm), delayed thermal ablation volume (DTAV, 240 cumulative equivalent minutes at 43°C thermal dose isocontour) and treatment-day NPV. We also report linear and volumetric comparisons between metrics.

RESULTS

After TULSA, the median 12-month reduction in viable PV was 88%. DTAV predicted a reduction of 90%. Treatment day NPV predicted only 53% volume reduction, and underestimated ATAV and DTAV by 36% and 51%.

CONCLUSION

Quantitative volumetry of the TULSA phase I MR and biopsy data identifies DTAV (240 CEM43 thermal dose boundary) as a useful predictor of viable prostate tissue reduction at 12 months. Immediate post-treatment NPV underestimates tissue ablation.

KEY POINTS

• MRI-guided transurethral ultrasound ablation (TULSA) achieved an 88% reduction of viable prostate tissue volume at 12 months, in excellent agreement with expectation from thermal dose calculations. • Non-perfused volume on immediate post-treatment contrast-enhanced MRI represents only 64% of the acute thermal ablation volume (ATAV), and reports only 60% (53% instead of 88% achieved) of the reduction in viable prostate tissue volume at 12 months. • MR-thermometry-based predictions of 12-month prostate volume reduction based on 240 cumulative equivalent minute thermal dose volume are in excellent agreement with reduction in viable prostate tissue volume measured on pre- and 12-month post-treatment T2w-MRI.

"Super-active surveillance": MRI ultrasound fusion biopsy and ablation for less invasive management of prostate cancer

Multiparametric magnetic resonance imaging (mpMRI) of the prostate has allowed clinicians to better visualize and target suspicious lesions during biopsy. Targeted prostate biopsies give a more accurate representation of the true cancer volume and stage so that appropriate treatment or active surveillance can be selected. Advances in technology have led to the development of MRI and ultrasound fusion platforms used for targeted biopsies, monitoring cancer progression, and more recently for the application of focal therapy. Lesions visualized on mpMRI can be targeted for ablation with a variety of energy sources employed under both local and general anesthesia. Focal ablation may offer an alternative option for treating prostate cancer as compared to the well-established interventions of whole-gland radiation or prostatectomy. Focal ablation may also be an option for patients on active surveillance who wish to be even more "active" in their surveillance. In this review, we describe the advancements and development of fusion biopsies, the rationale behind focal therapy, and introduce focal ablative techniques for indolent prostate cancers ("super-active surveillance"), including cryoablation and focal laser ablation (FLA) and the subsequent MRI/biopsy surveillance.

Irreversible electroporation for the treatment of localized prostate cancer: a summary of imaging findings and treatment feedback

PURPOSE

Imaging plays a crucial role in ablative therapies for prostate cancer (PCa). Irreversible electroporation (IRE) is a new treatment modality used for focal treatment of PCa. We aimed to demonstrate what imaging modalities can be used by descriptively reporting contrast-enhanced ultrasonography (CEUS), multiparametric magnetic resonance imaging (mpMRI), and grey-scale transrectal ultrasound (TRUS) results. Furthermore, we aimed to correlate quantitatively the ablation zone seen on mpMRI and CEUS with treatment planning to provide therapy feedback.

METHODS

Imaging data was obtained from two prospective multicenter trials on IRE for localized low- to intermediate-risk PCa. The ablation zone volume (AZV) seen on mpMRI and CEUS was 3D reconstructed to correlate with the planned AZV.

RESULTS

Descriptive examples are provided using mpMRI, TRUS, and CEUS for treatment planning and follow-up after IRE. The mean AZV on T2-weighted imaging 4 weeks following IRE was 12.9 cm3 (standard deviation [SD]=7.0), 5.3 times larger than the planned AZV. Linear regression showed a positive correlation (r=0.76, P = 0.002). For CEUS the mean AZV was 20.7 cm3 (SD=8.7), 8.5 times larger than the planned AZV with a strong positive correlation (r=0.93, P = 0.001). Prostate volume is reduced over time (mean= -27.5%, SD=11.9%) due to ablation zone fibrosis and deformation, illustrated by 3D reconstruction.

CONCLUSION

The role of imaging in conjunction with IRE is of crucial importance to guide clinicians throughout the treatment protocol. CEUS and mpMRI may provide essential treatment feedback by visualizing the ablation zone dimensions and volume.

Irreversible Electroporation for Prostate Cancer as Salvage Treatment Following Prior Radiation and Cryotherapy

Salvage treatment options after localized primary treatment failure of prostate cancer are limited and associated with risk for serious complications. We report on the management details of a 57-year-old African American man treated with partial-gland ablation using irreversible electroporation following local recurrence after brachytherapy and prior salvage cryoablation. Therapeutic and functional outcomes were assessed by conventional means, including serum prostate-specific antigen values and prostate biopsy results.

A comparison of time taken to return to baseline erectile function following focal and whole gland ablative therapies for localized prostate cancer: A systematic review

OBJECTIVES

To systematically review erectile function (EF) outcomes following primary whole gland (WG) and focal ablative therapies for localized prostate cancer to ascertain whether the treatment modality or intended treatment volume affects the time taken to recover baseline EF.

METHOD AND MATERIALS

A systematic review was performed according to the preferred reporting items for systematic review and meta-analysis statement. Inclusion criteria were men with localized prostate cancer treated with primary, ablative therapy. Primary outcome was the return to baseline EF measured with objective, validated symptoms scores. Secondary outcome was use of phosphodiesterase inhibitors or erectile aids. Meta-analysis was not performed owing to heterogenous outcome measures.

RESULTS

Of 222 articles identified in February 2017, 55 studies which reported EF after ablative therapy were identified but only 17 used validated outcome measures and met inclusion criteria. WG cryotherapy was used in 2 studies, WG high-intensity focused ultrasound (HIFU) in 5, focal cryotherapy in 2, focal HIFU in 3, focal phototherapy or laser therapy in 4, vascular-targeted photodynamic therapy in 3, and irreversible electroporation in 2. WG cryotherapy was associated with a significant decline in EF at 6 months with minimal improvement at 36 months. Baseline IIEF-15 of patients undergoing focal HIFU fell 30 points at 1 month but returned to baseline by 6 months. The remaining focal therapies demonstrated minimal or no effect on EF, but the men in these studies had small foci of disease. The review is limited by lack of randomized studies and heterogenous outcome measures.

CONCLUSIONS

Most studies assessing the outcomes of focal therapy on sexual function were not of high quality, used heterogenous outcomes, and had relatively short follow up, highlighting the need for more robustly designed studies using validated patient reported outcome measures  for comparison. However, FT in general resulted in less effect on EF than WG ablation.

Irreversible Electroporation: A Novel Ultrasound-guided Modality for Non-thermal Tumor Ablation

Ultrasound-guided tumor ablation techniques have been proven to be highly effective and minimally invasive in the treatment of many diseases. Traditional approaches to ablation include microwave and radiofrequency techniques, cryotherapy, and high-intensity focused ultrasound. However, these methods are prone to heat-sink effects that can diminish the effectiveness of treatment and damage adjacent structures, such as bile ducts, blood vessels, the gallbladder, or bowel. Irreversible electroporation (IRE) is a non-thermal ablation modality that induces cell apoptosis through the application of high-voltage current. IRE is not limited by many of the limitation which affects conventional tumor ablation techniques, and is particularly useful in treating sensitive areas of the body. The article reviews the basics of ultrasound-guided technology, including its clinical applications and effectiveness in the treatment of tumors.

[Evaluation and results of ablative therapies in prostate cancer]

OBJECTIVE

To perform a state of the art about methods of evaluation and present results in ablative therapies for localized prostate cancer.

METHODS

A review of the scientific literature was performed in Medline database (http://www.ncbi.nlm.nih.gov) and Embase (http://www.embase.com) using different associations of keywords. Publications obtained were selected based on methodology, language and relevance. After selection, 102 articles were analysed.

RESULTS

Analyse the results of ablative therapies is presently difficult considering the heterogeneity of indications, techniques and follow-up. However, results from the most recent and homogeneous studies are encouraging. Oncologically, postoperative biopsies (the most important criteria) are negative (without any tumor cells in the treated area) in 75 to 95%. Functionally, urinary and sexual pre-operative status is spared (or recovered early) in more than 90% of the patients treated. More and more studies underline also the correlation between the results and the technique used considering the volume of the gland and, moreover, the "index lesion" localization.

CONCLUSION

The post-treatment pathological evaluation by biopsies (targeted with MRI or, perhaps in a near future, with innovative ultrasonography) is the corner stone of oncological evaluation of ablative therapies. Ongoing trials will allow to standardize the follow-up and determine the best indication and the best techniques in order to optimize oncological and functional results for each patient treated.

Focal irreversible electroporation as primary treatment for localized prostate cancer

OBJECTIVES

To determine the safety, quality of life (QoL) and short-term oncological outcomes of primary focal irreversible electroporation (IRE) for the treatment of localized prostate cancer (PCa), and to identify potential risk factors for oncological failure.

PATIENTS AND METHODS

Patients who met the consensus guidelines on patient criteria and selection methods for primary focal therapy were eligible for analysis. Focal IRE was performed for organ-confined clinically significant PCa, defined as high-volume disease with Gleason sum score 6 (International Society of Urological Pathology [ISUP] grade 1) or any Gleason sum score of 7 (ISUP grades 2-3). Oncological, adverse event (AE) and QoL outcome data, with a minimum of 6 months' follow-up, were analysed. Patient characteristics and peri-operative treatment variables were compared between patients with and without oncological failure on follow-up biopsy. Wilcoxon's signed rank test, Wilcoxon's rank sum test and the chi-squared test were used to assess statistically significant differences in paired continuous, unpaired continuous and categorical variables respectively.

RESULTS

A total of 63 patients met all eligibility criteria and were included in the final analysis. No high-grade AEs occurred. QoL questionnaire analysis demonstrated no significant change from baseline in physical (P = 0.81), mental (P = 0.48), bowel (P = 0.25) or urinary QoL domains (P = 0.41 and P = 0.25), but there was a mild decrease in the sexual QoL domain (median score 66 at baseline vs 54 at 6 months; P < 0.001). Compared with baseline, a decline of 70% in prostate-specific antigen level (1.8 ng/mL, interquartile range 0.96-4.8 ng/mL) was seen at 6-12 months. A narrow safety margin (P = 0.047) and system errors (P = 0.010) were identified as potential early risk factors for in-field oncological failure. In-field and whole-gland oncological control on follow-up biopsies was 84% (38/45 patients) and 76% (34/45 patients); this increased to 97% (38/39 patients) and 87% (34/39 patients) when patients treated with a narrow safety margin and system errors were excluded.

CONCLUSION

Our data support the safety and feasibility of focal IRE as a primary treatment for localized PCa with effective short-term oncological control in carefully selected men.

New advances in focal therapy for early stage prostate cancer

INTRODUCTION

Prostate focal therapy offers men the opportunity to achieve oncological control while preserving sexual and urinary function. The prerequisites for successful focal therapy are to accurately identify, localize and completely ablate the clinically significant cancer(s) within the prostate. We aim to evaluate the evidence for current and upcoming technologies that could shape the future of prostate cancer focal therapy in the next five years. Areas covered: Current literature on advances in patient selection using imaging, biopsy and biomarkers, ablation techniques and adjuvant treatments for focal therapy are summarized. A literature search of major databases was performed using the search terms 'focal therapy', 'focal ablation', 'partial ablation', 'targeted ablation', 'image guided therapy' and 'prostate cancer'. Expert commentary: Advanced radiological tools such as multiparametric magnetic resonance imaging (mpMRI), multiparametric ultrasound (mpUS), prostate-specific-membrane-antigen positron emission tomography (PSMA-PET) represent a revolution in the ability to understand cancer function and biology. Advances in ablative technologies now provide a menu of modalities that can be rationalized based on lesion location, size and perhaps in the near future, pre-determined resistance to therapy. However, these need to be carefully studied to establish their safety and efficacy parameters. Adjuvant strategies to enhance focal ablation are under development.

Uncertainty Quantification in Irreversible Electroporation Simulations

One recent area of cancer research is irreversible electroporation (IRE). Irreversible electroporation is a minimally invasive procedure where needle electrodes are inserted into the body to ablate tumor cells with electricity. The aim of this paper is to investigate how uncertainty in tissue and tumor conductivity propagate into final ablation predictions used for treatment planning. Two dimensional simulations were performed for a circular tumor surrounded by healthy tissue, and electroporated from two monopolar electrodes. The conductivity values were treated as random variables whose distributions were taken from published literature on the average and standard deviation of liver tissue and liver tumors. Three different Monte Carlo setups were simulated each at three different voltages. Average and standard deviation data was reported for a multitude of electrical field properties experienced by the tumor. Plots showing the variability in the electrical field distribution throughout the tumor are also presented.

Normal Porcine Ureter Retains Lumen Wall Integrity but Not Patency Following Catheter-Directed Irreversible Electroporation: Imaging and Histologic Assessment over 28 Days

PURPOSE

To evaluate the effect of catheter-directed irreversible electroporation (IRE) on the integrity, patency, and function of the normal porcine ureter.

MATERIALS AND METHODS

A catheter-mounted electrode was used to perform fluoroscopy-guided IRE in 8 healthy pigs. Two unilateral ablations (90 pulses at 2,000 V, 100 μs) were performed in each animal in the proximal and distal ureter. Serum creatinine measurements and contrast-enhanced computed tomography imaging were performed at 1, 7, 14, 21, and 28 days after IRE, and findings were compared with baseline values by Student t test. Two animals each were euthanized at 1, 7, 14, and 28 days after IRE for histologic assessment of treatment effects. Quantitative histologic analysis of regeneration and healing of the ureteral wall was graded on a five-point scale.

RESULTS

IRE was successfully performed in all animals. Preservation of ureteral wall integrity was confirmed by the leakage-free passage of contrast medium in the treated ureter of all animals through the observation period. Ureteral strictures and associated renal pelvicaliceal dilation were observed in all animals by study days 7 (P = .005) and 14 (P = .007) and did not resolve by day 28. Urothelial recovery was observed in tissue samples from day 7, with progressive replacement of the tunica muscularis with granulation tissue. Despite extensive scarring of the tunica muscularis, full recovery of the urothelium was observed by day 28.

CONCLUSIONS

The normal porcine ureter retains lumen wall integrity and function following catheter-directed IRE. Scarring of the tunica muscularis in the treated ureter results in stricture formation and reduction of lumen patency.

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.