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

Evaluating Diagnostic Accuracy and Inter-reader Agreement of the Prostate Imaging After Focal Ablation Scoring System

Background and objective

Focal therapy (FT) is increasingly recognized as a promising approach for managing localized prostate cancer (PCa), notably reducing treatment-related morbidities. However, post-treatment anatomical changes present significant challenges for surveillance using current imaging techniques. This study aimed to evaluate the inter-reader agreement and efficacy of the Prostate Imaging after Focal Ablation (PI-FAB) scoring system in detecting clinically significant prostate cancer (csPCa) on post-FT multiparametric magnetic resonance imaging (mpMRI).

Methods

A retrospective cohort study was conducted involving patients who underwent primary FT for localized csPCa between 2013 and 2023, followed by post-FT mpMRI and a prostate biopsy. Two expert genitourinary radiologists retrospectively evaluated post-FT mpMRI using PI-FAB. The key measures included inter-reader agreement of PI-FAB scores, assessed by quadratic weighted Cohen's kappa (κ), and the system's efficacy in predicting in-field recurrence of csPCa, with a PI-FAB score cutoff of 3. Additional diagnostic metrics including sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and overall accuracy were also evaluated.

Key findings and limitations

Scans from 38 patients were analyzed, revealing a moderate level of agreement in PI-FAB scoring (κ = 0.56). Both radiologists achieved sensitivity of 93% in detecting csPCa, although specificity, PPVs, NPVs, and accuracy varied.

Conclusions and clinical implications

The PI-FAB scoring system exhibited high sensitivity with moderate inter-reader agreement in detecting in-field recurrence of csPCa. Despite promising results, its low specificity and PPV necessitate further refinement. These findings underscore the need for larger studies to validate the clinical utility of PI-FAB, potentially aiding in standardizing post-treatment surveillance.

Patient summary

Focal therapy has emerged as a promising approach for managing localized prostate cancer, but limitations in current imaging techniques present significant challenges for post-treatment surveillance. The Prostate Imaging after Focal Ablation (PI-FAB) scoring system showed high sensitivity for detecting in-field recurrence of clinically significant prostate cancer. However, its low specificity and positive predictive value necessitate further refinement. Larger, more comprehensive studies are needed to fully validate its clinical utility.

Surveillance one year post focal cryotherapy for clinically significant prostate cancer using mpMRI and PIRADS v2.1: An initial experience from a prospective phase II mandatory biopsy study

Objectives

Multiparametric magnetic resonance imaging (mpMRI) surveillance post focal cryotherapy (FT) of prostate cancer is challenging as post treatment artefacts alter mpMRI findings. In this initial experience, we assessed diagnostic performance of mpMRI in detecting clinically significant prostate cancer (csPCa) after FT.

Materials and methods

This single-centre phase II prospective clinical trial recruited 28 men with localized csPCa for FT between October 2019 and April 2021. 12-months post FT mpMRI were performed prior to biopsy and sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of all mpMRI positive subjects were analysed. Chi square goodness of fit test correlated biopsy positive PIRADS3 (P3) and PIRADS4/5 lesions with histology grade group. One way ANOVA test assessed performance of ADC values in differentiating csPCa, non csPCa and benign lesions.

Results

Sensitivity, specificity, PPV and NPV of mpMRI were 100%, 14.28%, 53.84% and 100% for subjects with histologically proven cancer. Correlation of PIRADS v2.1 scores with histologically proven prostate cancer was statistically significant (p < 0.5). Correlation of P3 lesions with non-csPCa was statistically significant (p < 0.02535). Higher ADC value was associated with benign histology (adjusted odds ratio OR 0.97, 95% confidence interval: 0.94, 0.99) (p = 0.008). Among the malignant lesions, higher ADC value was associated with non-csPCa (adjusted OR: 0.97; 95% CI: 0.95, 0.99) (p = 0.032).

Conclusion

mpMRI is highly sensitive in detecting residual cancer. ADC values and PIRADS scores may be of value in differentiating csPCa from non-csPCa with a potential for risk stratification of men requiring re-biopsy versus non-invasive surveillance of remnant prostate.

First experiences using transurethral ultrasound ablation (TULSA) as a promising focal approach to treat localized prostate cancer: a monocentric study

PURPOSE

To share our experience using transurethral ultrasound ablation (TULSA) treatment for focal therapy of localized prostate cancer (PCa).

MATERIALS AND METHODS

Between 10/2019 and 06/2021 TULSA treatment for localized PCa was performed in 22 men (mean age: 67 ± 7 years, mean initial PSA: 6.8 ± 2.1 ng/ml, ISUP 1 in n = 6, ISUP 2 in n = 14 and 2 patients with recurrence after previous radiotherapy). Patients were selected by an interdisciplinary team, taking clinical parameters, histopathology from targeted or systematic biopsies, mpMRI and patients preferences into consideration. Patients were thoroughly informed about alternative treatment options and that TULSA is an individual treatment approach. High-intensity ultrasound was applied using an ablation device placed in the prostatic urethra. Heat-development within the prostatic tissue was monitored using MR-thermometry. Challenges during the ablation procedure and follow-up of oncologic and functional outcome of at least 12 months after TULSA treatment were documented.

RESULTS

No major adverse events were documented. In the 12 month follow-up period, no significant changes of urinary continence, irritative/obstructive voiding symptoms, bowel irritation or hormonal symptoms were reported according to the Expanded Prostate Cancer Index Composite (EPIC) score. Erectile function was significantly impaired 3-6 months (p < 0.01) and 9-12 months (p < 0.05) after TULSA. PSA values significantly decreased after therapy (2.1 ± 1.8 vs. 6.8 ± 2.1 ng/ml, p < 0.001). PCa recurrence rate was 23% (5/22 patients).

CONCLUSION

Establishment of TULSA in clinical routine was unproblematic, short-term outcome seems to be encouraging. The risk of erectile function impairment requires elaborate information of the patient.

The Association of Tissue Change and Treatment Success During High-intensity Focused Ultrasound Focal Therapy for Prostate Cancer

BACKGROUND

Tissue preservation strategies have been increasingly used for the management of localized prostate cancer. Focal ablation using ultrasound-guided high-intensity focused ultrasound (HIFU) has demonstrated promising short and medium-term oncological outcomes. Advancements in HIFU therapy such as the introduction of tissue change monitoring (TCM) aim to further improve treatment efficacy.

OBJECTIVE

To evaluate the association between intraoperative TCM during HIFU focal therapy for localized prostate cancer and oncological outcomes 12 mo afterward.

DESIGN, SETTING, AND PARTICIPANTS

Seventy consecutive men at a single institution with prostate cancer were prospectively enrolled. Men with prior treatment, metastases, or pelvic radiation were excluded to obtain a final cohort of 55 men.

INTERVENTION

All men underwent HIFU focal therapy followed by magnetic resonance (MR)-fusion biopsy 12 mo later. Tissue change was quantified intraoperatively by measuring the backscatter of ultrasound waves during ablation.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Gleason grade group (GG) ≥2 cancer on postablation biopsy was the primary outcome. Secondary outcomes included GG ≥1 cancer, Prostate Imaging Reporting and Data System (PI-RADS) scores ≥3, and evidence of tissue destruction on post-treatment magnetic resonance imaging (MRI). A Student's t - test analysis was performed to evaluate the mean TCM scores and efficacy of ablation measured by histopathology. Multivariate logistic regression was also performed to identify the odds of residual cancer for each unit increase in the TCM score.

RESULTS AND LIMITATIONS

A lower mean TCM score within the region of the tumor (0.70 vs 0.97, p = 0.02) was associated with the presence of persistent GG ≥2 cancer after HIFU treatment. Adjusting for initial prostate-specific antigen, PI-RADS score, Gleason GG, positive cores, and age, each incremental increase of TCM was associated with an 89% reduction in the odds (odds ratio: 0.11, confidence interval: 0.01-0.97) of having residual GG ≥2 cancer on postablation biopsy. Men with higher mean TCM scores (0.99 vs 0.72, p = 0.02) at the time of treatment were less likely to have abnormal MRI (PI-RADS ≥3) at 12 mo postoperatively. Cases with high TCM scores also had greater tissue destruction measured on MRI and fewer visible lesions on postablation MRI.

CONCLUSIONS

Tissue change measured using TCM values during focal HIFU of the prostate was associated with histopathology and radiological outcomes 12 mo after the procedure.

PATIENT SUMMARY

In this report, we looked at how well ultrasound changes of the prostate during focal high-intensity focused ultrasound (HIFU) therapy for the treatment of prostate cancer predict patient outcomes. We found that greater tissue change measured by the HIFU device was associated with less residual cancer at 1 yr. This tool should be used to ensure optimal ablation of the cancer and may improve focal therapy outcomes in the future.

Patient-reported functional outcomes and oncological control after primary focal cryotherapy for clinically significant prostate cancer: A Phase II mandatory biopsy-monitored study

INTRODUCTION

We report herein the impact of focal therapy (FT) on multi-domain functional outcomes in a Phase II prospective clinical trial (NCT04138914) in focal cryotherapy for clinically significant prostate cancer (csPCa).

METHODS

The primary outcome was the detection of a ≥5 point deterioration in any of the four main expanded prostate index composite (EPIC) functional domains. Pretreatment multiparametric magnetic resonance imaging (mpMRI) and transperineal targeted and systematic saturation biopsy were used to select patients with prostate-specific antigen (PSA)≤20 ng/mL, Gleason grade group (GG) ≤4, mpMRI lesion volume ≤ 3 mL (for a single lesion) or ≤1.5 mL (where two lesions were present). Focal cryotherapy was performed with a minimum 5 mm margin around each target lesion. EPIC scores were obtained at baseline and posttreatment at 1, 3, 6, and 12 months. Mandatory repeat mpMRI and prostate biopsy were performed at 12 months to determine the infield and outfield recurrence.

RESULTS

Twenty-eight patients were recruited. The mean age was 68 years, with PSA of 7.3 ng/mL and PSA density of 0.19 ng/mL2 . No Clavien-Dindo ≥3 complications occurred. Transient worsening of EPIC urinary (mean diff 16.0, p < 0.001, 95% confidence interval [CI]: 8.8-23.6) and sexual function scores (mean diff 11.0, p:0.005, 95% CI: 4.0-17.7) were observed at 1-month posttreatment, with recovery by Month 3. A subgroup who had ablation extending to the neurovascular bundle had a trend to delayed recovery of sexual function to Month 6. At 12-month repeat mpMRI and biopsy, 22 patients (78.6%) had no detectable csPCa. Of the six patients (21.4%) who had csPCa recurrences, four were GG2, one GG3, and one GG4. Four patients underwent repeat FT, one underwent radical prostatectomy, while the remaining one patient with low-volume GG2 cancer opted for active surveillance.

CONCLUSION

FT using cryotherapy was associated with a transient deterioration of urinary and sexual function with resolution at 3 months posttreatment and with reasonable early efficacy in well-selected csPCa patients.

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.

Focal Irreversible Electroporation for Localized Prostate Cancer - Oncological and Safety Outcomes Using mpMRI and Transperineal Biopsy Follow-Up

Introduction

Irreversible electroporation (IRE) technology for prostate cancer (PC) generates consecutive electrical pulses between pairs of electrodes which move through tumorous cells, irreversibly perforate their membranes and eventually lead to cell death, while avoiding tissue thermal effect. The technique is used for primary focal lesions as well as for focal salvage cases. This series reports short term oncological control, quality of life and safety results.

Methods

Retrospective data were collected from 45 consecutive cases of primary (N=38) and salvage (N=7) PC patients treated with IRE. All patients had transperineal MRI/US fusion biopsy and PET-PSMA scan prior to treatment, to verify single lesion. Transperineal Nano-Knife IRE system was used in day-care theatre. Patients had 6 months mpMRI, blood PSA and 1 year confirmatory biopsy following procedure. Quality of life was recorded during the first year.

Results

Median primary subgroup analysis (N=38): age 69 years, initial PSA 5.6 ng/dL, lesion size 0.8 mL and ISUP Group 2 (1-3). Median salvage subgroup analysis (N=7): age 76 years, initial PSA 11.9 ng/dL, lesion size 2.0 mL and ISUP Group 4 (1-5). Median catheter time 5 (3-7) days. No Clavien-Dindo>1 complications were reported nor re-admissions, incontinence, strictures or fistulas. 5% of patients were given PDE-5i drugs. Primary group PSA dropped by 39%, mpMRI clearance in 84%, out-field new lesion in 12%, in-field lesion in 4%. Biopsy at 1 year: 4 patients had out-field clinically significant PC, thus 3 had re-IRE and 1 had radiation therapy. Salvage subgroup MRI clearance was 60%, and 52% remained on active surveillance by 1 year.

Conclusion

IRE treatment for focal PC is safe for primary and salvage cases, if done by a meticulously skilled and trained team, and under strict protocols. The short term oncological results are promising especially for primary lesions. Long term oncological results will be published over time.

Salvage irreversible electroporation for radio-recurrent prostate cancer - the prospective FIRE trial

OBJECTIVES

To prospectively assess the safety, functional- and oncological-outcomes of irreversible electroporation (IRE) as salvage therapy for radio-recurrent focal prostate cancer in a multicenter setting.

PATIENTS AND METHODS

Men with focal recurrent PCa after external beam radiation or brachytherapy without metastatic disease on staging imaging and co-registration between mpMRI and biopsies were prospectively included in this multicenter trial. Adverse events were reported following the Clavien-Dindo classification. Validated questionnaires were used for patient-reported functional outcomes. Follow-up consisted of 3 monthly prostate specific antigen (PSA) levels, a 6-month mpMRI and standardised transperineal template mapping biopsies at 12-months. Thereafter follow-up was guided by MRI and/or PSMA-PET/CT and PSA. Local recurrence was defined as any ISUP score ≥2 on biopsies.

RESULTS

37 patients were analysed with a median (interquartile range (IQR)) follow up of 29 (22-43) months. Median age was 71 (53-83), median PSA was 3.5 ng/mL (2.7-6.1). 28 (75.5%) patients harboured intermediate risk and 9 patients (24.5%) high risk PCa. Seven patients (19%) reported self-limiting urgency, frequency, or hematuria (grade 1-2). Seven patients (19%) developed a grade 3 AE; urethral sludge requiring transurethral resection. At 12 months post treatment 93% of patients remained continent and erectile function sufficient for intercourse deteriorated from 35% to 15% (4/27). Local control was achieved in 29 patients (78%) and 27 patients (73%) were clear of local and systemic disease. Four (11%) patients had local recurrence only. Six (16%) patients developed metastatic disease with a median time to metastasis of 8 months.

CONCLUSION

The FIRE trial shows that salvage IRE after failed radiation therapy for localised PCa is safe with minimal toxicity, and promising functional and oncological outcomes. Salvage IRE can offer a possible solution for notoriously difficult to manage radio recurrent prostate tumours.

Outcomes of salvage radical prostatectomy after initial irreversible electroporation treatment for recurrent prostate cancer

OBJECTIVE

To evaluate: (i) safety, (ii) feasibility, and medium-term (iii) oncological and (iv) functional outcomes of salvage radical prostatectomy (sRP) for recurrent localised prostate cancer (PCa) following initial focal therapy using irreversible electroporation (IRE).

PATIENTS AND METHODS

An international, multicentre and retrospective analysis of prospectively collected data of patients that underwent sRP for recurrent localised PCa after initial primary IRE treatment. Data were reported on (i) surgical complications, (ii) feasibility of sRP reported by surgeons, (iii) time interval between IRE and sRP and pathology results, and (iv) urinary continence, erectile function, and quality of life.

RESULTS

In four participating centres, a total of 39 patients with a median (interquartile range [IQR]) age 64 (60-67) years were identified. No serious adverse events occurred during or following sRP and surgery was deemed feasible without difficulties. The median (IQR) time to recurrence following IRE was 14.3 (9.1-38.8) months. Pathology results showed localised disease in 21 patients (53.8%) and locally-advanced disease in 18 (46.2%). Positive surgical margins (PSMs) were observed in 10 patients (25.6%), of which six (15.4%) had significant PSMs. A persistent detectable prostate-specific antigen level was found in one case after sRP, caused by metastatic disease. One patient had a biochemical recurrence 6 months after sRP. These two cases, together with a PSM case, required additional therapy after sRP. After a median (IQR) follow-up of 17.7 (11.8-26.4) months, urinary continence and erectile function were preserved in 34 (94.4%) and 18 patients (52.9%), respectively, while quality of life remained stable.

CONCLUSIONS

Salvage RP is safe and feasible for patients with recurrent localised PCa following initial IRE treatment. The medium-term oncological and functional outcomes are similar to primary RP. Strict patient selection for focal therapy and standardised follow-up is needed as some patients developed high-grade disease.

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

BACKGROUND

Accurate monitoring following focal treatment of prostate cancer (PCa) is paramount for timely salvage treatment or retreatment.

OBJECTIVE

To evaluate the diagnostic accuracy of multiparametric magnetic resonance imaging (mpMRI) to detect residual PCa in the short-term follow-up of focal treatment with irreversible electroporation (IRE) using transperineal or transrectal template ± targeted biopsies.

DESIGN, SETTING, AND PARTICIPANTS

A retrospective international multicenter study of men with biopsy-proven PCa, treated with focal IRE, and followed by mpMRI (index-test) and template biopsies (reference-test) between February 2013 and January 2021, was conducted.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of mpMRI were calculated for in- and outfield residual disease based on two definitions of significant PCa: University College London (UCL) 1-International Society of Urological Pathology (ISUP) ≥3 or ISUP ≥1 with maximum cancer core length (MCCL) ≥6 mm, and UCL2-ISUP ≥2 or ISUP ≥1 with MCCL ≥4 mm.

RESULTS AND LIMITATIONS

A total of 303 patients from five focal therapy centers were treated with primary IRE. The final analysis was performed on 217 men (median age 67, median prostate-specific antigen 6.2, 81% ISUP 2/3) who underwent both mpMRI and template biopsies. Multiparametric MRI missed 38/57 (67%) positive biopsy locations (UCL1) in 22 patients. Sensitivity, specificity, PPV, and NPV of mpMRI to detect whole gland residual disease (UCL1) were 43.6% (95% confidence interval [CI]: 28-59), 80.9% (95% CI: 75-86), 33.3% (95% CI: 21-47), and 86.7% (95% CI: 81-91), respectively. Based on UCL2, sensitivity, specificity, PPV, and NPV were 35.8% (95% CI: 25-48), 82.0% (95% CI: 75-88), 47.1% (95% CI: 34-61), and 74.1% (95% CI: 67-80), respectively. Limitations are the retrospective nature and short follow-up.

CONCLUSIONS

The diagnostic accuracy of mpMRI to detect residual clinically significant PCa following IRE was low. Follow-up template biopsies should be performed, regardless of mpMRI results.

PATIENT SUMMARY

We investigated the accuracy of magnetic resonance imaging (MRI) to detect residual prostate cancer after treatment with irreversible electroporation. The accuracy of MRI is insufficient, and we emphasize the importance of confirmatory prostate biopsies.

Assessment after focal therapy: what is the latest?

PURPOSE OF REVIEW

To review assessment after focal therapy (FT) in the context of developments from the past two years.

RECENT FINDINGS

With a paucity of high-quality studies, recent findings are primarily reliant on results from institutional-based cohorts and reports of expert consensus. Notably, oncologic treatment failure should be further stratified into recurrence in the in-field or out-of-field ablation zone, and both regions should be surveilled postoperatively. Monitoring primarily consists of periodic evaluations of prostate-specific antigen (PSA) testing and magnetic resonance imaging, with histologic sampling needed to confirm suspicion of recurrence. Recent investigations into PSA derivatives, contrast-enhanced ultrasound, and prostate-specific membrane antigen imaging have shown preliminary promise. Although postablation functional outcomes are generally accepted to be excellent, they are limited by the wide range of patient-reported measures, variability in individual practice, and low questionnaire completion rates.

SUMMARY

There is still a need for high-level, long-term data to inform exact standardized protocols to manage patients after FT. A multifaceted approach is required to surveil patients and identify those at risk of recurrence. Embracing shared responsibility between the patient and clinician to fastidiously monitor the infield and out-of-field ablation zones postoperatively is critical to maximize oncologic outcomes.

Focal prostate cancer therapy in the era of multiparametric MRI: a review of options and outcomes

BACKGROUND

The goal of prostate cancer focal therapy is to achieve oncologic control while reducing the rate of adverse events associated with whole-gland treatments. Numerous focal therapy modalities are currently available with early data demonstrating highly variable rates of cancer control and preservation of sexual/urinary function.

METHODS

All English language clinical trial publications evaluating various focal therapies for localized prostate cancer were reviewed. The literature search was limited to studies from the modern era of MRI-guided treatment, as MRI is hypothesized to improve tumor localization and targeting. Primary outcomes were post-treatment cancer-free rates, in-field/out-of-field recurrence rates, and rates of conversion to radical therapy. Secondary outcomes were related to functional status and adverse events.

RESULTS

Numerous focal therapies were identified with clinical data including high-intensity focused ultrasound, transurethral ultrasound ablation, focal laser ablation, focal cryotherapy, irreversible electroporation, and photodynamic therapy. Recurrence rates among all technologies were low to moderate (0-51%) and rates of freedom from radical treatment were highly variable (46-98%). Rates of erectile dysfunction and incontinence generally ranged from 0 to 44% and 0 to 12%, respectively, with variability between focal therapy modalities. Caution should be exercised when comparing studies as outcomes are strongly associated with patient selection. No individual focal therapy is currently recommended by society guidelines. Randomized controlled trials are ongoing in search of a standard of care.

CONCLUSION

For localized MRI-visible prostate cancer, early clinical trial data demonstrate that focal therapy can provide good to moderate cancer control while having preferable side effect profiles compared to whole-gland treatments. While current studies do not make head-to-head comparisons between technologies, early data suggest a potential for these technologies to provide adequate cancer control in a well-selected patient population. The oncologic outcomes of some focal therapies appear promising; however, longer-term follow-up data are needed to assess the durability of early outcomes.

Salvage robot-assisted radical prostatectomy following focal ablation with irreversible electroporation: feasibility, oncological and functional outcomes

Background

To report the feasibility, oncological and functional outcomes of salvage robot-assisted radical prostatectomy (sRARP) for recurrent prostate cancer (PCa) after irreversible electroporation (IRE).

Methods

This was a retrospective analysis of patients who underwent sRARP by a single high-volume surgeon after IRE treatment in our institution. Surgical complications, oncological and functional outcomes were assessed.

Results

15 patients with at least 12 months follow up were identified out of the 234 men who underwent primary IRE between 2013 and 2019. The median [IQR] age was 68 (62–70) years. The median [IQR] time from focal IRE to sRARP was 42 (21–57) months. There were no rectal, bladder or ureteric injuries. The T-stage was pT2 in 9 (60%) patients and pT3a in 6 (40%) patients. Only one (7%) patient had a positive surgical margin. At a median [IQR] follow up of 22 (16–32) months no patient had a biochemical recurrence (PSA > 0.2). All 15 patients were continent (pad-free) by 6 months and 9 (60%) patients had erections sufficient for intercourse with or without PDE5 inhibitors. No predisposing factors were identified for predicting erectile dysfunction after sRARP.

Conclusions

In patients with recurrent or residual significant PCa after focal IRE ablation it is feasible to obtain good functional and oncological outcomes with sRARP. Our results demonstrate that good outcomes can be achieved with sRARP, when respecting close monitoring post-IRE, good patient selection and surgical experience. The limitations of this study are that it is a small series, with short follow up and a lack of standardised quality of life instruments.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12894-022-00978-w.

Focal therapy for prostate cancer with irreversible electroporation: Oncological and functional results of a single institution study

Purpose

Materials and Methods

Results

Conclusions

Single center retrospective analysis of fifty-two prostate cancer patients with customized MR-guided transurethral ultrasound ablation (TULSA)

OBJECTIVES

MR-guided transurethral ultrasound ablation (TULSA) has primarily been investigated for whole-gland prostate ablation, even though the technology is also well-suited for partial gland treatment. The objectives were to perform a clinical service evaluation of partial to whole-gland TULSA for patients with localized prostate cancer (CaP). TULSA was also evaluated as a combined therapy for a subset of patients presenting with both cancer and concurrent benign prostate hyperplasia (BPH).

SUBJECTS AND METHODS

This retrospective, consecutive clinical service evaluation included men with histopathologically-confirmed CaP who underwent TULSA either as primary or salvage treatment. The planned ablation was dependent on the individual tumor characteristics, concurrent BPH and patient preferences. The Clavien-Dindo classification was used to record complications. Surgeon-assessed functional outcomes were reported. Early treatment success was defined by negative multiparametric MRI (mpMRI) and lack of prostate specific antigen (PSA) recurrence.

RESULTS

Fifty-two consecutive patients (47 treatment-naïve and 5 salvage) were included, with median follow-up of sixteen months and a max of thirty-six months. Baseline median (IQR) age and PSA were 67 years (63-76) and 8.0 ng/ml (5.2-13), respectively. Two Grade IIIa adverse events were observed, with no bowel-related complications. For urinary continence outcomes, 1 patient worsened to 1 pad per day. All patients who were previously potent maintained erectile potency. Of the patient subgroup also seeking treatment for BPH, 83% reported symptom improvement. Median (IQR) PSA nadir after primary treatment was 1.1 ng/ml (0.5-2.1). Early treatment success was 88%. Nine patients underwent a single repeat TULSA.

CONCLUSION

Customized prostate ablation with TULSA offers flexible ablation according to patients' disease characteristics and treatment expectations, providing favorable safety and promising early MRI and PSA results. TULSA is a feasible combination therapy for patients with both cancer and concurrent BPH.

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.

Acceptance, Indications and Chances of Focal Therapy in Localized Prostate Cancer: A Real-World Perspective of Urologists in Germany

Purpose: Focal therapy (FT) became a frequently discussed treatment strategy of localized prostate cancer (PCa), but the acceptance and evaluation of FT by practicing urologists are still unclear. Methods: A 25-item anonymized online questionnaire (SurveyMonkey^®) was compiled by the German Society of Residents in Urology Academics Prostate Cancer Working Group and sent to the members of the German association of Urology. Logistic regression analysis was performed to determine parameters for suggestion FT. Results: Two hundred ten urologists (median age 49 years) participated, from which 72% stated PCa as their main treatment focus. Ninety-nine percent of urologists were aware of and 54% wanted to improve their knowledge about FT. Sixty-five percent do not treat PCa with FT. FT is seen as an alternative to active surveillance and radiotherapy/radical prostatectomy by 66% and 37%, respectively. Regarding FT treatment strategies, 35% and 45% would treat all or all significant PCa foci, respectively, whereas 19% would treat mainly the index foci. Currently, 27% believe that FT will be an option as standard treatment in future, but 48% would not suggest FT to their patients, owing to an absence of evidence and insufficient diagnostic tools for proper patient selection today. Suggesting FT to patients is associated with self-performing FT (odds ratio [OR] 2.88, 95% confidence interval [CI] 1.31-6.31) and believing in FT as a standard treatment in future (OR 9.05, 95% CI 6.68-22.30) (both p < 0.01). Conclusion: FT has currently no wide acceptance in German practicing urologists, mainly attributable to an absence of evidence for FT superiority compared to standard treatments.

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.

Prostate cancer treatment with Irreversible Electroporation (IRE): Safety, efficacy and clinical experience in 471 treatments

Background

Irreversible Electroporation (IRE) is a novel image-guided tissue ablation technology that induces cell death via very short but strong pulsed electric fields. IRE has been shown to have preserving properties towards vessels and nerves and the extracellular matrix. This makes IRE an ideal candidate to treat prostate cancer (PCa) where other treatment modalities frequently unselectively destroy surrounding structures inducing severe side effects like incontinence or impotence. We report the retrospective assessment of 471 IRE treatments in 429 patients of all grades and stages of PCa with 6-year maximum follow-up time.

Material and findings

The patient cohort consisted of low (25), intermediate (88) and high-risk cancers (312). All had multi-parametric magnetic resonance imaging, and 199 men had additional 3D-mapping biopsy for diagnostic work-up prior to IRE. Patients were treated either focally (123), sub-whole-gland (154), whole-gland (134) or for recurrent disease (63) after previous radical prostatectomy, radiation therapy, etc. Adverse effects were mild (19.7%), moderate (3.7%) and severe (1.4%), never life-threatening. Urinary continence was preserved in all cases. IRE-induced erectile dysfunction persisted in 3% of the evaluated cases 12 months post treatment. Mean transient IIEF-5-Score reduction was 33% within 12-month post IRE follow-up and 15% after 12 months. Recurrences within the follow-up period occurred in 10% of the treated men, 23 in or adjacent to the treatment field and 18 outside the treatment field (residuals). Including residuals for worst case analysis, Kaplan Maier estimation on recurrence rate at 5 years resulted in 5.6% (CI95: 1.8–16.93) for Gleason 6, 14.6% (CI95: 8.8–23.7) for Gleason 7 and 39.5% (CI95: 23.5–61.4) for Gleason 8–10.

Conclusion

The results indicate comparable efficacy of IRE to standard radical prostatectomy in terms of 5-year recurrence rates and better preservation of urogenital function, proving the safety and suitability of IRE for PCa treatment. The data also shows that IRE, besides focal therapy of early PCa, can also be used for whole-gland ablations, in patients with recurrent PCa, and as a problem-solver for local tumor control in T4-cancers not amenable to surgery and radiation therapy anymore.

Predicting Gleason Score of Prostate Cancer Patients Using Radiomic Analysis

Purpose: Use of quantitative imaging features and encoding the intra-tumoral heterogeneity from multi-parametric magnetic resonance imaging (mpMRI) for the prediction of Gleason score is gaining attention as a non-invasive biomarker for prostate cancer (PCa). This study tested the hypothesis that radiomic features, extracted from mpMRI, could predict the Gleason score pattern of patients with PCa. Methods: This analysis included T2-weighted (T2-WI) and apparent diffusion coefficient (ADC, computed from diffusion-weighted imaging) scans of 99 PCa patients from The Cancer Imaging Archive (TCIA). A total of 41 radiomic features were calculated from a local tumor sub-volume (i.e., regions of interest) that is determined by a centroid coordinate of PCa volume, grouped based on their Gleason score patterns. Kruskal-Wallis and Spearman's rank correlation tests were used to identify features related to Gleason score groups. Random forest (RF) classifier model was used to predict Gleason score groups and identify the most important signature among the 41 radiomic features. Results: Gleason score groups could be discriminated based on zone size percentage, large zone size emphasis and zone size non-uniformity values (p < 0.05). These features also showed a significant correlation between radiomic features and Gleason score groups with a correlation value of -0.35, 0.32, 0.42 for the large zone size emphasis, zone size non-uniformity and zone size percentage, respectively (corrected p < 0.05). RF classifier model achieved an average of the area under the curves of the receiver operating characteristic (ROC) of 83.40, 72.71, and 77.35% to predict Gleason score groups (G1) = 6; 6 < (G2) < (3 + 4) and (G3) ≥ 4 + 3, respectively. Conclusion: Our results suggest that the radiomic features can be used as a non-invasive biomarker to predict the Gleason score of the PCa patients.