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© 2022 Wolters Kluwer Health, Inc. All rights reserved.Objective: To assess postoperative 90-day outcomes after minimally invasive (laparoscopic/robot-assisted) total pancreatectomy (MITP) in selected patients versus open total pancreatectomy (OTP) among European centers. Background: Minimally invasive pancreatic surgery is becoming increasingly popular but data on MITP are scarce and multicenter studies comparing outcomes versus OTP are lacking. It therefore remains unclear if MITP is a valid alternative. Methods: Multicenter retrospective propensity-score matched study including consecutive adult patients undergoing MITP or OTP for all indications at 16 European centers in 7 countries (2008-2017). Patients after MITP were matched (1:1, caliper 0.02) to OTP controls. Missing data were imputed. The primary outcome was 90-day major morbidity (Clavien-Dindo ≥3a). Secondary outcomes included 90-day mortality, length of hospital stay, and survival. Results: Of 361 patients (99MITP/262 OTP), 70 MITP procedures (50 laparoscopic, 15 robotic, 5 hybrid) could be matched to 70 OTP controls. After matching, MITP was associated with a lower rate of major morbidity (17% MITP vs. 31% OTP, P = 0.022). The 90-day mortality (1.4% MITP vs. 7.1% OTP, P = 0.209) and median hospital stay (17 [IQR 11-24] MITP vs. 12 [10-23] days OTP, P = 0.876) did not differ significantly. Among 81 patients with PDAC, overall survival was 3.7 (IQR 1.7-N/A) versus 0.9 (IQR 0.5-N/ A) years, for MITP versus OTP, which was nonsignificant after stratification by T-stage. Conclusion: This international propensity score matched study showed that MITP may be a valuable alternative to OTP in selected patients, given the associated lower rate of major morbidity.

Background: Genetic evaluation is essential in assessing colorectal cancer (CRC) and colorectal liver metastasis (CRLM). The aim of this study was to determine the pragmatic value of KRAS on oncological outcomes after CRLM according to the ESMO recommendations and to query whether it is necessary to request KRAS testing in each situation. Methods: A retrospective cohort of 126 patients who underwent surgery for hepatic resection for CRLM between 2009 and 2020 were reviewed. The patients were divided into three categories: wild-type KRAS, mutated KRAS and impractical KRAS according to their oncological variables. The impractical (not tested) KRAS group included patients with metachronous tumours and negative lymph nodes harvested. Disease-free survival (DFS), overall survival (OS) and hepatic recurrence-free survival (HRFS) were calculated by the Kaplan–Meier method, and a multivariable analysis was conducted using the Cox proportional hazards regression model. Results: Of the 108 patients identified, 35 cases had KRAS wild-type, 50 cases had a KRAS mutation and the remaining 23 were classified as impractical KRAS. Significantly longer medians for OS, HRFS and DFS were found in the impractical KRAS group. In the multivariable analyses, the KRAS mutational gene was the only variable that was maintained through OS, HRFS and DFS. For HRFS (HR: 13.63; 95% confidence interval (CI): 1.35–100.62; p = 0.010 for KRAS), for DFS (HR: 10.06; 95% CI: 2.40–42.17; p = 0.002 for KRAS) and for OS (HR: 4.55%; 95% CI: 1.37–15.10; p = 0.013). Conclusion: Our study considers the possibility of unnecessary KRAS testing in patients with metachronous tumours and negative lymph nodes harvested. Combining the genetic mutational profile (i.e., KRAS in specific cases) with tumour characteristics helps patient selection and achieves the best prognosis after CRLM resection.

[EN] Microwave (MWA) and radiofrequency ablation (RFA) are main ablative techniques for hepatocellular carcinoma (HCC) and colorectal liver metastasis (MT). This randomized phase 2 clinical trial compares the effectiveness of MWA and RFA as well as morphology of corresponding ablation zones. HCC and MT patients with 1.5-4 cm tumors, suitable for ablation, were randomized into MWA or RFA Groups. The primary endpoint was short-to-long diameter ratio of ablation zone (SLR). Primary technical success (TS) and a cumulative local tumor progression (LTP) after a median 2-year follow-up were compared. Between June 2015 and April 2020, 82 patients were randomly assigned (41 patients per group). For the per-protocol analysis, five patients were excluded. MWA created larger ablation zones than RFA (p = 0.036) although without differences in SLR (0.5 for both groups, p = 0.229). The TS was achieved in 98% (46/47) and 90% (45/50) (p = 0.108), and LTP was observed in 21% (10/47) vs. 12% (6/50) (OR 1.9 [95% CI 0.66-5.3], p = 0.238) of tumors in MWA vs. RFA Group, respectively. Major complications were found in 5 cases (11%) vs. 2 cases (4%), without statistical significance. MWA and RFA show similar SLR, effectiveness and safety in liver tumors between 1.5 and 4 cm., This work was supported by a grant for medical research from Spanish Government (FIS-PI12/00799) and by the Spanish Ministerio de Ciencia, Innovacion y Universidades under "Programa Estatal de I+D+i Orientada a los Retos de la Sociedad", Grant RTI2018-094357-B-C21.

[EN] Background Whereas the usefulness of radiofrequency (RF) energy as haemostatic method in liver surgery has become well established in the last decades, its intentional application on resection margins with the aim of reducing local recurrence is still debatable. Our goal was to compare the impact of an additional application of RF energy on the top of the resection surface, namely additional margin coagulation (AMC), on local recurrence (LR) when subjected to a subcentimeter margin. Methods We retrospectively analyzed 185 patients out of a whole cohort of 283 patients who underwent radical hepatic resection with subcentimetric margin. After propensity score adjustment, patients were classified into two balanced groups according to whether RF was applied or not. Results No significant differences were observed within groups in baseline characteristics after PSM adjustment. The LR rate was significantly higher in the Control than AMC Group: 12 patients (14.5%) vs. 4 patients (4.8%) (p = 0.039). The estimated 1, 3, and 5-year LR-free survival rates of patients in the Control and AMC Group were: 93.5%, 86.0%, 81.0% and 98.8%, 97.2%, 91.9%, respectively (p = 0.049). Univariate Cox analyses indicated that the use of the RF applicator was significantly associated with lower LR (HR = 0.29, 95% confidence interval 0.093¿0.906, p = 0.033). The Control Group showed smaller coagulation widths than the AMC group (p < 0.001). Conclusions An additional application of RF on the top of the resection surface is associated with less local hepatic recurrence than the use of conventional techniques., This work was partially supported by the Spanish Ministerio de Ciencia, Innovación y Universidades under "Programa Estatal de I+D+i Orientada a los Retos de la Sociedad", Grants Nº "RTI2018-094357-B-C21" and "RTI2018-094357-B-C22"

Oligometastatic disease is a relatively new concept that refers to an intermediate stage between disseminated and localized cancer. Most frequent locations for colorectal metastasis are lung and liver. We present an a typical case of an 85-year-old woman who was diagnosed with a low-grade adenocarcinoma in left colon; she underwent a left laparoscopic hemicolectomy which resulted in a stage IIIb. After 24 months of follow-up, an increase of carcinoembryonic antigen (CEA) leads to the diagnosis of two metastatic lesions in two uncommon locations: spleen and myometrium. Stepwise surgical resection of both lesions was performed without complications. Spleen and uterus are organs that are rarely affected in colorectal cancer, the affection of both organs being even more infrequent. Despite the atypicality, surgical treatment is a valid strategy in this case of oligometastatic disease, which enables the disease-free survival of the patients.

OBJECTIVE: The aim of this study was to evaluate whether neoadjuvant therapy (NAT) critically influenced microscopically complete resection (R0) rates and long-term outcomes for patients with pancreatic ductal adenocarcinoma who underwent pancreatoduodenectomy (PD) with portomesenteric vein resection (PVR) from a diverse, world-wide group of high-volume centers. SUMMARY OF BACKGROUND DATA: Limited size studies suggest that NAT improves R0 rates and overall survival compared to upfront surgery in R/BR-PDAC patients. METHODS: This multicenter study analyzed consecutive patients with R/BR-PDAC who underwent PD with PVR in 23 high-volume centers from 2009 to 2018. RESULTS: Data from 1192 patients with PD and PVR were collected and analyzed. The median age was 68 [interquartile range (IQR) 60-73] years and 52% were males. Some 186 (15.6%) and 131 (10.9%) patients received neoadjuvant chemotherapy (NAC) alone and neoadjuvant chemoradiotherapy, respectively. The R0/R1/R2 rates were 57%, 39.3%, and 3.2% in patients who received NAT compared to 46.6%, 49.9%, and 3.5% in patients who did not, respectively (P =0.004). The 1-, 3-, and 5-year OS in patients receiving NAT was 79%, 41%, and 29%, while for those that did not it was 73%, 29%, and 18%, respectively (P

Background: To demonstrate the efficacy of radiofrequency for pancreatic stump closure in reducing the incidence of postoperative pancreatic fistula (POPF) in distal pancreatectomy (DP) compared with mechanical transection methods. Despite all the different techniques of pancreatic stump closure proposed for DP, best practice for avoiding POPF remains an unresolved issue, with an incidence of up to 30% regardless of center volume or surgical expertise.Methods: DP was performed in a cohort of patients by applying radiofrequency to stump closure (RF Group) and compared with mechanical closure (Control Group). A propensity score (PS) matched cohort study was carried out to minimize bias from nonrandomized treatment assignment. Cohorts were matched by PS accounting for factors significantly associated with either undergoing RF transection or mechanical closure through logistic regression analysis. The primary end-point was the incidence of clinically relevant POPF (CR-POPF).Results: Of 89 patients included in the whole cohort, 13 case patients from the RF- Group were 1:1 matched to 13 control patients. In both the first independent analysis of unmatched data and subsequent adjustment to the overall propensity score-matched cohort, a higher rate of CR-POPF in the Control Group compared with the RF-Group was detected (25.4% vs. 5.3%, p=0.049 and 53.8% vs. 0%; p = 0.016 respectively). The RF Group showed better outcomes in terms of readmission rate (46.2% vs 0%, p=0.031). No significant differences were observed in terms of mortality, major complications (30.8% vs 0%, p=0.063) or length of hospital stay (5.7 vs 5.2 days, p=0.89).Conclusion: Findings suggest that the RF-assisted technique is more efficacious in reducing CR-POPF than mechanical pancreatic stump closure.

The aim of this retrospective study was thus to evaluate postoperative morphological changes in the remnant pancreas after pancreaticoduodenectomy (PD) associated with postoperative pancreatic fistula (POPF). Fifty-one patients subjected to PD were enrolled in the study and allocated into 2 groups according to the presence (n = 16) or absence of POPF (n = 35). A morphological evaluation of the pancreas was conducted for up to a 20 months follow-up on CT scans and compared between groups. No significant differences were observed in morphology between the groups at the different preoperative and PO intervals, regardless of the clinical relevance of the POPF or POPF grade. However, in the overall patient analysis we observed a significant reduction of the entire pancreas over time. In fact, thickness decreased 0.4 mm/month, length 1.2 mm/month and volume 1.17 cm3/month over the PO. The impact of age, POPF, type of anastomosis, surgical technique and PO follow-up (time) was evaluated in a multivariate analysis using the general linear model, but only PO follow-up had a significant influence on the final model (p

[EN] Radiofrequency energy has been used both experimentally and clinically to manage the pancreatic remnant after distal pancreatectomies. Our goal was to determine whether endoluminal radiofrequency (RF) ablation of the main pancreatic duct in large animals would be more efficient than glue occlusion as an exocrine pancreatic atrophy-inducing procedure. Thirty-four Landrace pigs were assigned to either the transpapilar (n = 16) or transection (n = 18) groups. The transection implied the pancreas neck was severed. In each of these groups the remaining distal pancreatic duct was occluded either by RF or by glue. In the transpapilar group complete atrophy was observed in all the RF cases, while atrophy was incomplete in all the members of the glue subgroup. The failure rate of the main pancreatic duct (usually expressed by a pseudocyst) in the transection groups was dramatically higher in the glue subgroup than the RF subgroups (9 out of 9 and 1 out of 9, respectively) and postoperative mortality occurred only in the glue subgroup (3 out of 9). These results show the superiority of endoluminal RF ablation over glue for main pancreatic duct occlusion, as seen by the degree of atrophy and fewer postoperative pancreatic fistulas., This work was supported by the Spanish Ministerio de Economia, Industria y Competitividad under the "Plan Estatal de Investigacion, Desarrollo e Innovacion Orientada a los Retos de la Sociedad" Grant TEC2014-52383-C3-R (TEC2014-52383-C3-1-R and TEC2014-52383-C3-3-R). Elzbieta Ewertowska has a Predoctoral Grant (BES-2015-073285) from the Ministry of Economy, Industry and Competitiveness (Government of Spain).

PURPOSE: To study the safety and efficacy of ultrasound-guided percutaneous radiofrequency ablation (RFA) as local treatment for breast cancer and to intraoperatively evaluate the margin status after RFA in comparison with lumpectomy. MATERIAL and METHODS: Preliminary in vitro RF ablation experimentation with two mastectomy specimens was performed to test the electrode, practice the ultrasound technique and evaluate the macroscopic and microscopic effects of RF. Then, aprospective, randomized open-label phase II clinical trial (NCT02281812) was conducted in a single institution from 2013-2017. Forty subjects, mean age 64 (range 46-86), with ductal infiltrating carcinoma of the breast ≤2 cm were randomly assigned to RFA plus lumpectomy or lumpectomy alone. Margin status, tumor cell viability (TCV) after RFA (by nicotinamide adenine dinucleotide (NADH) and Cytokeratin 18 (CK18) staining), adverse events and local recurrences were evaluated by univariable and multivariable analyses (SPSS statistical software). RESULTS: In the experimental design with mastectomies, the only procedural complication was a skin burn at the entrance site of the electrodes. We learned that the tip of the electrodes should cut cross the tumor by at least 10mm. The clinical trial includes two groups: study group (n=20) and control group (n=20). NADH and CK18 staining demonstrated absence of TCV after RFA with at least one of the two techniques. The percentage of intraoperatively affected surgical margins was higher in the control group although local adverse effects after surgery was higher in the RFA treatment arm. Three study subjects presented local infection (two had partial irradiation of the breast) and none in the control group. Median follow up was 25 months (range 1–83). No recurrence or second surgery was required during the study period. Outcomes RFA group (n = 20)Control group (n=20)p valueSpecimen weight (median, gr)42 (24-80)27 (11-60)0.004Specimen volume (median, ml)369 (259-847)201 (100-602)0.004Positive margin (intraoperative)4/20 (20%)11/20 (55%)0.022Pathological size (median, mm)11.5 (5-20)10.5 (6-16)0.07Local Adverse effect8/20 (40%)1/20 (5%)0.01Breast Inflammation5/20 (25%)1/20 (5%)0.182Breast Infection3/20 (15%)0/20 (0%)0.23RFA: radiofrequency ablation. n=number of subjects CONCLUSION: RFA seems effective in the cases considered and could be more accurate than lumpectomy in terms of obtaining more free margins. Surgical excision associated with RFA leads to a higher amount of local adverse effects, especially if combined with partial irradiation of the breast. RFA could be considered as a less invasive treatment in tumors smaller than 20 mm; however, this warrants further investigation. Citation Format: Garcia-Tejedor A, Guma A, Soler T, Valdivieso A, Petit A, Contreras N, Chappuis CG, Falo C, Pernas S, Anselem A, Fernandez-Montoli E, Pla MJ, Burdio F, Ponce J. Is radiofrequency ablation better than lumpectomy for margin status in breast cancer? Results of a randomized clinical trial [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P3-13-07.

[EN] Purpose Multiple attempts have been made to manage the pancreatic stump and the pancreatic duct in order to reduce the rate of postoperative pancreatic fistula (POPF) after pancreaticoduodenectomy (PD), however radiofrequency-based technologies could help to achieve this goal. Previous encouraging clinical and experimental results support the use of endoluminal thermal ablation (ETHA) of the main pancreatic duct to reduce pancreatic exocrine secretion and hence POPF. We here describe our initial clinical experience with ETHA of the main pancreatic duct in two cases at high risk of POPF. Methods Two cases underwent PD for malignancy with a high risk of POPF (adenocarcinoma, obese patients, surgical difficulties with heavy intraoperative blood loss, soft pancreas or walled-off pancreatitis and a tight small pancreatic main duct). In both cases, ETHA of the main pancreatic duct was conducted intraoperatively just before Blumgart-type pancreatic-jejunal anastomosis using a ClosureFast catheter (Medtronic, Mansfield, MA, USA) normally used for varicose vein treatment (therefore an off-label use). Results Although a clear radiological POPF was detected in the second case, the clinical postoperative course in both cases was uneventful. Little pancreatic fluid collected in the abdominal drainage with low levels of amylase enzyme, confirming low exocrine pancreatic function. No other procedure-related complications were detected. Conclusion Endoluminal thermal ablation of the main pancreatic duct may be a feasible and safe technique to reduce the adverse effects of POPF after PD., This work was supported by the Spanish Ministerio de Ciencia, Innovacion y Universidades under "Programa Estatal de IthornDthorni Orientada a los Retos de la Sociedad", Grants RTI2018-094357-B-C21 and RTI2018-094357-B-C22.

Background: Randomized trials have compared laparoscopic pancreatoduodenectomy (LPD) to open pancreatoduodenectomy (OPD) with conflicting results. An IPDMA may give more insight into the differences between LPD and OPD, and could identify high-risk subgroups. Methods: A systematic literature search was performed in the Pubmed, Embase, and the Cochrane library databases (October 2019). Out of 1410 studies, three randomized trials were identified. Primary outcome was major complications (Clavien-Dindo grade ≥ III). Subgroup analyses were performed for high-risk subgroups including patients with BMI of ≥25 kg/m2, pancreatic duct

Objective: The aim of this study was to establish clinically relevant outcome benchmark values using criteria for pancreatoduodenectomy (PD) with portomesenteric venous resection (PVR) from a low-risk cohort managed in high-volume centers. Summary Background Data: PD with PVR is regarded as the standard of care in patients with cancer involvement of the portomesenteric venous axis. There are, however, no benchmark outcome indicators for this population which hampers comparisons of patients undergoing PD with and without PVR resection. Methods: This multicenter study analyzed patients undergoing PD with any type of PVR in 23 high-volume centers from 2009 to 2018. Nineteen outcome benchmarks were established in low-risk patients, defined as the 75th percentile of the median outcome values of the centers (NCT04053998). Results: Out of 1462 patients with PD and PVR, 840 (58%) formed the benchmark cohort, with a mean age was 64 (SD11) years, 413 (49%) were females. Benchmark cutoffs, among others, were calculated as follows: Clinically relevant pancreatic fistula rate (International Study Group of Pancreatic Surgery): ≤14%; in-hospital mortality rate: ≤4%; major complication rate Grade≥3 and the CCI up to 6 months postoperatively: ≤36% and ≤26, respectively; portal vein thrombosis rate: ≤14% and 5-year survival for patients with pancreatic ductal adenocarcinoma: ≥9%. Conclusion: These novel benchmark cutoffs targeting surgical performance, morbidity, mortality, and oncological parameters show relatively inferior results in patients undergoing vascular resection because of involvement of the portomesenteric venous axis. These benchmark values however can be used to conclusively assess the results of different centers or surgeons operating on this high-risk group.

[EN] Pancreatic duct ligation (PDL) in the murine model has been described as an exocrine pancreatic atrophy-inducing procedure. However, its influence has scarcely been described on premalignant lesions. This study describes the histological changes of premalignant lesions and the gene expression in a well-defined model of pancreatic ductal adenocarcinoma by PDL. Selective ligation of the splenic lobe of the pancreas was performed in Ptf1a-Cre((+/ki)); K-ras LSLG12Vgeo((+/ki)) mice (PDL-Kras mice). Three experimental groups were evaluated: PDL group, controls and shams. The presence and number of premalignant lesions (PanIN 1-3 and Atypical Flat Lesions-AFL) in proximal (PP) and distal (DP) pancreas were studied for each group over time. Microarray analysis was performed to find differentially expressed genes (DEG) between PP and PD. Clinical human specimens after pancreaticoduodenectomy with ductal occlusion were also evaluated. PDL-Kras mice showed an intense pattern of atrophy in DP which was shrunk to a minimal portion of tissue. Mice in control and sham groups had a 7 and 10-time increase respectively of risk of high-grade PanIN 2 and 3 and AFL in their DP than PDL-Kras mice. Furthermore, PDL-Kras mice had significantly less PanIN 1 and 2 and AFL lesions in DP compared to PP. We identified 38 DEGs comparing PP and PD. Among them, several mapped to protein secretion and digestion while others such as Nupr1 have been previously associated with PanIN and PDAC. PDL in Ptf1a-Cre((+/ki)); K-ras LSLG12Vgeo((+/ki)) mice induces a decrease in the presence of premalignant lesions in the ligated DP. This could be a potential line of research of interest in some cancerous risk patients., This work was supported by the Spanish Ministerio de Economia, Industria y Competitividad under "Plan Estatal de Investigacion, Desarrollo e Innovacion Orientada a los Retos de la Sociedad", Grant No "RTI2018-094357-B-C22".

Accurate assessment of the vascular anatomy is a prerequisite of any pancreatic resection, since an unnoticed arterial injury in the context of a complex resection such as Whipple procedure, can seriously jeopardize patient’s safety. This article aims to describe an infrequent anatomic variant of a replaced right hepatic artery originating directly from the gastroduodenal artery and its potential implications for duodenopancreatectomy, as the gastroduodenal artery is routinely divided. We present here two different cases of this arterial abnormality identified during a Whipple procedure and its implications in each different setting. Preoperative identification of anatomical variations is essential for proficient surgical planning. Nevertheless, when detected during surgery, an meticulous dissection of the hepatoduodenal ligament is required to identify all the vascular relations in order to avoid irreversible damage.

Laparoscopic pancreatoduodenectomy (LPD) remains an extremely demanding surgery. The purpose of this study was to describe the learning curve required for its safe implementation.Fifty consecutive patients undergoing LPD were retrospectively reviewed. The learning curve was clustered into 4 groups: A, B and C (initial phase, n = 10 each) and D (consolidation phase, n = 20). Cumulative Sum (CUSUM) analysis was applied to operative time, conversion rate and severe postoperative complications.No significant differences were observed among groups and phases concerning specific and general postoperative complications, oncological outcomes or mortality. The conversion rate significantly reduced from 90% (9) in Group A to 40% (4) in Group C (p 0.01). Operative time was longer in the consolidation phase (median of 506 vs 437 min, p 0.01). Conversely, hospital stays were shorter during the consolidation phase (8 vs 15 days, p 0.01). CUSUM analysis identified 20-25cases as being enough to complete the learning curve if operative time and severe complications are analysed, while 40 cases would be needed for considering the conversion rate.The learning curve in LPD can be completed after 20-25 procedures. This information will help to design programmes for introducing new surgeons to this technique.

Objective:To compare perioperative outcomes of pancreatoduodenectomy (PD) performed through the laparoscopic route or by open surgery.Summary Background Data:Laparoscopic PD is being progressively performed in selected patients.Methods:An open-label single-center RCT was conducted between February 2

[EN] Purpose: To improve the computer modelling of radiofrequency ablation (RFA) by internally cooled wet (ICW) electrodes with added clinically oriented features. Methods: An improved RFA computer model by ICW electrode included: (1) a realistic spatial distribution of the infused saline, and (2) different domains to distinguish between healthy tissue, saline-infused tumour, and non-infused tumour, under the assumption that infused saline is retained within the tumour boundary. A realistic saline spatial distribution was obtained from an in vivo pig liver study. The computer results were analysed in terms of impedance evolution and coagulation zone (CZ) size, and were compared to the results of clinical trials conducted on 17 patients with the same ICW electrode. Results: The new features added to the model provided computer results that matched well with the clinical results. No roll-offs occurred during the 4-min ablation. CZ transversal diameter (4.10 +/- 0.19 cm) was similar to the computed diameter (4.16 cm). Including the tumour and saline infusion in the model involved (1) a reduction of the initial impedance by 10 - 20 ohm, (2) a delay in roll-off of 20 s and 70 - 100 s, respectively, and (3) 18 - 31% and 22 - 36% larger CZ size, respectively. The saline spatial distribution geometry was also seen to affect roll-off delay and CZ size. Conclusions: Using a three-compartment model and a realistic saline spatial distribution notably improves the match with the outcome of the clinical trials., This work was supported by the Spanish Ministerio de Economia, Industria y Competitividad under the "Plan Estatal de Investigacion, Desarrollo e Innovacion Orientada a los Retos de la Sociedad" Grant TEC2014-52383-C3-R (TEC2014-52383-C3-1-R and TEC2014-52383-C3-3-R). Elzbieta Ewertowska has a Predoctoral Grant (BES-2015-073285) from the Ministry of Economy, Industry and Competitiveness (Government of Spain).

Objectives To assess the minimally invasive surgery into the step-up approach procedures as a standard treatment for severe acute pancreatitis and comparing its results with those obtained by classical management. Methods Retrospective cohort study comparative with two groups treated over two consecutive, equal periods of time were defined: group A, classic management with open necrosectomy from January 2006 to June 2010; and group B, management with the step-up approach with minimally invasive surgery from July 2010 to December 2014. Results In group A, 83 patients with severe acute pancreatitis were treated, of whom 19 underwent at least one laparotomy, and in 5 any minimally invasive surgery. In group B, 81 patients were treated: minimally invasive surgery was necessary in 17 cases and laparotomy in 3. Among operated patients, the time from admission to first interventional procedures was significantly longer in group B (9 days vs. 18.5 days; p = 0.042). There were no significant differences in Intensive Care Unit stay or overall stay: 9.5 and 27 days (group A) vs. 8.5 and 21 days (group B). Mortality in operated patients and mortality overall were 50% and 18.1% in group A vs 0% and 6.2% in group B (p Conclusions The combination of the step-up approach and minimally invasive surgery algorithm is feasible and could be considered as the standard of treatment for severe acute pancreatitis. The mortality rate deliberately descends when it is used.

Irreversible electroporation is a novel tissue ablation technique which entails delivering intense electrical pulses to target tissue, hence producing fatal defects in the cell membrane. The present study numerically analyzes the potential impact of liver blood vessels on ablation by irreversible electroporation because of their influence on the electric field distribution. An anatomically realistic computer model of the liver and its vasculature within an abdominal section was employed, and blood vessels down to 0.4 mm in diameter were considered. In this model, the electric field distribution was simulated in a large series of scenarios (N = 576) corresponding to plausible percutaneous irreversible electroporation treatments by needle electrode pairs. These modeled treatments were relatively superficial (maximum penetration depth of the electrode within the liver = 26 mm) and it was ensured that the electrodes did not penetrate the vessels nor were in contact with them. In terms of total ablation volume, the maximum deviation caused by the presence of the vessels was 6%, which could be considered negligible compared to the impact by other sources of uncertainty. Sublethal field magnitudes were noticed around vessels covering volumes of up to 228 mm3. If in this model the blood was substituted by a liquid with a low electrical conductivity (0.1 S/m), the maximum volume covered by sublethal field magnitudes was 3.7 mm3 and almost no sublethal regions were observable. We conclude that undertreatment around blood vessels may occur in current liver ablation procedures by irreversible electroporation. Infusion of isotonic low conductivity liquids into the liver vasculature could prevent this risk. This work received financial support from the Spanish Government through grants TEC2010-17285, TEC2011-27133-C02, and TEC2014-52383-C3 (TEC2014-52383-C3-2) and from the European Commission through the Marie Curie IRG grant “TAMIVIVE” 256376.

In the open approach, pancreaticoduodenectomy (PD) continues to be a high-risk procedure with a high rate of severe complications and a global death-rate of 9.2% and 10.1% in some developed European countries, such as France and Germany, respectively (1,2). Most of reported volume-based outcome studies have found a strong inverse association between mortality and hospital volume. In a nationwide German hospital discharge data (2), risk-adjusted mortality of very-low-volume vs very-high-volume hospitals was 11.5% vs. 6.5%, respectively.

Irreversible electroporation (IRE) has gained attention as a new non-thermal therapy for ablation with important benefits in terms of homogeneous treatment and fast recovery. In this study, a new concept of high voltage generator is used, enabling irreversible electroporation treatment in large tissue volume using parallel plates. Unlike currently available generators, the proposed versatile structure enables delivering high-voltage high-current pulses. To obtain homogeneous results, 3-cm parallel-plates electrodes have also been designed and implemented. IRE ablation was performed on six female pigs at 2000 V/cm electric field, and the results were analysed after sacrifice three hours, three days and seven days after ablation. Histopathological and ultrastructural studies, including transmission and scanning electron microscopy, were carried out. The developed high-voltage generator has proved to be effective for homogeneous IRE treatment using parallel plates. The destruction of the membrane of the hepatocytes and the alterations of the membranes of the cellular organelles seem incompatible with cell death by apoptosis. Although endothelial cells also die with electroporation, the maintenance of vascular scaffold allows repairing processes to begin from the third day after IRE as long as the blood flow has not been interrupted. This study has opened new direction for IRE using high performance generators and highlighted the importance of taking into account ultrastructural changes after IRE by using electron microscopy analysis. This work was partly supported by the Spanish MINECO under Project TEC2016-78358-R and by the DGA-FSE. Authors would like to acknowledge the use of Servicio General de Apoyo a la Investigación-SAI, Universidad de Zaragoza.

[EN] Introduction: Endoluminal sealing of the pancreatic duct by glue or sutures facilitates the management of the pancreatic stump. Our objective was to develop a catheter-based alternative for endoluminal radiofrequency (RF) sealing of the pancreatic duct. Materials and methods: We devised a novel RF ablation technique based on impedance-guided catheter pullback. First, bench tests were performed on ex vivo models to tune up the technique before the in vivo study, after which endoluminal RF sealing of a similar to 10 cm non-transected pancreatic duct was conducted on porcine models using a 3 Fr catheter. After 30 days, sealing effectiveness was assessed by a permeability test and a histological analysis. Results: The RF technique was feasible in all cases and delivered similar to 5 W of power on an initial impedance of 308 +/- 60 ohm. Electrical impedance evolution was similar in all cases and provided guidance for modulating the pullback speed to avoid tissue sticking and achieve a continuous lesion. During the follow-up the animals rate of weight gain was significantly reduced (p < 0.05). Apart from signs of exocrine atrophy, no other postoperative complications were found. At necropsy, the permeability test failed and the catheter could not be reintroduced endoluminally, confirming that sealing had been successful. The histological analysis revealed a homogeneous exocrine atrophy along the ablated segment in all the animals. Conclusions: Catheter-based RF ablation could be used effectively and safely for endoluminal sealing of the pancreatic duct. The findings suggest that a fully continuous lesion may not be required to obtain complete exocrine atrophy., This work was supported by the Spanish Ministerio de Economia, Industria y Competitividad under "Plan Estatal de Investigacion, Desarrollo e Innovacion Orientada a los Retos de la Sociedad" (Grant TEC2014-52383-C3-R) and by the Spanish Ministerio de Ciencia, Innovacion y Universidades under "Programa Estatal de I+D+i Orientada a los Retos de la Sociedad" (Grant: RTI2018-094357-B-C21 and -C22). Elzbieta Ewertowska has a Predoctoral Grant (BES-2015-073285) from the Ministry of Economy, Industry and Competitiveness (Government of Spain). Also funding was received from Secretaria de Estado de Investigacion, Desarrollo e Innovacion.

Purpose To compare the safety and efficacy of US-guided percutaneous radiofrequency ablation (RFA) as a local treatment for breast cancer with that of lumpectomy. Materials and Methods A prospective, randomized open-label phase II clinical trial (clinicaltrials.gov identification number NCT02281812) was conducted in a single institution from 2013 to 2017. Women with invasive ductal carcinoma of the breast measuring 2 cm or smaller were randomly assigned to receive RFA or lumpectomy alone (control group). Margin status at surgery, tumor cell viability after RFA (with nicotinamide adenine dinucleotide [NADH] and cytokeratin 18 [CK18] staining), cosmetic results, adverse events, and local recurrences were evaluated with univariable and multivariable analyses. Results Forty subjects (20 in the RFA group and 20 in the lumpectomy group) were evaluated. The mean participant age was 64 years (range, 46-86 years). NADH and CK18 staining demonstrated absence of tumor cell viability after RFA with at least one of the two techniques. The surgical margins were positive in 11 of the 20 participants in the lumpectomy group (55%) and four of the 20 in the RFA group (20%) (P = .02). Median follow-up was 25 months (range, 1-83 months). Local breast inflammation after surgery was higher in the RFA group than in the lumpectomy group (40% [eight of 20 participants] vs 5% [one of 20 participants], respectively; P = .01). Local infection occurred in three participants who underwent RFA (two of whom had undergone partial irradiation of the breast). None of the participants in the control group developed local infection. No participants had recurrence or the need for a second surgery during the study period. Conclusion This preliminary study showed that radiofrequency ablation was effective for local tumor control and that tumor-free margins were obtained more often with radiofrequency ablation than with lumpectomy. Surgical excision after radiofrequency ablation was infrequently associated with local infection. © RSNA, 2018 Online supplemental material is available for this article.