Irreversible Electroporation of the Hepatobiliary System: Current Utilization and Future Avenues.

Liver cancer remains a leading cause of cancer-related deaths worldwide despite numerous advances in treatment. While surgical resection remains the gold standard for curative treatment, it is only possible for a minority of patients. Thermal ablation is an effective option for the treatment of smaller tumors; however, its use is limited to tumors that are not located in proximity to sensitive structures due to the heat sink effect and the potential of thermal damage. Irreversible electroporation (IRE) is a non-thermal ablative modality that can deliver targeted treatment and the effective destruction of tumors that are in close proximity to or even surrounding vascular or biliary ducts with minimal damage to these structures. IRE produces short pulses of high-frequency energy which opens pores in the lipid bilayer of cells leading to apoptosis and cell death. IRE has been utilized clinically for over a decade in the treatment of liver cancers with multiple studies documenting an acceptable safety profile and high efficacy rates.

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

Introduction: Irreversible electroporation (IRE) is a new and promising focal therapy for the treatment of localized prostate cancer. In this systematic review, we summarize the literature on IRE for prostate cancer published over the last decade. Methods: PubMed and EMBASE were searched with the end date of May 2023 to find relevant publications on prostate cancer ablation using IRE. Original studies with focal IRE as the primary curative treatment which reported on functional or oncological outcomes were included. The bibliography of relevant studies was also scanned to identify suitable articles. Results: A total of 14 studies reporting on 899 patients treated with IRE for localized prostate cancer were included. Of all the studies reviewed, 77% reported on recurrence within the zone of ablation, and it ranged from 0% to 38.9% for in-field and 3.6% to 28% for out-of-field recurrence. Although, a standardised follow-up protocol was not followed, all the studies employed serial prostate-specific antigen monitoring, a multiparametric magnetic resonance imaging, and a biopsy (6-12 months post-treatment). Across all the studies, 58% reported that the urinary continence returned to the pretreatment levels and 25% reported a minor decrease in the continence from the baseline at 12-months of follow-up. Erections sufficient for intercourse varied from 44% to 75% at the baseline to 55% to 100% at 12-months of follow-up across all the studies. Conclusion: IRE, as a focal therapy, shows promising results with minimal complications and reasonably effective oncological control, but the data comparing it to the standard of care is still lacking. Future research should focus on randomized definitive comparisons between IRE, radical prostatectomy, and radiation therapy.

Irreversible electroporation for colorectal cancer liver metastasis: a review.

Irreversible electroporation (IRE) ablation is gaining popularity over the last decade as a nonthermal alternative to thermal ablation technologies such as radiofrequency ablation (RFA) and Microwave ablation (MWA). This review serves as a practical guide for applying IRE to colorectal cancer liver metastases (CRLM) for interventional radiologists, oncologists, surgeons, and anesthesiologists. It covers patient selection, procedural technique, anesthesia, imaging, and outcomes.

Consensus Guidelines for the Definition of Time-to-Event End Points in Image-guided Tumor Ablation: Results of the SIO and DATECAN Initiative.

There is currently no consensus regarding preferred clinical outcome measures following image-guided tumor ablation or clear definitions of oncologic end points. This consensus document proposes standardized definitions for a broad range of oncologic outcome measures with recommendations on how to uniformly document, analyze, and report outcomes. The initiative was coordinated by the Society of Interventional Oncology in collaboration with the Definition for the Assessment of Time-to-Event End Points in Cancer Trials, or DATECAN, group. According to predefined criteria, based on experience with clinical trials, an international panel of 62 experts convened. Recommendations were developed using the validated three-step modified Delphi consensus method. Consensus was reached on when to assess outcomes per patient, per session, or per tumor; on starting and ending time and survival time definitions; and on time-to-event end points. Although no consensus was reached on the preferred classification system to report complications, quality of life, and health economics issues, the panel did agree on using the most recent version of a validated patient-reported outcome questionnaire. This article provides a framework of key opinion leader recommendations with the intent to facilitate a clear interpretation of results and standardize worldwide communication. Widespread adoption will improve reproducibility, allow for accurate comparisons, and avoid misinterpretations in the field of interventional oncology research. Published under a CC BY 4.0 license. Online supplemental material is available for this article. See also the editorial by Liddell in this issue.

Multicenter randomized controlled trial and registry study to assess the safety and efficacy of the NanoKnife® system for the ablation of stage 3 pancreatic adenocarcinoma: overview of study protocols.

BACKGROUND: Irreversible electroporation (IRE) is a local ablation technique utilizing high voltage, low energy direct current to create nanopores in cell membrane which disrupt homeostasis and leads to cell death. Previous reports have suggested IRE may have a role in treating borderline resectable and unresectable Stage 3 pancreatic tumors. METHODS: Patients with Stage 3 pancreatic ductal adenocarcinoma (PDAC) will be enrolled in either a randomized, controlled, multicenter trial (RCT) or a multicenter registry study. Subjects enrolled in the RCT must have no evidence of disease progression after 3 months of modified FOLFIRINOX (mFOLFIRINOX) treatment prior to being randomization to either a control or IRE arm. Post-induction and post-IRE treatment for the control and IRE arms, respectively, will be left to the discretion of the treating physician. The RCT will enroll 528 subjects with 264 per arm and include up to 15 sites. All subjects will be followed for at least 24 months or until death. The registry study will include two cohorts of patients with Stage 3 PDAC, patients who received institutional standard of care (SOC) alone and those treated with IRE in addition to SOC. Both cohorts will be required to have undergone at least 3 months of SOC without progression prior to enrollment. The registry study will enroll 532 patients with 266 patients in each arm. All patients will be followed for at least 24 months or until death. The primary efficacy endpoint for both studies will be overall survival (OS). Co-primary safety endpoints will be 1) time from randomization or enrollment in the registry to death or new onset of Grade 4 adverse event (AE), and (2 high-grade complications defined as any AE or serious AE (SAE) with a CTCAE v5.0 grade of 3 or higher. Secondary endpoints will include progression-free survival, cancer-related pain, quality of life, and procedure-related pain for the IRE arm only. DISCUSSION: These studies are intended to provide Level 1 clinical evidence and real-world data demonstrating the clinical utility and safety of the use of IRE in combination with chemotherapy in patients with Stage 3 PDAC. TRIAL REGISTRATION: Clinicaltrials.gov NCT03899636 and NCT03899649. Registered April 2, 2019. Food and Drug Administration (FDA) Investigational Device Exemption (IDE) trial G180278 approved on May 3, 2019.

Irreversible Electroporation for Hepatic Tumors: Protocol Standardization Using the Modified Delphi Technique.

PURPOSE: A consensus study of panelists was performed to provide a uniform protocol regarding (contra) indications, procedural parameters, perioperative care, and follow-up of irreversible electroporation (IRE) for the treatment of hepatic malignancies. MATERIALS AND METHODS: Interventional radiologists who had 2 or more publications on IRE, reporting at least 1 patient cohort in the field of hepatobiliary IRE, were recruited. The 8 panelists were asked to anonymously complete 3 iterative rounds of IRE-focused questionnaires to collect data according to a modified Delphi technique. Consensus was defined as having reached 80% or greater agreement. RESULTS: Panel members' response rates were 88%, 75%, and 88% in rounds 1, 2, and 3, respectively; consensus was reached on 124 of 136 items (91%). Percutaneous or intraoperative hepatic IRE should be considered for unresectable primary and secondary malignancies that are truly unsuitable for thermal ablation because of proximity to critical structures. Absolute contraindications are ventricular arrhythmias, cardiac stimulation devices, and congestive heart failure of New York Heart Association class 3 or higher. A metal stent outside the ablation zone should not be considered a contraindication. For the only commercially available IRE device, the recommended settings are an inter-electrode distance of 10-20 mm and an exposure length of 20 mm. After 10 test pulses, 90 treatment pulses of 1500 V/cm should be delivered continuously, with a pulse length of 70-90 µs. The first post-procedural follow-up should take place 1 month after IRE and thereafter every 3 months, using cross-sectional imaging plus tumor marker assessment. CONCLUSIONS: This article provides recommendations, created by a modified Delphi consensus study, regarding patient selection, workup, procedure, and follow-up of IRE treatment for hepatic malignancies.

Role of Urodynamic Studies in Management of Benign Prostatic Obstruction: A Guide for Interventional Radiologists.

Urodynamic testing is the most accurate representation of bladder outlet obstruction physiology. As prostate artery embolization becomes an increasingly common therapy for benign prostatic obstruction, knowledge of urodynamic assessment and reports can assist the interventional radiologist in selecting appropriate patients. This review summarizes the role of urodynamic studies in the management of benign prostatic obstruction, including patient selection, interpretation of urodynamic studies, and their potential to predict patient outcomes.

Prostate Artery Embolization via Transradial or Transulnar versus Transfemoral Arterial Access: Technical Results.

PURPOSE: To compare safety and feasibility of prostate artery embolization (PAE) via transradial/transulnar access (TR/UA) and transfemoral access (TFA). MATERIALS AND METHODS: A retrospective analysis was conducted for 3 cohorts: the first 32 consecutive PAE procedures performed via TFA (initial TFA, January 2014 to August 2015), the following 32 procedures performed via TFA (advanced TFA, August 2015 to February 2016), and the first 32 procedures performed via TR/UA (February 2016 to July 2016). Indications included lower urinary tract symptoms (n = 68), urinary retention (n = 24), and preoperative embolization before prostatectomy (n = 4). A single operator performed all procedures at a single institution. RESULTS: Technical success was achieved in 29/32 (90.6%) initial TFA procedures, 31/32 (96.9%) advanced TFA procedures, and 30/32 (93.8%) TR/UA procedures. Mean procedure time was 110.0 minutes in TR/UA group, 155.1 min in initial TFA group, and 131.3 minutes in advanced TFA group (P < .01 and P = .03 relative to TR/UA); mean fluoroscopy time was 38.8 minutes in TR/UA group, 56.5 minutes in initial TFA group, and 48.0 minutes in advanced TFA group (P < .01 and P = .02 relative to TR/UA). Access site-related and overall adverse events did not vary significantly among study cohorts (P > .15 and P > .05, respectively). CONCLUSIONS: TR/UA represents a safe and feasible approach to PAE with a comparable safety profile to TFA. Reduced procedure and fluoroscopy times might be attributable to the learning curve or method of arterial access.

Role of Coil Embolization during Prostatic Artery Embolization: Incidence, Indications, and Safety Profile☆.

PURPOSE: To determine if coil embolization is a safe adjunctive measure to prevent nontarget embolization during prostatic artery embolization (PAE). MATERIALS AND METHODS: A retrospective analysis of patients who underwent PAE with coil embolization (cPAE) or without coil embolization (nPAE) between January 2014 and June 2016 was conducted. Adverse events, identified in accordance with SIR guidelines, and procedural variables were compared between the 2 cohorts. RESULTS: Of 122 patients, 32 (26.2%) underwent coil embolization in 39 arteries, with coils placed to prevent nontarget embolization (n = 36), treat prostatic artery extravasation (n = 2), and occlude an intraprostatic arteriovenous fistula (n = 1). Compared with nPAE, cPAE had a nonsignificant increase in dose area product (64,516 µGy·m2 vs 52,100 µGy·m2, P = .053) but significantly longer procedure (160.1 min vs 137.1 min, P = .022) and fluoroscopy (62.9 min vs 46.1 min, P = .023) times. One major complication (urosepsis) occurred in each group (cPAE, 1/32 [3.1%]; nPAE, 1/80 [1.3%]). Both cases resolved after 2 weeks of intravenous antibiotics. A minor ischemic complication (1/32 [3.1%]) occurred in a patient with coil embolization, which manifested as white discoloration of the glans penis and resolved with topical therapy. There were no statistically significant differences in major and minor complications between cohorts at 1-month and 3-month follow-up visits. CONCLUSIONS: Although coil embolization leads to increases in procedure and fluoroscopy times, it is a safe adjunctive technique to occlude communications between the prostatic artery and pelvic vasculature to potentially prevent nontarget embolization.

Percutaneous Image-Guided Irreversible Electroporation for the Treatment of Unresectable, Locally Advanced Pancreatic Adenocarcinoma.

PURPOSE: To describe safety and effectiveness of percutaneous irreversible electroporation (IRE) for treatment of unresectable, locally advanced pancreatic adenocarcinoma (LAPC). MATERIALS AND METHODS: This retrospective study included 50 patients (23 women, 27 men; age range, 46-91 y; median age, 62.5 y) with biopsy-proven, unresectable LAPC who received percutaneous computed tomography (CT)-guided IRE. The primary objective was to assess the safety profile of the procedure; the secondary objective was to determine overall survival (OS). All patients had prior chemotherapy (1-5 lines, median 2), and 30 (60%) of 50 patients had prior radiation therapy. Follow-up included CT at 1 month and at 3-month intervals thereafter. RESULTS: There were no treatment-related deaths and no 30-day mortality. Serious adverse events occurred in 10 (20%) of 50 patients (abdominal pain [n = 7], pancreatitis [n = 1], sepsis [n = 1], gastric leak [n = 1]). Median OS was 27.0 months (95% confidence interval [CI], 22.7-32.5 months) from time of diagnosis and 14.2 months (95% CI, 9.7-16.2 months) from time of IRE. Patients with tumors ≤ 3 cm (n = 24) had significantly longer median OS than patients with tumors > 3 cm (n = 26): 33.8 vs 22.7 months from time of diagnosis (P = .002) and 16.2 vs 9.9 months from time of IRE (P = .031). Tumor size was confirmed as the only independent predictor of OS at multivariate analysis. CONCLUSIONS: Percutaneous image-guided IRE of unresectable LAPC is associated with an acceptable safety profile.

Endovascular Coil Embolization in the Treatment of a Rare Case of Post-Traumatic Abdominal Aortic Pseudoaneurysms: Brief Report and Review of Literature.

Traumatic aortic injury, a consequence of penetrating injuries or blunt trauma, is a life threatening condition which requires prompt diagnosis and management. Most abdominal aortic injuries have been repaired via an open surgical approach with endovascular stent graft as an alternative. Traumatic pseudoaneurysms (PSA) of the abdominal aorta are uncommon, and they are managed similar to other abdominal aortic injuries. However, the presence of a perianeurysmal hematoma and the potential risk of an associated concomitant bowel communication could make surgery and endovascular stent graft placement risky. In such patients, coil embolization could be a valued option. In this article, we present a case in which traumatic PSAs are repaired using coil embolization with technical and clinical success. Endovascular coil embolization could be an alternative approach for PSAs that cannot be treated by stent grafting or open surgical repair, in the appropriate anatomy and by using the right coil material and technique.

Irreversible Electroporation (IRE) in Renal Tumors.

Small renal masses (SRMs) have been traditionally managed with surgical resection. Minimally invasive nephron-sparing treatment methods are preferred to avoid harmful consequences of renal insufficiency, with partial nephrectomy (PN) considered the gold standard. With increase in the incidence of the SRMs and evolution of ablative technologies, percutaneous ablation is now considered a viable treatment alternative to surgical resection with comparable oncologic outcomes and better nephron-sparing property. Traditional thermal ablative techniques suffer from unique set of challenges in treating tumors near vessels or critical structures. Irreversible electroporation (IRE), with its non-thermal nature and connective tissue-sparing properties, has shown utility where traditional ablative techniques face challenges. This review presents the role of IRE in renal tumors based on the most relevant published literature on the IRE technology, animal studies, and human experience.

Full dose neoadjuvant FOLFIRINOX is associated with prolonged survival in patients with locally advanced pancreatic adenocarcinoma.

BACKGROUND: The efficacy of FOLFIRINOX for metastatic pancreatic cancer has led to its use in patients with earlier stages of disease. This study retrospectively analyzed a cohort of patients with locally-advanced pancreatic cancer (LAPC) treated with FOLFIRINOX. METHODS: Between 2008 and 2013, 51 treatment-naïve patients with LAPC at a single institution received first-line FOLFIRINOX with neoadjuvant intent, at the full dose as described in the PRODIGE 4/ACCORD 11 study. Combined chemoradiation was administered for those who remained unresectable after maximum response to chemotherapy. The primary outcome measure was overall survival (OS), and secondary outcomes were progression-free survival (PFS) and margin-negative (R0) resection rate, and toxicity profile. RESULTS: A total of 429 cycles of FOLFIRINOX were given with a median of 8 cycles (range 2-29) per patient; 66% of cycles were full dose. After chemotherapy, 27 (53%) received chemoradiation. The median OS was 35.4 months (95% CI 25.8-45). Ten (4 borderline resectable and 6 unresectable) patients had successful R0 resections; those who had R0 resections had a significantly longer survival than those who did not (3-year OS rate 67% versus 21%, log rank p = 0.042). Increasing number of full-dose cycles was significantly associated with increased survival. The toxicity profile was similar to previous reports of this regimen. CONCLUSIONS: FOLFIRINOX is feasible as neoadjuvant therapy for LAPC. Although the R0 resection rate was only 20%, the median OS of almost 3 years appears promising. Dose intensity and duration were associated with increased survival in this study, arguing against dose attenuated versions of this regimen.

Proximal Splenic Artery Embolization in Chemotherapy-Induced Thrombocytopenia: A Retrospective Analysis of 13 Patients.

PURPOSE: To determine if proximal splenic artery embolization (PSAE) provides a safe and effective alternative to alleviate chemotherapy-induced thrombocytopenia (CIT), allowing patients with cancer to resume chemotherapy regimens. MATERIALS AND METHODS: Thirteen patients (9 men, 4 women; mean age, 63 y) with underlying malignancy (pancreatic adenocarcinoma, n = 6; cholangiocarcinoma, n = 5; other, n = 2) complicated by CIT underwent PSAE. Mean platelet counts were calculated before the initiation of chemotherapy, at the nadir that resulted in discontinuation of chemotherapy before the PSAE procedure, at peak values after the procedure, and at a mean follow-up of 9.2 months. The time to reinitiation of chemotherapy after PSAE was calculated. RESULTS: Baseline platelet count before initiation of chemotherapy was 162 × 10(9)/L (range, 90-272 × 10(9)/L). The platelet count nadir resulting in cessation of chemotherapy was 45 × 10(9)/L (range, 23-67 × 10(9)/L), and the pre-PSAE platelet count was 88 × 10(9)/L (range, 49-131 × 10(9)/L). The post-PSAE peak platelet count improved significantly (to 209 × 10(9)/L; range, 83-363 × 10(9)/L) compared with the nadir counts and the pre-PSAE counts (P < .01) at a mean short-term follow-up of 35 days (range, 7-91 d). The counts at follow-up to 9.2 months (range, 3-15 mo) were 152 × 10(9)/L (range, 91-241 × 10(9)/L). All patients became eligible to resume chemotherapy. The time to initiation of chemotherapy after PSAE averaged 22 days (range, 4-58 d) in 12 patients; one patient declined chemotherapy. CONCLUSIONS: Proximal splenic artery embolization appears to be safe and effective in alleviating CIT, allowing resumption of systemic chemotherapy. Further studies may help guide patient selection by identifying characteristics that allow a sustained improvement in thrombocytopenia.

Single-center experience in prostate fiducial marker placement: technique and midterm follow-up.

PURPOSE: To describe the technique, technical success, and complications of prostate fiducial marker implantation using transrectal ultrasound (US) guidance in patients undergoing image-guided radiation therapy. MATERIALS AND METHODS: A retrospective review was performed of patients who underwent fiducial marker placement from January 2010-April 2013. In each case, gold markers were placed in the prostate using transrectal US guidance. Computed tomography (CT) was performed after the procedure and evaluated to confirm correct placement. Technical success, complications, and development of symptoms during radiotherapy were reviewed. RESULTS: Transrectal US-guided fiducial marker placement was performed on 75 patients (mean age, 62 y; range, 48-79 y) with a mean Gleason score of 7.25 (range, 6-10). Fiducial marker placement was confirmed in the intended location of the prostate or prostate bed for 297 of 300 markers (99%) on follow-up CT imaging. Two markers were placed just outside the prostate capsule, and one marker was lost. Complications included sepsis (n = 1; 1.3%), self-limiting perirectal or intraprostatic hemorrhage (n = 3; 4%), nausea (n = 1; 1.3%), transient hypotension (n = 1; 1.3%), epididymitis (n = 1; 1.3%), and urinary tract infection (n = 1; 1.3%). Complications were seen more frequently in patients with high tumor grade (P = .001) and in patients who developed metastatic disease (P = .01). CONCLUSIONS: Transrectal US-guided implantation of fiducial markers is technically feasible, is well tolerated, and has a good safety profile.

Transarterial treatment of colorectal cancer liver metastases with irinotecan-loaded drug-eluting beads: technical recommendations.

Transcatheter hepatic arterial administration of irinotecan-loaded drug-eluting beads (DEBIRI) is used to treat liver-only or liver-dominant metastatic disease from colorectal cancer (CRC). Eligibility for DEBIRI should be established in each individual patient by a multidisciplinary team based on comprehensive clinical, imaging, and laboratory assessment. Standardization of DEBIRI technique and protocols would be expected to lead to improved efficacy and safety. The present article provides a set of technical recommendations for the use of DEBIRI in the treatment of hepatic CRC metastases.

Percutaneous irreversible electroporation for the treatment of colorectal cancer liver metastases with a proposal for a new response evaluation system.

PURPOSE: To describe an initial experience with irreversible electroporation (IRE) in patients with colorectal liver metastasis (CLM). MATERIALS AND METHODS: A retrospective analysis of patients undergoing IRE for the management of CLM was performed. Procedures were done percutaneously under general anesthesia. Patients were then followed for adverse events, tumor response, and survival. RESULTS: Between March 2010 and February 2013, 29 patients underwent percutaneous ablation of 58 tumors in 36 IRE sessions. Most patients (89%) had an absolute or relative contraindication to thermal ablation. The median age was 62 years, and the median time from diagnosis to IRE was 28 months. The median number of lesions treated per patient was two, and the median tumor size was 2.7 cm. Patients had received previous chemotherapy regimens (range, 1-5 per patient). A new Metabolic Imaging And Marker Integration response evaluation criteria was used for response assessment, and was a predictor of progression-free and overall survival. The 2-year progression-free survival rate was 18% (95% confidence interval, 0%-35%), and the 2-year overall survival rate was 62% (95% confidence interval, 37%-87%). Complications included arrhythmias (n = 1) and postprocedure pain (n = 1). Both patients recovered without sequelae. CONCLUSIONS: Percutaneous IRE of CLM is feasible and safe. A new response evaluation system for colorectal cancer appears to be prognostic.

Safety and Effectiveness of Irreversible Electroporation in Lymph Node Metastases.

PURPOSE: Demonstrating the safety and efficacy of percutaneous irreversible electroporation (IRE) for the treatment of lymph node metastases. MATERIALS AND METHODS: An IRB-approved, single-center retrospective review was performed on patients with lymph node metastases gastrointestinal, and genitourinary primary cancers. Primary objective safety was evaluated by assessing complications graded according to the Clavien-Dindo Classification, and efficacy was determined by tumor response on follow-up imaging and local progression-free survival (LPFS). Secondary outcome measures were technical success (complete ablation with an adequate ablative margin > 5 mm), length of hospital stay and distant progression-free survival (DPFS). RESULTS: Nineteen patients underwent percutaneous IRE between June 2018 and February 2023 for lymph node metastases, close to critical structures, such as vasculature, bowel, or nerves. The technical success was achieved in all cases. Complications occurred in four patients (21.1%), including two self-limiting grade 1 hematomas, a grade 1 abdominal pain, and grade 2 nerve pain treated with medication. Seventeen patients were hospitalized overnight, one patient stayed two nights and another patient stayed fourteen nights. Median follow-up was 25.5 months. Median time to local progression was 24.1 months (95% CI: 0-52.8) with 1-, 2-, and 5-year LPFS of 57.9%, 57.9% and 20.7%, respectively. Median time to distant progression was 4.3 months (95% CI: 0.3-8.3) with 1-, 2-, and 5-year DPFS of 31.6%, 13.2% and 13.2%, respectively. CONCLUSION: IRE is a safe and effective minimally-invasive treatment for lymph node metastases in locations, where temperature dependent ablation may be contraindicated. Care should be taken when employing IRE near nerves.

Irreversible Electroporation as a Valid Treatment Option for Hepatic Epithelioid Hemangioendothelioma: An International Multicenter Experience.

PURPOSE: Hepatic epithelioid hemangioendothelioma (HEHE) is a rare tumor with currently no established standard of care. This international multicenter retrospective study assesses the use of percutaneous irreversible electroporation (IRE) as an ablative tool to treat HEHE and provides a clinical overview of the current management and role of IRE in HEHE treatment. MATERIAL AND METHODS: Between 2017 and 2023, 14 patients with 47 HEHE tumors were treated with percutaneous IRE using CT-scan guidance in 23 procedures. Baseline patient and tumor characteristics were evaluated. Primary outcome measures included safety and effectiveness, analyzed using Common Terminology Criteria for Adverse Events (CTCAE) and treatment response by mRECIST criteria. Secondary outcome measures included technical success, post-treatment tumor sizes and length of hospital stay. Technical success was defined as complete ablation with an adequate ablative margin (intentional tumor free ablation margin > 5 mm). RESULTS: IRE treatment resulted in technical success in all tumors. Following a median follow-up of 15 months, 30 tumors demonstrated a complete response according to mRECIST criteria. The average tumor size pre-treatment was 25.8 mm, accompanied by an average reduction in tumor size by 7.5 mm. In 38 out of 47 tumors, there was no evidence of local recurrence. In nine tumors, residual tumor was present. There were no cases of progressive disease. Median length of hospital stay was one day. Only one grade 3 CTCAE event occurred, a pneumothorax requiring chest tube placement. CONCLUSION: The current study provides evidence that IRE is a safe and efficacious minimally invasive treatment option for HEHE.

Safety and early efficacy of irreversible electroporation for hepatic tumors in proximity to vital structures.

INTRODUCTION: Irreversible electroporation (IRE) has shown promise for ablation of lesions in proximity to vital structures in the preclinical setting. This study aims to evaluate the safety and efficacy of IRE for hepatic tumors in the clinical setting. METHODS: An IRB approved prospective registry of patients undergoing IRE for hepatic tumors over a 2-year period. Factors analyzed included patient and tumor characteristics, treatment related complications, and local recurrence free survival (LRFS) for ablated lesions. LRFS was calculated according to Kaplan-Meier, with secondary analyses stratified by procedural approach (laparotomy, laparoscopy, and percutaneous) and tumor histology. RESULTS: There were 44 patients undergoing 48 total IRE procedures, 20 colorectal mets, 14 hepatocellular, and 10 other metastatsis. Initial success was achieved in 46 (100%) treatments. Five patients had 9 adverse events, with all complications resolving within 30 days. LRFS at 3, 6, and 12 months was 97.4%, 94.6%, and 59.5%. There was a trend toward higher recurrence rates for tumors over 4 cm (HR 3.236, 95% CI: 0.585-17.891; P = 0.178). CONCLUSIONS: IRE appears to be a safe treatment for hepatic tumors in proximity to vital structures. Further prospective evaluation is needed to determine the optimal effectiveness of IRE in relation to size and technique for IRE of the liver.