Diagnostic Accuracy of Multiparametric Magnetic Resonance Imaging to Detect Residual Prostate Cancer Following Irreversible Electroporation-A Multicenter Validation Study

A multi-center international study to evaluate the safety, functional and oncological outcomes of irreversible electroporation for the ablation of prostate cancer

BACKGROUND

Irreversible electroporation (IRE) is a novel technique to treat localized prostate cancer with the aim of achieving oncological control while reducing related side effects. We present the outcomes of localized prostate cancer treated with IRE from a multi-center prospective registry.

METHODS

Men with histologically confirmed prostate cancer were recruited to receive IRE. All the patients were proposed for prostate biopsy at 1-year post-IRE ablation. The functional outcomes were measured by the International Prostate Symptom Score (IPSS) and International Index of Erectile Function (IIEF-5) questionnaires. The safety of IRE was graded by the treatment-related adverse events (AEs) according to the Common Terminology Criteria for Adverse Events (CTCAE).

RESULTS

411 patients were recruited in this study from July 2015 to April 2020. The median follow-up time was 24 months (IQR 15-36). 116 patients underwent repeat prostate biopsy during 12-18 months after IRE. Clinically significant prostate cancer (Gleason ≥ 3 + 4) was detected in 24.1% (28/116) of the patients; any grade prostate cancers were found in 59.5% (69/116) of the patients. The IPSS score increased significantly from 7.1 to 8.2 (p = 0.015) at 3 months but decreased to 6.1 at 6 months (p = 0.017). Afterwards, the IPSS level remained stable during follow-up. The IIEF-5 score decreased at 3 months from 16.0 to 12.1 (p < 0.001) and then maintained equable afterwards. The rate of AEs was 1.8% at 3 months and then dropped to less than 1% at 6 months and remained stable until 48 months after IRE. Major AEs (Grade 3 or above) were rare.

CONCLUSION

For men with localized prostate cancer, IRE could achieve good urinary and sexual function outcomes and a reasonable oncological result. The real-world data are consistent with earlier studies, including recently published randomized controlled studies. The long-term oncological results need further investigation and follow-up.

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.

Median 4-year outcomes of salvage irreversible electroporation for localized radio-recurrent prostate cancer

OBJECTIVES

To evaluate the safety, and short to mid-term oncological and quality-of-life (QoL) outcomes of focal irreversible electroporation (IRE) for radio-recurrent prostate cancer (PCa) at a median follow-up of 4 years.

PATIENTS AND METHODS

This was a single-centre series of men with biopsy-proven radio-recurrent PCa treated with IRE between December 2013 and February 2022, with a minimum follow-up of 6 months. Follow-up included magnetic resonance imaging at 6 months, and standard transperineal saturation template biopsies at 12 months. Further biopsies were guided by suspicion on serial imaging or prostate-specific antigen (PSA) levels. Validated questionnaires were used to measure functional outcomes. Significant local recurrence was defined as any International Society of Urological Pathology (ISUP) score ≥ 2 on biopsies. Progression-free survival was defined as no signs of local or systemic disease on either imaging or template biopsies, or according to the Phoenix criteria for biochemical recurrence.

RESULTS

Final analysis was performed on 74 men with radio-recurrent PCa (median age 69 years, median PSA level 5.4 ng/mL, 76% ISUP score 2/3). The median (range) follow-up was 48 (27-68) months. One rectal fistula occurred, and eight patients developed urethral sloughing that resolved with transurethral resection. Among patients who returned questionnaires (30/74, 41%), 93% (28/30) had preserved urinary continence and 23% (7/30) had sustained erectile function at 12-month follow-up. Local control was achieved in 57 patients (77%), who needed no further treatment. Biopsy diagnosed 41(55%) patients received follow up template biopsies, in-field recurrences occurred in 7% (3/41), and out-field recurrences occurred in 15% of patients (6/41). The metastasis-free survival rate was 91% (67/74), with a median (interquartile range) time to metastases of 8 (5-27) months. The Kaplan-Meier estimated 5-year progression-free survival rate was 60%.

CONCLUSIONS

These short- to mid-term safety, oncological and QoL outcome data endorse results from smaller series and show the ability of salvage focal IRE to safely achieve oncological control in patients with radio-recurrent PCa.

Effect of Focal vs Extended Irreversible Electroporation for the Ablation of Localized Low- or Intermediate-Risk Prostate Cancer on Early Oncological Control: A Randomized Clinical Trial

Importance

Focal ablative irreversible electroporation (IRE) is a therapy that treats only the area of the tumor with the aim of achieving oncological control while reducing treatment-related functional detriment.

Objective

To evaluate the effect of focal vs extended IRE on early oncological control for patients with localized low- and intermediate-risk prostate cancer.

Design, Setting, and Participants

In this randomized clinical trial conducted at 5 centers in Europe, men with localized low- to intermediate-risk prostate cancer were randomized to receive either focal or extended IRE ablation. Data were collected at baseline and at regular intervals after the procedure from June 2015 to January 2020, and data were analyzed from September 2021 to July 2022.

Main Outcomes and Measures

Oncological outcome as indicated by presence of clinically significant prostate cancer (International Society of Urological Pathology grade ≥2) on transperineal template-mapping prostate biopsy at 6 months after IRE. Descriptive measures of results from that biopsy included the number and location of positive cores.

Results

A total of 51 and 55 patients underwent focal and extended IRE, respectively. Median (IQR) age was 64 years (58-67) in the focal ablation group and 64 years (57-68) in the extended ablation group. Median (IQR) follow-up time was 30 months (24-48). Clinically significant prostate cancer was detected in 9 patients (18.8%) in the focal ablation group and 7 patients (13.2%) in the extended ablation group. There was no significant difference in presence of clinically significant prostate cancer between the 2 groups. In the focal ablation group, 17 patients (35.4%) had positive cores outside of the treated area, 3 patients (6.3%) had positive cores in the treated area, and 5 patients (10.4%) had positive cores both in and outside of the treated area. In the extended group, 10 patients (18.9%) had positive cores outside of the treated area, 9 patients (17.0%) had positive cores in the treated area, and 2 patients (3.8%) had positive cores both in and outside of the treated area. Clinically significant cancer was found in the treated area in 5 of 48 patients (10.4%) in the focal ablation group and 5 of 53 patients (9.4%) in the extended ablation group.

Conclusions and Relevance

This study found that focal and extended IRE ablation achieved similar oncological outcomes in men with localized low- or intermediate-risk prostate cancer. Because some patients with intermediate-risk prostate cancer are still candidates for active surveillance, focal therapy may be a promising option for those patients with a high risk of cancer progression.

Trial Registration

ClinicalTrials.gov Identifier: NCT01835977.

Guidelines of guidelines: focal therapy for prostate cancer, is it time for consensus?

OBJECTIVE

To provide a summary and discussion of international guidelines, position statements and consensus statements in relation to focal therapy (FT) for prostate cancer (PCa).

METHODS

The European Association of Urology-European Association of Nuclear Medicine-European Society for Radiotherapy and Oncology-European Society of Urogential Radiology-International Society of Urological Pathology-International Society of Geriatric Oncology and American Urological Association-American Society for Radiation Oncology-Society of Urologic Oncology guidelines were interrogated for recommendations for FT. PubMed and Ovid Medline were searched for consensus statements. Only studies in English since 2015 were included. Reference lists of the included articles were also interrogated and a manual search for studies was also performed.

RESULTS

Our results showed a lack of long-term randomised data for FT. International Urological guidelines emphasised the need for more high-quality clinical trials with robust oncological and toxicity outcomes. Consensus and positions statements were heterogenous.

CONCLUSION

A globally accepted guideline for FT planning, technique and follow-up are still yet to be determined. Well-designed studies with long-term follow-up and robust clinical and toxicity endpoints are needed to improve our understanding of FT and create uniform guidelines to streamline management and follow-up.

Median 5-year outcomes of primary focal irreversible electroporation for localised prostate cancer

OBJECTIVES

To evaluate longer-term oncological and functional outcomes of focal irreversible electroporation (IRE) as primary treatment for localised clinically significant prostate cancer (csPCa) at a median follow-up of 5 years (up to 10 years).

PATIENTS AND METHODS

All patients that underwent focal IRE as primary treatment for localised PCa between February 2013 and August 2021 with a minimum 12 months of follow-up were analysed. Follow-up included 6-month magnetic resonance imaging (MRI) and standardised transperineal saturation template ± targeted biopsies at 12 months, and further biopsies in the case of clinical suspicion on serial imaging and/or prostate-specific antigen (PSA) levels. Failure-free survival (FFS) was defined as no progression to radical treatment or nodal/distant disease. Local recurrence was defined as any International Society of Urological Pathology Grade of ≥2 on biopsy.

RESULTS

A total of 229 patients were analysed with a median (interquartile range [IQR]) follow-up of 60 (40-80) months. The median (IQR) age was 68 (64-74) years, the median (IQR) PSA level was 5.9 (4.1-8.2) ng/mL, and 86% harboured intermediate-risk disease and 7% high-risk disease. In all, 38 patients progressed to radical treatment (17%), at a median (IQR) of 35 (17-53) months after IRE. Kaplan-Meier FFS rates were 91% at 3 years, 84% at 5 years and 69% at 8 years. Metastasis-free survival was 99.6% (228/229), PCa-specific and overall survival were 100% (229/229). Residual csPCa was found in 24% (45/190) during follow-up biopsy and MRI showed a complete ablation in 82% (186/226). Short-term urinary continence was preserved (98%, three of 144 at baseline, 99%, one of 131 at 12 months) and erections sufficient for intercourse decreased by 13% compared to baseline (71% to 58%).

CONCLUSION

Longer-term follow-up confirms our earlier findings that focal IRE provides acceptable local and distant oncological control in selected men with less urinary and sexual toxicity than radical treatment. Long-term follow-up and external validation of these findings, is required to establish this new treatment paradigm as a valid treatment option.