Efficacy of preoperative immunonutrition in locally advanced pancreatic cancer undergoing irreversible electroporation (IRE)

Monitoring the effect of perioperative nutritional care on body composition and functional status in patients with carcinoma of gastrointestinal and hepatobiliary system and pancreas

BACKGROUND

The significance of nutritional care in the management of cancer, particularly in the surgical treatment of abdominal cancer, is increasingly acknowledged. Body composition analysis, such as the Bioelectric impedance assay (BIA), and functional tests, e.g., handgrip strength, are used when assessing nutritional status alongside general and nutritional history, clinical examination, and laboratory tests. The primary approach in nutritional care is individually adjusted nutritional counselling and the use of medical nutrition, especially oral nutritional supplements. The aim of the study was to investigate the effects of perioperative nutritional care on body composition and functional status in patients with carcinoma of the gastrointestinal tract, hepatobiliary system, and pancreas.

PATIENTS AND METHODS

47 patients were included, 27 received preoperative and postoperative nutritional counselling and oral nutritional supplements (Group 1), while 20, due to surgical or organisational reasons, received nutritional care only postoperatively (Group 2). The effect of nutritional therapy was measured with bioimpedance body composition and handgrip measurements.

RESULTS

Group 2 had a higher average Nutritional Risk Screening (NRS) 2002 score upon enrolment (3 vs. 2 points); however, there was no difference when malnutrition was assessed using Global Leadership in Malnutrition (GLIM) criteria. There was a relative increase in lean body mass and fat-free mass index (FFMI) 7 days after surgery in group 1 (+4,2% vs. -2,1% in group 2). There was no difference in handgrip strength.

CONCLUSIONS

Our results indicate that combined preoperative and postoperative nutritional care is superior to only postoperative nutritional care. It seems to prevent statistically significant lean mass loss 7 days after surgery but not after 14 days or 4 weeks.

Nutrition as prevention for improved cancer health outcomes: a systematic literature review

BACKGROUND

Among adults with cancer, malnutrition is associated with decreased treatment completion, more treatment harms and use of health care, and worse short-term survival. To inform the National Institutes of Health Pathways to Prevention workshop, "Nutrition as Prevention for Improved Cancer Health Outcomes," this systematic review examined the evidence for the effectiveness of providing nutrition interventions before or during cancer therapy to improve outcomes of cancer treatment.

METHODS

We identified randomized controlled trials enrolling at least 50 participants published from 2000 through July 2022. We provide a detailed evidence map for included studies and grouped studies by broad intervention and cancer types. We conducted risk of bias (RoB) and qualitative descriptions of outcomes for intervention and cancer types with a larger volume of literature.

RESULTS

From 9798 unique references, 206 randomized controlled trials from 219 publications met the inclusion criteria. Studies primarily focused on nonvitamin or mineral dietary supplements, nutrition support, and route or timing of inpatient nutrition interventions for gastrointestinal or head and neck cancers. Most studies evaluated changes in body weight or composition, adverse events from cancer treatment, length of hospital stay, or quality of life. Few studies were conducted within the United States. Among intervention and cancer types with a high volume of literature (n = 114), 49% (n = 56) were assessed as high RoB. Higher-quality studies (low or medium RoB) reported mixed results on the effect of nutrition interventions across cancer and treatment-related outcomes.

CONCLUSIONS

Methodological limitations of nutrition intervention studies surrounding cancer treatment impair translation of findings into clinical practice or guidelines.

Patient Selection and Outcomes of Laparoscopic Microwave Ablation of Hepatocellular Carcinoma

Background: Laparoscopic microwave ablation (MWA) of hepatocellular carcinoma is underutilized and predictors of survival in this setting are not well characterized. Methods: The prognostic value of clinicopathologic variables was evaluated on progression-free survival (PFS) and overall survival (OS) by univariate and multivariate analyses. The aim of this study was to evaluate a preferred laparoscopic MWA approach in HCC patients that are not candidates for percutaneous ablation and further classify clinicopathologic factors that may predict survival outcomes following operative MWA in the setting of primary HCC. Results: 184 patients with HCC (median age 66, (33–86), 70% male) underwent laparoscopic MWA (N = 162, 88% laparoscopic) compared to 12% undergoing open MWA (N = 22). Median PFS was 29.3 months (0.2–170) and OS was 44.2 months (2.8–170). Ablation success was confirmed in 100% of patients. Ablation recurrence occurred in 3% (6/184), and local/hepatic recurrence occurred in 34%, at a median time of 19 months (9–18). Distant progression was noted in 8%. Median follow up was 34.1 months (6.4–170). Procedure-related complications were recorded in six (9%) patients with one 90-day mortality. Further, >1 lesion, AFP levels ≥ 80 ng/mL, and an “invader” on pre-operative radiology were associated with increased risk of progression (>1 lesion HR 2.92, 95% CI 1.06 –7.99, p = 0.04, AFP ≥ 80 ng/mL HR 4.16, 95% CI 1.71–10.15, p = 0.002, Invader HR 3.16, 95% CI 1.91–9.15, p = 0.002 ) and mortality (>1 lesion HR 3.62, 95% CI 1.21–10.81, p = 0.02], AFP ≥ 80 ng/mL HR 2.87, 95% CI 1.12–7.35, p = 0.01, Invader HR 3.32, 95% CI 1.21–9.81, p = 0.02). Conclusions: Preoperative lesion number, AFP ≥ 80 ng/mL, and an aggressive imaging characteristic (Invader) independently predict PFS and OS following laparoscopic operative MWA.

Postoperative Poor Oral Intake After Distal Pancreatectomy

OBJECTIVES

Poor oral intake (POI) without an identifiable cause is frequently observed after distal pancreatectomy (DP). This study was designed to investigate the incidence and risk factors of POI after DP, and its impact on the length of hospital stay.

METHODS

The prospectively collected data of patients who received DP were retrospectively reviewed. A diet protocol after DP was followed, and POI after DP was defined as the oral intake being less than 50% of the daily requirement and parenteral calorie supply being required on postoperative day 7.

RESULTS

Of the 157 patients, 21.7% (34) experienced POI after DP. The multivariate analysis revealed that the remnant pancreatic margin (head; hazard ratio, 7.837; 95% confidence interval, 2.111-29.087; P = 0.002) and postoperative hyperglycemia >200 mg/dL (hazard ratio, 5.643; 95% confidence interval, 1.482-21.494; P = 0.011) were independent risk factors for POI after DP. The length of hospital stay (median [range]) of the POI group was significantly longer than that of the normal diet group (17 [9-44] vs 10 [5-44] days; P < 0.001).

CONCLUSIONS

Patients undergoing pancreatic resection at pancreatic head portion should follow a postoperative diet, and postoperative glucose levels should be strictly regulated.

Locally advanced pancreatic cancer: a reliable contraindication to resection in the modern era?

BACKGROUND

The aim of this study is to present radiologically designated LAPC found to be resectable upon surgical exploration and evaluate the outcomes of such resections.

METHODS

Sequential LAPC patients between 2013 and 2019 were staged and underwent resection were included in the analysis of both perioperative and long-term outcomes.

RESULTS

Twenty-eight patients with radiologically-designated LAPC underwent surgical resection after chemotherapy with a median follow-up of 31.7 m,75% underwent pancreaticoduodenectomy. The margin positivity and local recurrence rates were 21.4% and 35.7%, respectively. When compared to the 30 BRPC controls, the LAPC group had a higher rates of an arterial resection (11vs.1; p = 0.002), but the groups were similar with regard to all other preoperative and intraoperative variables (p < 0.05). Perioperative morbidity rates were similar (25.9%vs21.4%; p = 0.53). The LAPC and BRPC groups were also equivalent with respect to median recurrence-free survival (9.0mo; 95%CI 6.3, 11.7vs.8.3mo; 95%CI 5.4, 11.2) and median overall survival (19.9mo; 95%CI 17.0, 22.7 vs. 19.9mo; 95%CI 14.8, 25.1), respectively.

CONCLUSION

Despite a radiologic designation of locally advanced pancreatic cancer, certain subtypes of LAPC warrant surgical exploration provided the operative surgeon is prepared for major arterial and/or venous resection. Pancreatectomy in these patients has acceptable morbidity and oncologic outcomes, similar to patients who are radiologically borderline resectable.

Preoperative Nutritional Optimization of the Oncology Patient: A Scoping Review

BACKGROUND

Malnutrition is common among patients with cancer and is a known risk factor for poor postoperative outcomes; however, preoperative nutritional optimization guidelines are lacking in this high-risk population. The objective of this study was to review the evidence regarding preoperative nutritional optimization of patients undergoing general surgical operations for the treatment of cancer.

METHODS

A literature search was performed across the Ovid (MEDLINE), Cochrane Library (Wiley), Embase (Elsevier), CINAHL (EBSCOhost), and Web of Science (Clarivate) databases. Eligible studies included randomized clinical trials, observational studies, reviews, and meta-analyses published between 2010 and 2020. Included studies evaluated clinical outcomes after preoperative nutritional interventions among adult patients undergoing surgery for gastrointestinal cancer. Data extraction was performed using a template developed and tested by the study team.

RESULTS

A total of 5,505 publications were identified, of which 69 studies were included for data synthesis after screening and full text review. These studies evaluated preoperative nutritional counseling, protein-calorie supplementation, immunonutrition supplementation, and probiotic or symbiotic supplementation.

CONCLUSIONS

Preoperative nutritional counseling and immunonutrition supplementation should be considered for patients undergoing surgical treatment of gastrointestinal malignancy. For malnourished patients, protein-calorie supplementation should be considered, and for patients undergoing colorectal cancer surgery, probiotics or symbiotic supplementation should be considered.

Optimizing Patient Selection for Irreversible Electroporation of Locally Advanced Pancreatic Cancer: Analyses of Survival

Background

Irreversible electroporation (IRE) has emerged as a viable consolidative therapy after induction chemotherapy, in which this combination has improved overall survival of locally advanced pancreatic cancer (LAPC). Optimal timing and patient selection for irreversible electroporation remains a clinically unmet need. The aim of this study was to investigate preoperative factors that may assist in predicting progression-free and overall survival following IRE.

Methods

A multi-institutional, prospectively maintained database was reviewed for patients with LAPC treated with induction chemotherapy followed by open-technique irreversible electroporation from 7/2015-5/2019. RECIST 1.1 criteria were used to assess tumor response and radiological progression. Overall survival (OS) and progression-free survival (PFS) were recorded. Survival analyses were performed using Kaplan Meier and Cox multivariable regression analyses.

Results

187 LAPC patients (median age 62 years range, 21 – 91, 65% men, 35% women) were treated with IRE. Median PFS was 21.7 months and median OS from diagnosis was 25.5 months. On multivariable analysis, age ≤ 61 (HR 0.41, 95%CI 0.21-0.78, p<0.008) and no prior radiation (HR 0.49, 95%CI 0.26-0.94, p=0.03) were positive predictors of OS after IRE. Age ≤ 61(HR 0.53, 95%CI, 0.28-.99, p=0.046) and FOLFIRINOX followed by gemcitabine/abraxane induction chemotherapy (HR 0.37,95%CI 0.15-0.89, p=0.027) predicted prolonged PFS after IRE. Abnormal CA19-9 values at the time of surgery negatively impacted both OS (HR 2.46, 95%CI 1.28-4.72, p<0.007) and PFS (HR 2.192, 95%CI 1.143-4.201, p=0.018) following IRE.

Conclusions

Age, CA 19-9 response, avoidance of pre-IRE radiation, and FOLFIRINOX plus gemcitabine/abraxane induction chemotherapy are prominent factors to consider when referring or selecting LAPC patients to undergo IRE.

Neoadjuvant treatment: A window of opportunity for nutritional prehabilitation in patients with pancreatic ductal adenocarcinoma

Patients affected by pancreatic ductal adenocarcinoma (PDAC) frequently present with advanced disease at the time of diagnosis, limiting an upfront surgical approach. Neoadjuvant treatment (NAT) has become the standard of care to downstage non-metastatic locally advanced PDAC. However, this treatment increases the risk of a nutritional status decline, which in turn, may impact therapeutic tolerance, postoperative outcomes, or even prevent the possibility of surgery. Literature on prehabilitation programs on surgical PDAC patients show a reduction of postoperative complications, length of hospital stay, and readmission rate, while data on prehabilitation in NAT patients are scarce and randomized controlled trials are still missing. Particularly, appropriate nutritional management represents an important therapeutic strategy to promote tissue healing and to enhance patient recovery after surgical trauma. In this regard, NAT may represent a new interesting window of opportunity to implement a nutritional prehabilitation program, aiming to increase the PDAC patient's capacity to complete the planned therapy and potentially improve clinical and survival outcomes. Given these perspectives, this review attempts to provide an in-depth view of the nutritional derangements during NAT and nutritional prehabilitation program as well as their impact on PDAC patient outcomes.

Implementation of Prehabilitation for Major Abdominal Surgery and Head and Neck Surgery: a Simplified Seven-Day Protocol

PURPOSE

The aim of this prospective trial was to assess the compliance of a prehabilitation protocol on post-operative outcome after major abdominal and head and neck surgery.

METHODS

A single-arm, prospective 7-day intervention trial was approved by our local IRB for patients undergoing major abdominal and head-and-neck (H&N) surgery from 8/2018 to 3/2019. This was a 7-day intervention trial at the time of pre-admission testing to assess compliance for pulmonary, nutritional, and physical activity prior to surgery.

RESULTS

Seventy-six patients were enrolled in this compliance with IS use that was 85%, with a median of 2200 cc (range 1500-2500cc), pre-operative nutritional drink (89.5%), and chlorhexidine gluconate use was 92%. Ambulation/step compliance was only 32 patients (44%), with median steps of 7500 (range 400-15,000). Compared with the non-prehabilitation patients, we found significant improvement in immediate post-operative mobility (OR 0.73, 95% CI 0.46-0.97, p = 0.04), and improvement in prevention of pulmonary morbidity (OR 0.82, 95% CI 0.23-1.18, p = 0.07) was observed in the prehabilitation group. No significant difference in overall infectious complications (18% vs 27%), surgical site infections (14% vs 22%), length of stay (median 6 days vs 6), or readmissions (18% vs 22%).

CONCLUSIONS

A simple 7-day prehabilitation protocol at the time of pre-admission testing is feasible with a high degree of compliance regardless of a patient's disease type, education, or socioeconomic background.

Diet and Exercise Interventions in Patients With Pancreatic Cancer: A Scoping Review

ABSTRACT

Diet and exercise interventions may help reverse malnutrition and muscle wasting common in pancreatic cancer. We performed a scoping review to identify the knowledge gaps surrounding diet and exercise interventions. We searched PubMed, Scopus, Cumulative Index to Nursing and Allied Health Literature, Embase, ProQuest Theses and Dissertations, and Google Scholar using the umbrella terms of "pancreatic cancer," "diet/nutrition," and "exercise." Included were articles reporting on ambulatory adults with diagnosed pancreatic cancer. Excluded were studies examining prevention and/or risk, animal, or cell lines. Of the 15,708 articles identified, only 62 met the final inclusion criteria. Almost half of the articles were randomized controlled studies (n = 27). Most studies were from the United States (n = 20). The majority examined dietary interventions (n = 41), with 20 assessing the use of omega-3 fatty acids. Exercise interventions were reported in 13 studies, with 8 examining a diet and exercise intervention. Most studies were small and varied greatly in terms of study design, intervention, and outcomes. We identified 7 research gaps that should be addressed in future studies. This scoping review highlights the limited research examining the effect of diet and exercise interventions in ambulatory patients with pancreatic cancer.

Dietary Amino Acids and Immunonutrition Supplementation in Cancer-Induced Skeletal Muscle Mass Depletion: A Mini-Review

Cancer patients display systemic inflammation, which leads to an increase in protein catabolism, thus promoting the release of free amino acids to further support metabolism and remodelling of muscle proteins. Inflammation associated with tumor growth leads to malnutrition, a factor that increases the risk of developing cachexia. With cancer-induced cachexia, nutritional interventions have gained traction as a preventative method to manage this condition. Currently, cancer consensus recommendations suggest a protein intake above 1.0 g/kg.day-1 up to 2.0 g/k.day-1 for cancer patients, although an ideal amount for some amino acids in isolation has yet to be determined. Due to controversy in the literature regarding the benefits of the biochemical mechanisms of various muscle mass supplements, such as L-leucine (including whey protein and BCAA), β-hydroxy-beta-methyl butyrate (HMβ), arginine, glutamine and creatine, several studies have carefully examined their effects. L-leucine and its derivatives appear to regulate protein synthesis by direct or indirect activation of the mTORC1 pool of kinases, further promoting muscle protein balance. Arginine and glutamine may act by reducing inflammation and infection progression, thus promoting improvements in food intake. Creatine exerts anabolic activity, acting as an immediate energy substrate to support muscle contraction further increasing lean mass, mainly due to greater water uptake by the muscle. In this narrative review, we highlighted the main findings regarding protein consumption and amino acids to mitigate cancer-induced skeletal muscle depletion.

Immunometabolism: new insights and lessons from antigen-directed cellular immune responses

Modulation of immune responses by nutrients is an important area of study in cellular biology and clinical sciences in the context of cancer therapies and anti-pathogen-directed immune responses in health and disease. We review metabolic pathways that influence immune cell function and cellular persistence in chronic infections. We also highlight the role of nutrients in altering the tissue microenvironment with lessons from the tumor microenvironment that shapes the quality and quantity of cellular immune responses. Multiple layers of biological networks, including the nature of nutritional supplements, the genetic background, previous exposures, and gut microbiota status have impact on cellular performance and immune competence against molecularly defined targets. We discuss how immune metabolism determines the differentiation pathway of antigen-specific immune cells and how these insights can be explored to devise better strategies to strengthen anti-pathogen-directed immune responses, while curbing unwanted, non-productive inflammation.

Effects of Immunonutrition on Comprehensive Complication Index in Patients Undergoing Pancreatoduodenectomy

Background and objectives: Immunonutrition is recommended by enhanced recovery after surgery in patients undergoing pancreatoduodenectomy for 5-7 days perioperatively as it may reduce the rate of infectious complications. However, data on effect of immunonutrition on the overall complication rate are contradictory and it is not clear, which groups of patients benefit most. The aims of this study are to evaluate the effects of immunonutrition on the overall complication rate and the rate of severe and/or multiple complications in patients with pancreatic tumours stratified according to final histological diagnosis-patients with pancreatic ductal adenocarcinoma (PDAC) vs. other tumours-and nutritional state, using more sensitive Comprehensive Complication Index. Materials and Methods: Seventy consecutive patients scheduled for pancreatoduodenectomy because of pancreatic tumours were randomised into immunonutrition vs. control groups and stratified according to final histological diagnosis and nutritional status. Surgical outcomes were assessed postoperatively using Clavien-Dindo classification (CDC) and Comprehensive Complication Index (CCI). Results: No significant differences in the overall complication rates in immunonutrition vs. control, patients with malnutrition vs. no malnutrition, PDAC vs. other pancreatic tumours groups were detected. However, significant differences in the rates of severe and/or multiple complications in immunonutrition vs. control groups and in PDAC patients segregated according to immunonutrition were obtained using CCI. Conclusions: Patients with PDAC may experience greater benefits of immunonutrition as compared to patients with benign pancreatic diseases or less aggressive tumours, while nutritional status was not a determining factor for the efficacy of immunonutrition.

Postoperative complication rate and survival of patients with gastric cancer undergoing immunonutrition: A retrospective study

OBJECTIVES

This study aimed to evaluate the effect of preoperative immunonutrition on the rate of postoperative complication and survival of patients with gastric cancer.

METHODS

A retrospective cohort was formed after data collection of patients hospitalized with gastric cancer. Postoperative complications classified according to the Clavien-Dindo classification system, length of hospital stay, readmissions, and rates of survival at 6 mo, 1 y, and 5 y were analyzed. A χ² or Fisher's exact test, Student or Mann-Whitney t test, and Kaplan-Meier and Cox regressions were used in the statistical analysis.

RESULTS

A total of 164 patients were included in the study, with 56 patients assigned to the immunonutrition group and 108 to the conventional group. There were no significant differences in postoperative complications between the immunonutrition and conventional groups (51.8% versus 58.3%; P = 0.423). The most frequent complications were fistula and surgical wound infection. Length of hospital stay did not differ between the groups (median of 7.0 d: P = 0.615) and the presence of readmissions did not differ either (12.5% versus 15.7%; P = 0.648). In the multivariate Cox regression, in a pooled model for group, age, sex, body mass index, Charlson comorbidity index, staging, neoadjuvant chemotherapy, and type of surgery, there was a significant difference in survival rates at 6 mo (P = 0.011), 1 y (P = 0.006), and 5 y (P < 0.001).

CONCLUSIONS

Preoperative immunonutrition in patients with gastric cancer did not reduce postoperative complications or length of hospital stay. More studies are needed to confirm the benefit of immunonutriton supplementation for overall survival when associated with other protective factors.

Influence of Pulsed Electric Fields and Mitochondria-Cytoskeleton Interactions on Cell Respiration

Pulsed electric fields with microsecond pulse width (μsPEFs) are used clinically; namely, irreversible electroporation/Nanoknife is used for soft tissue tumor ablation. The μsPEF pulse parameters used in irreversible electroporation (0.5-1 kV/cm, 80-100 pulses, ∼100 μs each, 1 Hz frequency) may cause an internal field to develop within the cell because of the disruption of the outer cell membrane and subsequent penetration of the electric field. An internal field may disrupt voltage-sensitive mitochondria, although the research literature has been relatively unclear regarding whether such disruptions occur with μsPEFs. This investigation reports the influence of clinically used μsPEF parameters on mitochondrial respiration in live cells. Using a high-throughput Agilent Seahorse machine, it was observed that μsPEF exposure comprising 80 pulses with amplitudes of 600 or 700 V/cm did not alter mitochondrial respiration in 4T1 cells measured after overnight postexposure recovery. To record alterations in mitochondrial function immediately after μsPEF exposure, high-resolution respirometry was used to measure the electron transport chain state via responses to glutamate-malate and ADP and mitochondrial membrane potential via response to carbonyl cyanide-p-trifluoromethoxyphenylhydrazone. In addition to measuring immediate mitochondrial responses to μsPEF exposure, measurements were also made on cells permeabilized using digitonin and those with compromised cytoskeleton due to actin depolymerization via treatment with the drug latrunculin B. The former treatment was used as a control to tease out the effects of plasma membrane permeabilization, whereas the latter was used to investigate indirect effects on the mitochondria that may occur if μsPEFs impact the cytoskeleton on which the mitochondria are anchored. Based on the results, it was concluded that within the pulse parameters tested, μsPEFs alone do not hinder mitochondrial physiology but can be used to impact the mitochondria upon compromising the actin. Mitochondrial susceptibility to μsPEF after actin depolymerization provides, to our knowledge, a novel avenue for cancer therapeutics.

The Impact of Preoperative Immune Modulating Nutrition on Outcomes in Patients Undergoing Surgery for Gastrointestinal Cancer: A Systematic Review and Meta-analysis

OBJECTIVE

To define the influence of preoperative immune modulating nutrition (IMN) on postoperative outcomes in patients undergoing surgery for gastrointestinal cancer.

BACKGROUND

Although studies have shown that perioperative IMN may reduce postoperative infectious complications, many of these have included patients with benign and malignant disease, and the optimal timing of such an intervention is not clear.

METHODS

The Embase, Medline, and Cochrane databases were searched from 2000 to 2018, for prospective randomized controlled trials evaluating preoperative oral or enteral IMN in patients undergoing surgery for gastrointestinal cancer. The primary endpoint was the development of postoperative infectious complications. Secondary endpoints included postoperative noninfectious complications, length of stay, and up to 30-day mortality. The analysis was performed using RevMan v5.3 software.

RESULTS

Sixteen studies reporting on 1387 patients (715 IMN group, 672 control group) were included. Six of the included studies reported on a mixed population of patients undergoing all gastrointestinal cancer surgery. Of the remaining, 4 investigated IMN in colorectal cancer surgery, 2 in pancreatic surgery, and another 2 in patients undergoing surgery for gastric cancer. There was 1 study each on liver and esophageal cancer. The formulation of nutrition used in all studies in the treated patients was Impact (Novartis/Nestlé), which contains ω-3 fatty acids, arginine, and nucleotides. Preoperative IMN in patients undergoing surgery for gastrointestinal cancer reduced infectious complications [odds ratio (OR) 0.52, 95% confidence interval (CI) 0.38-0.71, P < 0.0001, I = 16%, n = 1387] and length of hospital stay (weighted mean difference -1.57 days, 95% CI -2.48 to -0.66, P = 0.0007, I = 34%, n = 995) when compared with control (isocaloric isonitrogeneous feed or normal diet). It, however, did not affect noninfectious complications (OR 0.98, 95% CI 0.73-1.33, P = 0.91, I = 0%, n = 1303) or mortality (OR 0.55, 95% CI 0.18-1.68, P = 0.29, I = 0%, n = 955).

CONCLUSION

Given the significant impact on infectious complications and a tendency to shorten length of stay, preoperative IMN should be encouraged in routine practice in patients undergoing surgery for gastrointestinal cancer.

Characterization of Conductivity Changes During High-Frequency Irreversible Electroporation for Treatment Planning

For irreversible-electroporation (IRE)-based therapies, the underlying electric field distribution in the target tissue is influenced by the electroporation-induced conductivity changes and is important for predicting the treatment zone.

OBJECTIVE

In this study, we characterized the liver tissue conductivity changes during high-frequency irreversible electroporation (H-FIRE) treatments of widths 5 and 10 μs and proposed a method for predicting the ablation zones.

METHODS

To achieve this, we created a finite-element model of the tissue treated with H-FIRE and IRE pulses based on experiments conducted in an in-vivo rabbit liver study. We performed a parametric sweep on a Heaviside function that captured the tissue conductivity versus electric field behavior to yield a model current close to the experimental current during the first burst/pulse. A temperature module was added to account for the current increase in subsequent bursts/pulses. The evolution of the electric field at the end of the treatment was overlaid on the experimental ablation zones determined from hematoxylin and eosin staining to find the field thresholds of ablation.

RESULTS

Dynamic conductivity curves that provided a statistically significant relation between the model and experimental results were determined for H-FIRE. In addition, the field thresholds of ablation were obtained for the tested H-FIRE parameters.

CONCLUSION

The proposed numerical model can simulate the electroporation process during H-FIRE.

SIGNIFICANCE

The treatment planning method developed in this study can be translated to H-FIRE treatments of different widths and for different tissue types.