A Single-institution Experience with Open Irreversible Electroporation for Locally Advanced Pancreatic Carcinoma

Process Analysis and Parameter Selection of Cardiomyocyte Electroporation Based on the Finite Element Method

PURPOSE

Pulsed-field ablation (PFA) has attracted attention for the treatment of atrial fibrillation. This study aimed to further explore the relationship between the transmembrane voltage, pore radius and the intensity and duration of pulsed electric fields, which are closely related to the formation of irreversible electroporation. The different mechanisms of microsecond and nanosecond pulses acting on cardiomyocyte cellular and nuclear membranes were studied.

METHODS

A 3-D cardiomyocyte model with a nucleus was constructed to simulate the process of electroporation in cells under an electric field. Cell membrane electroporation was used to simulate the effect of different pulse parameters on the process of electroporation.

RESULTS

Under a single pulse with a field strength of 1 kV/cm and width of 100 μs, the transmembrane potential (TMP) of the cell membrane reached 1.33 V, and the pore density and conductivity increased rapidly. The maximum pore radius of the cell membrane was 43.4 nm, and the electroporation area accounted for 4.6% of the total cell membrane area. The number of pores was positively correlated with the electric field intensity when the cell was exposed to electric fields of 0.5 to 6 kV/cm. Under a nanosecond pulse, the TMP of the nuclear and cell membranes exceeded 1 V after exposure to electric fields with strengths of 4 and 5 kV/cm, respectively.

CONCLUSION

This study simulated the electroporation process of cardiomyocyte, and provides a basis for the selection of parameters for the application of PFA for application toward arrhythmias.

Atrioesophageal Fistula Rates Before and After Adoption of Active Esophageal Cooling During Atrial Fibrillation Ablation

BACKGROUND

Active esophageal cooling reduces the incidence of endoscopically identified severe esophageal lesions during radiofrequency (RF) catheter ablation of the left atrium for the treatment of atrial fibrillation. A formal analysis of the atrioesophageal fistula (AEF) rate with active esophageal cooling has not previously been performed.

OBJECTIVES

The authors aimed to compare AEF rates before and after the adoption of active esophageal cooling.

METHODS

This institutional review board (IRB)-approved study was a prospective analysis of retrospective data, designed before collecting and analyzing the real-world data. The number of AEFs occurring in equivalent time frames before and after adoption of cooling using a dedicated esophageal cooling device (ensoETM, Attune Medical) were quantified across 25 prespecified hospital systems. AEF rates were then compared using generalized estimating equations robust to cluster correlation.

RESULTS

A total of 14,224 patients received active esophageal cooling during RF ablation across the 25 hospital systems, which included a total of 30 separate hospitals. In the time frames before adoption of active cooling, a total of 10,962 patients received primarily luminal esophageal temperature (LET) monitoring during their RF ablations. In the preadoption cohort, a total of 16 AEFs occurred, for an AEF rate of 0.146%, in line with other published estimates for procedures using LET monitoring. In the postadoption cohort, no AEFs were found in the prespecified sites, yielding an AEF rate of 0% (P < 0.0001).

CONCLUSIONS

Adoption of active esophageal cooling during RF ablation of the left atrium for the treatment of atrial fibrillation was associated with a significant reduction in AEF rate.

Pulsed Electric Fields in Oncology: A Snapshot of Current Clinical Practices and Research Directions from the 4th World Congress of Electroporation

The 4th World Congress of Electroporation (Copenhagen, 9-13 October 2022) provided a unique opportunity to convene leading experts in pulsed electric fields (PEF). PEF-based therapies harness electric fields to produce therapeutically useful effects on cancers and represent a valuable option for a variety of patients. As such, irreversible electroporation (IRE), gene electrotransfer (GET), electrochemotherapy (ECT), calcium electroporation (Ca-EP), and tumour-treating fields (TTF) are on the rise. Still, their full therapeutic potential remains underappreciated, and the field faces fragmentation, as shown by parallel maturation and differences in the stages of development and regulatory approval worldwide. This narrative review provides a glimpse of PEF-based techniques, including key mechanisms, clinical indications, and advances in therapy; finally, it offers insights into current research directions. By highlighting a common ground, the authors aim to break silos, strengthen cross-functional collaboration, and pave the way to novel possibilities for intervention. Intriguingly, beyond their peculiar mechanism of action, PEF-based therapies share technical interconnections and multifaceted biological effects (e.g., vascular, immunological) worth exploiting in combinatorial strategies.

Long-term follow-up experience with adjuvant therapy after irreversible electroporation of locally advanced pancreatic cancer

BACKGROUND

Irreversible electroporation (IRE) expands the surgical options for patients with unresectable pancreatic cancer. This study evaluated for differences in survival stratified by type of IRE and receipt of adjuvant chemotherapy.

METHODS

Patients with locally advanced pancreatic cancer treated by IRE (2012-2020) were retrospectively included. Overall survival (OS) and recurrence-free survival (RFS) were compared by type of IRE (in situ for local tumor control or IRE of potentially positive margins with resection) and by receipt of adjuvant chemotherapy.

RESULTS

Thirty-nine patients had IRE in situ, 61 had IRE for margin extension, and 19 received adjuvant chemotherapy. Most (97.00%) underwent induction chemotherapy. OS was 28.71 months (interquartile range [IQR] 19.17, 51.19) from diagnosis, with no difference by IRE type (hazard ratio [HR] 1.05 for margin extension [p = 0.85]) or adjuvant chemotherapy (HR 1.14 [p = 0.639]). RFS was 8.51 months (IQR 4.95, 20.17) with no difference by IRE type (HR 0.90 for margin extension [p = 0.694]) or adjuvant chemotherapy (HR 0.90 [p = 0.711]).

CONCLUSION

These findings suggest that adjuvant therapy may have limited benefit for patients treated with induction chemotherapy followed by local control with IRE for unresectable pancreatic cancer. Further study of the duration and timing of systemic therapy is warranted to maximize benefit and limit toxicity.

Safety and feasibility of irreversible electroporation for the pancreatic head in a porcine model

BACKGROUND

Irreversible electroporation (IRE) is a local non-thermal ablative technique which has been suggested as a potential cancer therapy. However, the specific anatomic characteristics of the pancreatic head make it challenging to perform any local ablation in this region. Therefore, the safety and feasibility of IRE in the pancreatic head region should be further explored.

AIM

To evaluate the safety of IRE in pancreatic head region including its effects on pancreatic ducts, vessels, and adjacent gastrointestinal organs.

METHODS

Eight landrace miniature pigs underwent IRE of pancreatic head tissue successfully, with a total of 16 lesions created. Laboratory testing including white blood cell (WBC) count and serum amylase before IRE with follow-up laboratory analysis and pathological examination at 1, 7, 14, and 28 d postablation were performed.

RESULTS

All pigs tolerated the ablation procedure without serious perioperative complications. Transiently elevated WBC count and amylase were observed at 24 h post-IRE, suggesting an acute pancreatic tissue damage which was confirmed by pathological observations. Vascular endothelial cells and pancreatic duct epithelial cells in ablation zone were also positive in terminal deoxynucleotidyl transferase dUTP nick end labeling staining. There was extensive duodenum mucosa damage with local hemorrhage 24 h after ablation, while regeneration of new villous structures were observed at 7 and 28 d post-IRE. Masson’s trichromatic staining showed that the extracellular matrix was still intact in vessels and pancreatic ducts, and even in the duodenum.

CONCLUSION

IRE ablation to the pancreatic head may be safe and feasible without long-term damage to the surrounding vital structures. However, risks of stress injuries in acute phase should be taken into consideration to prevent severe perioperative complications.

Simultaneous Gemcitabine and Percutaneous CT-Guided Irreversible Electroporation for Locally Advanced Pancreatic Cancer

Background

Irreversible electroporation (IRE) is a new local ablation technique for pancreatic cancer. The aim of this study is to analyse the safety and effectiveness of simultaneous gemcitabine and percutaneous CT-guided IRE for locally advanced pancreatic cancer (LAPC).

Materials and Methods

From October 2016 to January 2018, 61 patients with LAPC who received simultaneous gemcitabine and IRE therapy (GEM-IRE group, n = 31) or IRE alone therapy (IRE group, n = 30). Routine intravenous gemcitabine chemotherapy was performed 2 weeks after IRE in both groups.

Results

Technical success rates were 90.0% (27/30) and 93.3% (28/30) in the GEM-IRE and IRE groups. Compared with the IRE group, the GEM-IRE group exhibited longer overall survival (OS), local tumor progression free survival (LTPFS), and distant disease free survival (DDFS) from IRE (OS, 17.1 vs. 14.2 months, p=0.031; LTPFS, 14.6 vs. 10.2 months, p=0.045; DDFS, 15.4 vs. 11.7 months, p=0.071). Multivariate Cox regression analysis results suggested that tumor volume ≤37 cm³ and simultaneous gemcitabine with IRE were significant independent prognostic factors of OS, LTPFS, and DDFS. Four major adverse reactions occurred; all of them were resolved after symptomatic treatment.

Conclusions

Simultaneous gemcitabine and percutaneous CT-guided IRE therapy model was effective and well-tolerated therapeutic strategy in LAPC patients.

Irreversible Electroporation: An Emerging Immunomodulatory Therapy on Solid Tumors

Irreversible electroporation (IRE), a novel non-thermal ablation technique, is utilized to ablate unresectable solid tumors and demonstrates favorable safety and efficacy in the clinic. IRE applies electric pulses to alter the cell transmembrane voltage and causes nanometer-sized membrane defects or pores in the cells, which leads to loss of cell homeostasis and ultimately results in cell death. The major drawbacks of IRE are incomplete ablation and susceptibility to recurrence, which limit its clinical application. Recent studies have shown that IRE promotes the massive release of intracellular concealed tumor antigens that become an “in-situ tumor vaccine,” inducing a potential antitumor immune response to kill residual tumor cells after ablation and inhibiting local recurrence and distant metastasis. Therefore, IRE can be regarded as a potential immunomodulatory therapy, and combined with immunotherapy, it can exhibit synergistic treatment effects on malignant tumors, which provides broad application prospects for tumor treatment. This work reviewed the current status of the clinical efficacy of IRE in tumor treatment, summarized the characteristics of local and systemic immune responses induced by IRE in tumor-bearing organisms, and analyzed the specific mechanisms of the IRE-induced immune response. Moreover, we reviewed the current research progress of IRE combined with immunotherapy in the treatment of solid tumors. Based on the findings, we present deficiencies of current preclinical studies of animal models and analyze possible reasons and solutions. We also propose possible demands for clinical research. This review aimed to provide theoretical and practical guidance for the combination of IRE with immunotherapy in the treatment of malignant tumors.

Open irreversible electroporation for isolated local recurrence of pancreatic ductal adenocarcinoma after primary surgery

BACKGROUND/OBJECTIVES

Irreversible electroporation (IRE) is an emerging treatment for locally advanced pancreatic cancer (LAPC) which in some cohorts has been associated with severe complications. Additionally, re-resection of isolated local recurrence (ILR) after pancreatic ductal adenocarcinoma (PDAC) can improve survival. We investigated safety, feasibility and oncologic outcomes in the first report on open IRE for unresectable ILR of PDAC in a staged surgical approach.

METHODS

Records of the prospectively documented institutional database were screened for patients undergoing laparotomy in IRE-standby due to questionable resectability. Endpoints were morbidity, mortality and overall (OS) and progression free survival (PFS). Data of LAPC and ILR were compared statistically for safety and feasibility analysis.

RESULTS

Intraoperative IRE was performed in 11 ILR and 14 LAPC. Six (54.5%) ILR and 10 (71.4%) LAPC patients had postoperative complications, type and frequency did not differ significantly. Major complications occurred in one ILR and two LAPC patients. Median OS was 20.0 months (95% CI: 2.7-37.3) after IRE for ILR and 28 (17.4-38.6) for LAPC. Median PFS after IRE was seven months for both ILR (4.1-9.9; n = 9) and LAPC (2.3-11.7; n = 13).

CONCLUSION

Open IRE for unresectable ILR was associated with acceptable perioperative risk. In this small, highly selected subset of patients with limited therapeutic options ancillary treatment with IRE might improve survival. Randomized treatment studies are required to establish the definitive role of IRE as compared to palliative standards of care in unresectable recurrence of PDAC and inconvertible LAPC.

Safety of Irreversible Electroporation Ablation of the Pancreas

OBJECTIVES

To evaluate the safety of irreversible electroporation (IRE) on swine pancreatic tissue including its effects on peripancreatic vessels, bile ducts, and bowel.

METHODS

Eighteen Yorkshire pigs underwent IRE ablation of the pancreas successfully and without clinical complications. Contrast-enhanced computed tomography angiography and laboratory studies before the IRE ablation with follow-up computed tomography angiography, laboratory testing, and pathological examination up to 4 weeks postablation were performed.

RESULTS

In a subset of cases, anatomic peripancreatic vessel narrowing was seen by 1 week postablation, persisting at 4 weeks postablation, without apparent functional impairment of blood flow. Laboratory studies revealed elevated amylase and lipase at 24 hours post-IRE, suggestive of acute pancreatitis, which normalized by 4 weeks post-IRE. There was extensive pancreatic tissue damage 24 hours after IRE with infiltration of immune cells, which was gradually replaced by fibrotic tissue. Ductal regeneration without loss of pancreatic acinar tissue and glandular function was observed at 1 and 4 weeks postablation.

CONCLUSIONS

In our study, we demonstrated and confirmed the safety and minimal complications of IRE ablation in the pancreas and its surrounding vital structures. These results show the potential of IRE as an alternative treatment modality in patients with pancreatic cancer, especially those with locally advanced disease.

Minimally invasive image-guided therapy of primary and metastatic pancreatic cancer

Pancreatic cancer is a challenging malignancy with limited treatment options and poor life expectancy. The only curative option is surgical resection, but only 15%-20% of patients are resectable at presentation because more than 50% of patients has distant metastasis at diagnosis and the rest of them has locally advanced pancreatic cancer (LAPC). The standard of care first line treatment for LAPC patients is chemotherapy with or without radiation therapy. Recent developments in minimally invasive ablative techniques may add to the treatment armamentarium of LAPC. There are increasing number of studies evaluating these novel ablative techniques, including radiofrequency ablation, microwave ablation, cryoablation and irreversible electroporation. Most studies which included pancreatic tumor ablation, demonstrated improved overall survival in LAPC patients. However, the exact protocols are yet to set up to which stage of the treatment algorithm ablative techniques can be added and in what kind of treatment combinations. Patients with metastatic pancreatic cancer has dismal prognosis with 5-year survival is only 3%. The most common metastatic site is the liver as 90% of pancreatic cancer patients develop liver metastasis. Chemotherapy is the primary treatment option for patients with metastatic pancreatic cancer. However, when the tumor is not responding to chemotherapy or severe drug toxicity develops, locoregional liver-directed therapies can provide an opportunity to control intrahepatic disease progression and improve survival in selected patients. During the last decade new therapeutic options arose with the advancement of minimally invasive technologies to treat pancreatic cancer patients. These new therapies have been a topic of increasing interest due to the severe prognostic implications of locally advanced and metastatic pancreatic cancer and the low comorbid risk of these procedures. This review summarizes new ablative options for patients with LAPC and percutaneous liver-directed therapies for patients with liver-dominant metastatic disease.

Local ablation of pancreatic tumors: State of the art and future perspectives

BACKGROUND

Currently, the technologies most commonly used to treat locally advanced pancreatic cancer are radiofrequency ablation (RFA), microwave ablation, and irreversible (IRE) or reversible electroporation combined with low doses of chemotherapeutic drugs.

AIM

To report an overview and updates on ablative techniques in pancreatic cancer.

METHODS

Several electronic databases were searched. The search covered the years from January 2000 to January 2021. Moreover, the reference lists of the found papers were analysed for papers not indexed in the electronic databases. All titles and abstracts were analysed.

RESULTS

We found 30 studies (14 studies for RFA, 3 for microwave therapy, 10 for IRE, and 3 for electrochemotherapy), comprising 1047 patients, which were analysed further. Two randomized trials were found for IRE. Percutaneous and laparotomy approaches were performed. In the assessed patients, the median maximal diameter of the lesions was in the range of 2.8 to 4.5 cm. All series included patients unfit for surgical treatment, but Martin et al assessed a subgroup of patients with borderline resectable tumours who underwent resection with margin attenuation with IRE. Most studies administered chemotherapy prior to ablative therapies. However, several studies suggest that the key determinant of improved survival is attributable to ablative treatment alone. Nevertheless, the authors suggested chemotherapy before local therapies for several reasons. This strategy may not only downstage a subgroup of patients to curative-intent surgery but also support to recognize patients with biologically unfavourable tumours who would likely not benefit from ablation treatments. Ablation therapies seem safe based on the 1047 patients assessed in this review. The mortality rate ranged from 1.8% to 2%. However, despite the low mortality, the reported rates of severe post procedural complications ranged from 0%-42%. Most reported complications have been self-limiting and manageable. Median overall survival varied between 6.0 and 33 mo. Regarding the technical success rate, assessed papers reported an estimated rate in the range of 85% to 100%. However, the authors reported early recurrence after treatment. A distinct consideration should be made on whether local treatments induce an immune response in the ablated area. Preclinical and clinical studies have shown that RFA is a promising mechanism for inducing antigen-presenting cell infiltration and enhancing the systemic antitumour T-cell immune response and tumour regression.

CONCLUSION

In the management of patients with pancreatic cancer, the possibility of a multimodal approach should be considered, and conceptually, the combination of RFA with immunotherapy represents a novel angle of attack against this tumour.

Margin ACcentuation for resectable Pancreatic cancer using Irreversible Electroporation - Results from the MACPIE-I study

INTRODUCTION

Margin accentuation (MA) using Irreversible electroporation (IRE) offers an unique opportunity to reduce the R1 resections in resectable pancreatic cancer (RPC). This study aims to assess the rate of margin positivity using IRE for MA during pancreaticoduodenectomy (PD) for resectable pancreatic head tumours.

MATERIALS AND METHODS

Following ethical approval, MA using IRE was carried out in 20 consecutive patients to posterior and superior mesenteric vein (SMV) margin, and the pancreatic neck, prior to the PD resection. The control group (non-IRE; n = 91) underwent PD without MA over the study period, March 2018 to March 2020.

RESULTS

There was no difference between the two groups in terms of patients' age, gender, pre-op biliary drainage, site of malignancy or pre-operative TNM stage. The overall margin positive rate for IRE group was lesser (35.0%) when compared to non-IRE group (51.6%; p = 0.177), with significantly less posterior pancreatic margin positivity (5.0% vs. 25.3%; p = 0.046). When only treated margins (SMA margin excluded) were compared, the IRE group had significantly lower margin positive rates (20.0% vs. 51.6%; p = 0.013). There was no difference between the two groups in terms of intra- or post-operative complications. With a median follow-up of 15.6 months, the median DFS and OS for IRE and non-IRE groups were 17 and 18 months (p = 0.306) and 19 and 22 months (p = 0.227) respectively.

CONCLUSION

Our pilot study confirms the safety of MA using IRE for RPC, with reduction in margin positivity. These results as a proof of concept are promising and need further validation with a randomised controlled trial.

Locally Advanced Pancreatic Cancer: Percutaneous Management Using Ablation, Brachytherapy, Intra-arterial Chemotherapy, and Intra-tumoral Immunotherapy

PURPOSE OF REVIEW

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive neoplasms, bearing a terrible prognosis. Stage III tumors, also known as locally advanced pancreatic cancer (LAPC), are unresectable, and current palliative chemotherapy regimens have only modestly improved survival in these patients. At this stage of disease, interventional techniques may be of value and further prolong life. The aim of this review was to explore current literature on locoregional percutaneous management for LAPC.

RECENT FINDINGS

Locoregional percutaneous interventional techniques such as ablation, brachytherapy, and intra-arterial chemotherapy possess cytoreductive abilities and have the potential to increase survival. In addition, recent research demonstrates the immunomodulatory capacities of these treatments. This immune response may be leveraged by combining the interventional techniques with intra-tumoral immunotherapy, possibly creating a durable anti-tumor effect. This multimodality treatment approach is currently being examined in several ongoing clinical trials. The use of certain interventional techniques appears to improve survival in LAPC patients and may work synergistically when combined with immunotherapy. However, definitive conclusions can only be made when large prospective (randomized controlled) trials confirm these results.

Irreversible Electroporation (IRE) in Locally Advanced Pancreatic Cancer: A Review of Current Clinical Outcomes, Mechanism of Action and Opportunities for Synergistic Therapy

Locally advanced pancreatic cancer (LAPC) accounts for 30% of patients with pancreatic cancer. Irreversible electroporation (IRE) is a novel cancer treatment that may improve survival and quality of life in LAPC. This narrative review will provide a perspective on the clinical experience of pancreas IRE therapy, explore the evidence for the mode of action, assess treatment complications, and propose strategies for augmenting IRE response. A systematic search was performed using PubMed regarding the clinical use and safety profile of IRE on pancreatic cancer, post-IRE sequential histological changes, associated immune response, and synergistic therapies. Animal data demonstrate that IRE induces both apoptosis and necrosis followed by fibrosis. Major complications may result from IRE; procedure related mortality is up to 2%, with an average morbidity as high as 36%. Nevertheless, prospective and retrospective studies suggest that IRE treatment may increase median overall survival of LAPC to as much as 30 months and provide preliminary data justifying the well-designed trials currently underway, comparing IRE to the standard of care treatment. The mechanism of action of IRE remains unknown, and there is a lack of data on treatment variables and efficiency in humans. There is emerging data suggesting that IRE can be augmented with synergistic therapies such as immunotherapy.

Irreversible Electroporation in Locally Advanced Pancreatic Adenocarcinoma: Aiming to Improve Overall Survival

Irreversible electroporation (IRE) is a non-thermic ablation therapy which has been proposed for locally advanced pancreatic adenocarcinoma (LAPC) as well as for the local control of other types of tumors (kidney or liver). Its use has been extended in the last few years worldwide. Its advantage over other ablation techniques is that it only affects the lipids bilayer of the cell membrane avoiding vascular damage. Safety and viability have been demonstrated in recent studies. Overall survival seems (OS) to improve when it is combined with chemotherapy compared to chemotherapy with or without radiotherapy. Clinical trials should confirm these encouraging data.

Initial experience of irreversible electroporation for locally advanced pancreatic cancer in a Korean population

BACKGROUND

Locally advanced pancreatic cancer (LAPC) is one of the most aggressive malignancies. Irreversible electroporation (IRE) is a novel technique that uses a non-thermal ablation to avoid vessel or duct injury.

PURPOSE

To investigate the safety and efficacy of IRE for the management of LAPC in a Korean population.

MATERIAL AND METHODS

Twelve patients (median age 64 years; age range 46-73 years) treated between December 2015 and March 2017 underwent intraoperative IRE for LAPC. Technical success and clinical outcomes, including complications, serum pancreatic enzyme levels, overall survival (OS), and progression-free survival (PFS), were evaluated.

RESULTS

Tumors were located in the pancreas head in 7 (58.3%) patients and in the body/tail in 5 (41.7%) patients. The median tumor diameter in the longest axis was 3.1 cm. Vascular invasion was observed in all patients and bowel abutment in 3 (25%) patients. Technical success was achieved in all patients. The median serum levels of amylase and lipase were 55 U/L and 31 U/L, respectively, at baseline, increased to 141.5 U/L (P = 0.008) and 53 U/L (P = 0.505), respectively, one day after IRE, and normalized after one week. The rate of 30-day mortality of unknown relation was 8.3% (one individual experienced massive hematemesis 12 days after IRE). The median OS from diagnosis and IRE was 24.5 months and 13.5 months, respectively. The median PFS from diagnosis and IRE was 19.2 months and 8.6 months, respectively.

CONCLUSION

For patients with LAPC, IRE appears to be a promising treatment modality with an acceptable safety profile.

Assessment of Ablation Therapy in Pancreatic Cancer: The Radiologist's Challenge

This article provides an overview of imaging assessment of ablated pancreatic cancer. Only studies reporting radiological assessment on pancreatic ablated cancer were retained. We found 16 clinical studies that satisfied the inclusion criteria. Radiofrequency ablation and irreversible electroporation have become established treatment modalities because of their efficacy, low complication rates, and availability. Microwave Ablation (MWA) has several advantages over radiofrequency ablation (RFA), which may make it more attractive to treat pancreatic cancer. Electrochemotherapy (ECT) is a very interesting emerging technique, characterized by low complication rate and safety profile. According to the literature, the assessment of the effectiveness of ablative therapies is difficult by means of the Response Evaluation Criteria in Solid Tumors (RECIST) criteria that are not suitable to evaluate the treatment response considering that are related to technique used, the timing of reassessment, and the imaging procedure being used to evaluate the efficacy. RFA causes various appearances on imaging in the ablated zone, correlating to the different effects, such as interstitial edema, hemorrhage, carbonization, necrosis, and fibrosis. Irreversible electroporation (IRE) causes the creation of pores within the cell membrane causing cell death. Experimental studies showed that Diffusion Weigthed Imaging (DWI) extracted parameters could be used to detect therapy effects. No data about functional assessment post MWA is available in literature. Morphologic data extracted by Computed Tomography (CT) or Magnetic Resonance Imaging (MRI) do not allow to differentiate partial, complete, or incomplete response after ECT conversely to functional parameters, obtained with Position Emission Tomography (PET), MRI, and CT.

Imaging response evaluation after local ablative treatments in locally advanced pancreatic cancer: an expedited systematic review

BACKGROUND

Several local ablative modalities have been introduced for the treatment of locally advanced pancreatic cancer (LAPC). However, there is no consensus on how to evaluate the imaging response after treatment. A systematic review was performed regarding the use of imaging for response assessment in LAPC.

METHODS

A systematic literature search was conducted in PubMed. Studies reporting imaging outcomes were included in the review. Studies were excluded if the imaging outcomes could not be differentiated between different disease stages, tumor histology or surgical approaches.

RESULTS

Thirty-four studies were included in the analysis. Fourteen studies used standardized response criteria, while six studies did not report the response evaluation method. The rest used self-determined criteria, absolute size comparisons or similar methods. One study found a correlation between early systemic progression (<6 months) and overall survival.

CONCLUSION

There was notable variation in the use of imaging for response assessment in LAPC. This significantly hinders cross-comparison of results among studies. There is currently only sparse evidence of an association between imaging responses and overall survival. The field calls for standardized recommendations regarding the choice of response assessment method, timing of scans, target definition and reporting of outcomes.

Preliminary clinical application of the robot-assisted CT-guided irreversible electroporation ablation for the treatment of pancreatic head carcinoma

BACKGROUND

To evaluate the feasibility and safety of a robot-guided irreversible electroporation (IRE) ablation system for the treatment of pancreatic head carcinoma.

METHODS

A total of 20 cases with pancreatic head carcinoma were divided into two groups: 11 cases in group A with manual probe placement and 9 cases in group B with robotic navigated probe placement. The two groups were compared in terms of planning time before puncture, puncture time, the total time of electrode deployment, number of scans, and punctual accuracy of the single electrode.

RESULTS

Each probe was successfully punctured, and no complications were detected. P-values were calculated for all the parameters, using the SPSS 25.0 software and the t test.

CONCLUSIONS

The new robot can reduce the total operating time as compared to the manual probe placement with the same accuracy in the IRE of pancreatic head carcinoma.

Effects of high-intensity focused ultrasound treatment on peripancreatic arterial and venous blood vessels in pancreatic cancer

The present study aimed to evaluate the safety of high-intensity focused ultrasound (HIFU) treatment on peripancreatic arterial and venous blood vessels in patients with pancreatic cancer. This trial included 15 patients with pancreatic cancer (9 females and 6 males; age, 39-81 years; median age, 62 years). All patients underwent preoperative computed tomography (CT) or magnetic resonance imaging (MRI) and color Doppler flow imaging (CDFI) to assess the vascular hemodynamics of peripancreatic arterial and venous blood vessels pre-treatment. These patients were re-examined within 1 week post-HIFU treatment. Then, vascular adverse events were observed and followed up clinically. Prior to HIFU treatment, vessel involvement was recorded in 13 patients, including tumor lesions invading 19 veins and 14 arteries, which refers to the growth of pancreatic tumor lesions surrounding blood vessels, or tumor growth into blood vessels. In addition, 9 veins and 13 arteries were <1 cm from the lesions. The hemodynamic parameters of peripancreatic vessels were measured using CDFI, including mean blood flow velocity, peak systolic blood flow velocity, vascular resistance index, vascular pulsatility index, vascular diameter, vascular blood flow and other indicators, to assess vascular perfusion in CT/MRI. There were no significant differences in preoperative and postoperative hemodynamic data (P>0.05). Overall, HIFU demonstrated no negative effects on peripancreatic arterial and venous blood vessels in patients with pancreatic cancer, even with tumor lesions wrapped in blood vessels. In addition, no complications of vascular stenosis and vascular adverse events were observed in the present study.

The efficacy and safety of the open approach irreversible electroporation in the treatment of pancreatic cancer: A systematic review

BACKGROUND

Irreversible Electroporation (IRE) is a novel non-thermal ablation technique used in patients with locally advanced pancreatic cancer (LAPC), in the proximity of sensitive structures such as vessels, intestinal wall and the bile duct. Currently, it is only used in the setting of clinical trials. This systematic review aimed to tackle the knowledge gap in the literature, in relation to the safety and efficacy of the open approach IRE.

METHODS

MEDLINE, EMBASE and Cochrane libraries were searched for English language articles published from January 2000 to December 2019. Data related to safety and efficacy were extracted.

RESULTS

Nine studies involving 460 patients with LAPC were included. Open approach IRE was associated with high morbidity (29.4%) but with a survival benefit compared to traditional treatment. Median overall survival (OS) was at 17.15 months. Major morbidity was at 10.2% and mortality at 3.4%.

CONCLUSIONS

Despite the paucity of literature and the low quality of evidence, the results regarding safety and efficacy appear to be encouraging. The high morbidity seems to be mitigated by a demonstrated improvement in OS. The potential of this technique is more evident when mortality and major morbidity are considered, since they are at acceptable levels. The limitations of this review have made it difficult to extract definitive conclusions. Higher quality evidence is needed in the form of large-scale multicentre randomized controlled trials. It remains to be elucidated whether the rate of adverse events decreases as our experience with this technique increases.

High-Voltage Electrical Pulses in Oncology: Irreversible Electroporation, Electrochemotherapy, Gene Electrotransfer, Electrofusion, and Electroimmunotherapy

This review summarizes the use of high-voltage electrical pulses (HVEPs) in clinical oncology to treat solid tumors with irreversible electroporation (IRE) and electrochemotherapy (ECT). HVEPs increase the membrane permeability of cells, a phenomenon known as electroporation. Unlike alternative ablative therapies, electroporation does not affect the structural integrity of surrounding tissue, thereby enabling tumors in the vicinity of vital structures to be treated. IRE uses HVEPs to cause cell death by inducing membrane disruption, and it is primarily used as a radical ablative therapy in the treatment of soft-tissue tumors in the liver, kidney, prostate, and pancreas. ECT uses HVEPs to transiently increase membrane permeability, enhancing cellular cytotoxic drug uptake in tumors. IRE and ECT show immunogenic effects that could be augmented when combined with immunomodulatory drugs, a combination therapy the authors term electroimmunotherapy. Additional electroporation-based technologies that may reach clinical importance, such as gene electrotransfer, electrofusion, and electroimmunotherapy, are concisely reviewed. HVEPs represent a substantial advancement in cancer research, and continued improvement and implementation of these presented technologies will require close collaboration between engineers, interventional radiologists, medical oncologists, and immuno-oncologists.

Prevention of Procedural Hypertension in the Irreversible Electroporation Ablation of Liver and Pancreatic Tumors Based on Distance from the Adrenal Gland

Background and objective

When irreversible electroporation (IRE) ablation of abdominal tumors, procedural hypertension often occurs, which often affects the progress of the ablation. Until now, there is no reasonable explanation for this phenomenon. The objective of this research was to explore the cause and solution of procedural hypertension in percutaneous IRE.

Methods

In this study, the treatment data of 4 consecutive groups of patients were used to confirm the cause of intraoperative hypertension and then verify the solution. A total of 155 patients with procedural hypertension were screened based on their medical records of pancreatic or hepatic IRE treatment. Procedural hypertension was monitored in 21 new patients, the correlation between serum catecholamines and hypertension was recorded and evaluated using regression analysis. Forty new patients were divided into two groups (distance from needle tip to adrenal gland, < 2 cm vs ≥ 2 cm), and the blood pressure was recorded and compared with two-way ANOVA. Eleven patients with ablative distance <2 cm were treated in advance with phentolamine to observe for the occurrence of procedural hypertension.

Results

Of the 21 re-enrolled patients with ablation of the pancreas and liver tumors, 9 developed intraoperative hypertension with significantly elevated serum catecholamines levels, epinephrine, norepinephrine and dopamine are all positively associated with hypertension, with P values were 0.0003, 0.0253, and 0.0015, respectively. For the two groups with different needle-insertion distances, hypertension in the < 2 cm group was more significant than that in the other group (for procedural hypertension, P< 0.01; for heart rate, P< 0.05), which was considered as a high-risk group. The occurrence of intraoperative hypertension could be completely prevented by using phentolamine prior to treatment.

Conclusion

Hypertension occurs frequently during hepatic and pancreatic IRE because of the damage of adrenal gland. The safe distance of ablation probe for the adrenal gland was 2 cm. For high-risk patients, early drug prevention works well.

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.

Prognostic factor analysis of irreversible electroporation for locally advanced pancreatic cancer - A multi-institutional clinical study in Asia

INTRODUCTION

Irreversible electroporation (IRE) is a modality that utilizes high electric voltage to cause cell apoptosis. IRE has been used to treat locally advanced pancreatic cancer (LAPC). However, studies of IRE via surgical approaches for LAPC are limited. This study aims to analyse the outcomes and related prognostic factors of IRE for Asian patients with LAPC.

MATERIALS AND METHODS

From 2012 to 2017, this prospective trial for using IRE through surgical approaches for LAPC was conducted in 11 medical centres in Asia. All related and treatment outcomes were analysed from a prospective database.

RESULTS

Seventy-four patients were enrolled. Thirty complications occurred in thirteen (17.6%) patients without mortality. The electrode placement direction (anteroposterior vs. craniocaudal, HR = 14.2, p < 0.01) and gastrointestinal invasion (HR = 15.7, p < 0.01) were significant factors for complications. The progression-free survival (PFS) rate in one year, three years, and five years were 69.1%, 48.7%, and 28.8%, and the overall survival (OS) rate in one year, three years, and five years were 97.2%, 53%, and 31.2%. In univariate analysis, the chemotherapy regimen, local tumour recurrence, axial tumour length, tumour volume, and serum carbohydrate antigen 19-9 levels were all significantly associated with PFS and OS. In multivariate analysis, the chemotherapy regimen was the only significant factor associated with PFS and OS. TS-1 (Tegafur, gimeracil, and oteracil) group has superior survival outcome than gemcitabine group.

CONCLUSION

This study showed that combined induction chemotherapy and surgical IRE for LAPC is safe. For well-selected patients, IRE can achieve encouraging survival outcomes.

Intraoperative Irreversible Electroporation in Locally Advanced Pancreatic Cancer: A Guide for the Interventional Radiologist

Efforts to improve mortality associated with locally advanced pancreatic cancer (LAPC) have shown minimal gains despite advances in surgical technique, systemic treatments, and radiation therapy. Locoregional therapy with ablation has not been routinely adopted due to the high risk of complications associated with thermal destruction of the pancreas. Irreversible electroporation (IRE) is an emerging, nonthermal, ablative technology that has demonstrated the ability to generate controlled ablation of LAPC while preserving pancreatic parenchymal integrity. IRE may be performed percutaneously or via laparotomy and will commonly involve multidisciplinary treatment teams. This article will describe the technical aspects of how multidisciplinary IRE is performed during laparotomy at a single tertiary care institution.

Systematic Review of Irreversible Electroporation Role in Management of Locally Advanced Pancreatic Cancer

Background: Ablative techniques provide in patients with locally advanced pancreatic cancer (LAPC) symptomatic relief, survival benefit and potential downsizing. Irreversible Electroporation (IRE) represents potentially an ideal solution as no thermal tissue damage occurs. The purpose of this review is to present an overview on safety, feasibility, oncological results, survival and quality of life improvement obtained by IRE. Methods: A systematic search was performed in PubMed, regarding the use of IRE on PC in humans for studies published in English up to March 2019. Results: 15 original studies embodying 691 patients with unresectable LAPC who underwent IRE were included. As emerged, IRE works better on tumour sizes between 3–4 cm. Oncological results are promising: median OS from diagnosis or treatment up to 27 months. Two groups investigated borderline resectable tumours treated with IRE before resection with margin attenuation, whereas IRE has proved to be effective in pain control. Conclusions: Electroporation is bringing new hopes in LAPC management. The first aim of IRE is to offer a palliative treatment. Further efforts are needed for patient selection, as well as the use of IRE for ‘margin accentuation’ during surgical resection. Even if promising, IRE needs to be validated in large, randomized, prospective series.

Is irreversible electroporation safe and effective in the treatment of hepatobiliary and pancreatic cancers?

BACKGROUND

Irreversible electroporation (IRE) is a novel ablative technique for hepatobiliary and pancreatic cancers. This review summarizes the data regarding the safety and efficacy of IRE in the treatment of hepatobiliary and pancreatic cancers.

DATA SOURCES

Studies were identified by searching PubMed and Embase for articles published in English from database inception through July 31, 2017. For inclusion, each clinical study had to report morbidity and survival data on hepatobiliary and pancreatic cancers treated with IRE and contain at least 10 patients. Studies that met these criteria were included for analysis. Two authors assessed each clinical study for data extraction. The controversial parts were resolved through discussion with seniors.

RESULTS

A total of 24 clinical studies were included. Fourteen focused on hepatic ablation with IRE comprising 437 patients with 666 lesions of different tumor types. Two patients (0.5%) died after the IRE procedure. Morbidity of hepatic ablation with IRE ranged from 7% to 35%. Most complications were mild. Complete response for hepatic tumors was reported as 57%-97%. Ten studies with 455 patients focused on pancreatic IRE. The overall mortality of IRE in pancreatic cancer was 2%. Overall severe morbidity of IRE in pancreatic cancer ranged from 0 to 20%. The median overall survival after IRE ranged from 7 to 23 months. Patients treated with IRE combined with surgical resection showed a longer overall survival.

CONCLUSIONS

IRE significantly improves the prognosis of advanced hepatobiliary and pancreatic malignances, and companied with less complications. Hence, IRE is a relatively safe and effective non-thermal ablation strategy and potentially recommended as an option for therapy of patients with hepatobiliary and pancreatic malignances.

Systematic Review of Surgical and Percutaneous Irreversible Electroporation in the Treatment of Locally Advanced Pancreatic Cancer

OBJECTIVE

The aim of the present systematic review was to collect, analyze, and critically evaluate the role of irreversible electroporation (IRE) in locally advanced pancreatic cancer (LAPC). Furthermore, we sought to analyze the different approaches of IRE (open, laparoscopic, and percutaneous) and assess the relative outcomes.

METHODS

A systematic review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Using the MEDLINE (1966-2018), Scopus (2004-2018), Google Scholar (2004-2018) and ClinicalTrials.gov databases, eligible articles published up to August 2018 were included. The following keywords were applied: 'irreversible electroporation', 'IRE', 'LAPC', 'unresectable pancreatic cancer', 'palliative treatment', 'locally advanced pancreatic cancer', 'ablation' and 'ablative treatment'.

RESULTS

IRE for LAPC was feasible and safe; however, it was associated with morbidity in approximately one in three patients, some of whom experienced serious complications, particularly after surgical IRE. In addition, while mortality following IRE was uncommon, it did occur in 2% of patients. While some studies suggested a survival benefit, others failed to note an improvement in long-term outcomes following IRE compared with other therapies.

CONCLUSIONS

Providers and patients need to be aware of the potential morbidity and mortality associated with IRE. In addition, based on the literature to date, the survival benefit of IRE for LAPC remains to be elucidated. Conclusive and definitive evidence to support a survival benefit of IRE does not currently exist. Future multicenter, randomized, prospective trials are needed to clarify the role of IRE in patients with LAPC.

Palliative therapy in pancreatic cancer-interventional treatment with radiofrequency ablation/irreversible electroporation

Pancreatic cancer (PC) is a solid tumor with still a dismal prognosis. Diagnosis is usually late, when the disease is metastatic or locally advanced (LAPC). Only 20% of PC are amenable to surgery at the time of diagnosis and the vast majority of them, despite radically resected will unavoidably recur. The treatment of LAPC is a challenge. Current guidelines suggest to adopt systemic therapies upfront, based on multi-drugs chemotherapy regimens. However, the vast majority of patients will never experience conversion to surgical exploration and radical resection. Thus, there a large subgroup of LAPC patients where the only therapeutic chance is to offer palliative treatments, such as interventional ablative treatments, in order to obtain a cytoreduction of the tumor, trying to delay its growth and spread. Radiofrequency ablation (RFA) and irreversible electroporation (IRE) demonstrated to be safe and effective in obtaining a local control of the disease with some promising oncological results in terms of overall survival (OS). However, they should be adopted as a treatment strategy to adopt in parallel with other systemic therapies, within multidisciplinary choices. They are not free from complications, even serious, thus they should applied only in specialized centers of pancreatology. This review depicts the state of the art of the two techniques.

Irreversible Electroporation in pancreatic ductal adenocarcinoma: Is there a role in conjunction with conventional treatment?

BACKGROUND

The incidence of pancreatic ductal adenocarcinoma (PDAC) is rapidly increasing. Up to 30% of patients present with locally advanced disease and therefore are not candidates for surgery. Locally advanced pancreatic cancer (LAPC) is an emerging entity lacking in level III evidence-based recommendations for its treatment. Currently, systemic chemotherapy is the main treatment for LAPC. However, due to lack of response or disease progression, downsizing of the tumour, making it resectable is successful in only a small proportion of patients. Radiotherapy is often advocated to improve local disease control if there is stability following chemotherapy. Recently, Irreversible Electroporation (IRE), a novel non-thermal ablation technique, has been proposed for the treatment of LAPC.

AIMS AND METHODS

This narrative review aims to explore the potential role and timing for the use of IRE in patients with LAPC.

RESULTS

To date, there is limited and inconsistent level I and II evidence available in the literature regarding the use of IRE for the treatment of PDAC.

DISCUSSION

Although some of the preliminary experience of the use of IRE in patients with LAPC is encouraging, it should only be used after conventional evidence-based treatments and/or within the research context.

Irreversible Electroporation in Patients with Pancreatic Cancer: How Important Is the New Weapon?

Background

Pancreatic cancer (PC) is a deadly disease with poor prognosis in the general population. We aimed to quantitate overall survival of patients with PC after irreversible electroporation (IRE) and the incidence of relevant complications.

Methods

We performed a literature search via five electronic databases (PubMed, Embase, Web of Science, Scopus, and Cochrane Library databases) up to August 2017. The primary outcomes were overall survival and prognosis. Secondary outcomes included the response of post-IRE complications. Fixed-effects or random-effects meta-analysis was conducted to pool these data.

Results

A total of 15 eligible articles involving 535 patients were included. The primary outcomes showed that the pooled prevalence estimates of overall survival were 94.1% (95% CI: 90.7–97.5), 80.9% (95% CI: 72.5–89.4), 54.5% (95% CI: 38.3–70.6), and 33.8% (95% CI: 14.2–53.5) at 3, 6, 12, and 24 months, and the pooled prevalence data of complete response (CR) at 2 months, partial response (PR) at 3 months, and progression at 3 months were 12.5% (95% CI: 2.9–22.2), 48.5% (95% CI: 39.4–57.6), and 19.7% (95% CI: 7.3–32.2), respectively. The secondary outcomes showed that the pooled prevalence values of post-IRE complications were abscess 6.6% (95% CI: 0.2–13), fistula 10.6% (95% CI: 2.5–18.7), pain 33.5% (95% CI: 14.5–52.5), infection 16.1% (95% CI: 3.9–28.4), thrombosis 4.9% (95% CI: 1.2–8.5), pancreatitis 7.2% (95% CI: 3.1–11.2), bleeding 4.2% (95% CI: −0.5–8.9), cholangitis 4.2% (95% CI: −0.5–8.9), nausea 9.6% (95% CI: 4.4–14.8), biliary obstruction 13.8% (95% CI: 4.2–23.3), chest tightness 7.6% (95% CI: 0.5–14.6), and hypoglycemia 5.9% (95% CI: −0.4–12.2).

Conclusions

This meta-analysis indicated a clear survival benefit for PC patients who received irreversible electroporation therapy, although future safety and effectivity monitoring from more large-scale studies will be needed.

Locally Advanced Pancreatic Cancer: A Review of Local Ablative Therapies

Pancreatic cancer is typically characterized by its aggressive tumor growth and dismal prognosis. Approximately 30% of patients with pancreatic cancer present with locally advanced disease, broadly defined as having a tumor-to-artery interface >180°, having an unreconstructable portal vein or superior mesenteric vein and no signs of metastatic disease. These patients are currently designated to palliative systemic chemotherapy, though median overall survival remains poor (approximately 11 months). Therefore, several innovative local therapies have been investigated as new treatment options for locally advanced pancreatic cancer (LAPC). This article provides an overview of available data with regard to morbidity and oncological outcome of novel local therapies for LAPC.

The role of irreversible electroporation (IRE) for locally advanced pancreatic cancer: a systematic review of safety and efficacy

OBJECTIVES

Irreversible electroporation (IRE) is a new modality for tumor ablation. Electrodes are placed around the tumor, and a pulsed, direct current with a field strength of 2000 V/cm is delivered. The direct current drives cells into apoptosis and cell death without causing significant heating of the tissues, which spares the extracellular matrix and proteins. The purpose of this review was to evaluate current experience of IRE for the ablation of pancreatic cancer.

MATERIAL AND METHODS

We searched PubMed for all studies of IRE in human pancreatic cancer in English reporting at least 10 patients.

RESULTS

The search yielded 10 studies, comprising a total of 446 patients. Percutaneous IRE was done in 142 patients, while 304 patients were treated during laparotomy. Tumor sizes ranged from median 2.8 to 4.5 cm. Post-procedural complications occurred in 35% of patients, most of them were less severe. Nine patients (2.0%) died after the procedure. The technical success rate was 85-100%. The median recurrence-free survival was 2.7-12.4 months after IRE treatment. The median overall survival was 7-23 months postoperatively. The longest overall survival was noted when IRE was used in conjunction with pancreatic resection.

CONCLUSIONS

IRE seems feasible and safe with a low post-procedural mortality. Further efforts are needed to address patient selection and efficacy of IRE, as well as the use of IRE for 'margin accentuation' during surgical resection.

Postoperative inflammation as a possible cause of portal vein thrombosis after irreversible electroporation for locally advanced pancreatic cancer

Portal vein thrombosis (PVT) is a rare but serious postoperative complication associated with irreversible electroporation (IRE). We report a case of postoperative PVT in a 54-year-old woman who underwent IRE for locally advanced pancreatic cancer. Drain removal and discharge of the patient from the hospital were scheduled on postoperative day (POD) 7; however, a magnetic resonance imaging scan revealed the presence of PVT. We suspected postoperative inflammation in the pancreas as the main cause of PVT. However, the patient did not undergo any medical treatment because she did not have any clinical symptoms, and she was discharged on POD 8.

Expression and Prognostic Value of Indoleamine 2,3-dioxygenase in Pancreatic Cancer

Background:

Indoleamine 2,3-dioxygenase (IDO), an enzyme for tryptophan metabolism through the kynurenine pathway, exhibits an immunosuppressive effect and induces immune tolerance in tumor cells. The effects of IDO on pancreatic cancer are poorly understood. This study aimed to investigate the expression and prognostic significance of IDO in pancreatic cancer.

Methods:

We evaluated the protein expression of IDO in PANC-1, CFPAC-1, and BxPC-3 cell lines with or without 48 h treatment by 500 U/ml interferon-γ (IFN-γ). We performed immunohistochemical staining and Western blot analysis for IDO expression in both pancreatic cancer and normal pancreas tissues obtained from Chinese PLA General Hospital from July 2012 to December 2013. Survival analysis was performed to correlate IDO expression and histopathologic parameters with overall survival. The Kaplan-Meier method and Cox proportional hazards regression model were conducted.

Results:

PANC-1, CFPAC-1, and BxPC-3 cell lines expressed IDO at the protein level, and the relative expression amount increased after stimulation with 500 U/ml IFN-γ. Immunohistochemical analysis results revealed that high IDO expression was observed in 59% of pancreatic adenocarcinoma tissues. Compared with normal pancreatic tissues, pancreatic adenocarcinoma showed significantly higher IDO expression levels, especially among patients with high tumor node metastasis (TNM) stages (χ² = 4.550, P = 0.030), poor histological differentiation (χ² = 5.690, P = 0.017), and lymph node metastasis (χ² = 4.340 P = 0.037). Kaplan-Meier survival curves showed that high IDO expression was correlated with low survival rates (hazard ratio [HR] = 0.49 P = 0.009). Multivariate analysis using Cox proportional hazards model indicated that lymph node metastasis (HR = 0.35 P = 0.010) and IDO expression (HR = 0.42 P = 0.020) were two independent prognostic predictors of pancreatic adenocarcinoma.

Conclusions:

The study confirmed that high IDO expression in pancreatic adenocarcinoma was related to poor prognosis of patients. These findings provided evidence that IDO was involved in pancreatic adenocarcinoma progression and might serve as a relevant therapeutic target.