Robotic Distal Pancreatectomy: A Novel Standard of Care? Benchmark Values for Surgical Outcomes From 16 International Expert Centers.

BACKGROUND AND OBJECTIVE: Robotic distal pancreatectomy (DP) is an emerging attractive approach, but its role compared with laparoscopic or open surgery remains unclear. Benchmark values are novel and objective tools for such comparisons. The aim of this study was to identify benchmark cutoffs for many outcome parameters for DP with or without splenectomy beyond the learning curve. METHODS: This study analyzed outcomes from international expert centers from patients undergoing robotic DP for malignant or benign lesions. After excluding the first 10 cases in each center to reduce the effect of the learning curve, consecutive patients were included from the start of robotic DP up to June 2020. Benchmark patients had no significant comorbidities. Benchmark cutoff values were derived from the 75th or the 25th percentile of the median values of all benchmark centers. Benchmark values were compared with a laparoscopic control group from 4 high-volume centers and published open DP landmark series. RESULTS: Sixteen centers contributed 755 cases, whereof 345 benchmark patients (46%) were included the analysis. Benchmark cutoffs included: operation time ≤300 minutes, conversion rate ≤3%, clinically relevant postoperative pancreatic fistula ≤32%, 3 months major complication rate ≤26.7%, and lymph node retrieval ≥9. The comprehensive complication index at 3 months was ≤8.7 without deterioration thereafter. Compared with robotic DP, laparoscopy had significantly higher conversion rates (5×) and overall complications, while open DP was associated with more blood loss and longer hospital stay. CONCLUSION: This first benchmark study demonstrates that robotic DP provides superior postoperative outcomes compared with laparoscopic and open DP. Robotic DP may be expected to become the approach of choice in minimally invasive DP.

[Robotics in Liver Surgery - Tips and Tricks]. / Robotik in der Leberchirurgie ­ Tipps und Tricks.

Since minimally invasive liver surgery has proven benefits over open surgery, this technique should also be implemented more broadly in Germany. With the dramatic development in minimally invasive and robotic liver surgery, this approach has been established in recent years. Most recent analyses suggest lower complication rates, blood loss and hospital stay compared to open and laparoscopic liver surgery. In contrast to laparoscopic surgery, the technical setting of robotic liver surgery is widely independent of the type of resection. The laparoscopic and robotic technologies should be considered to be equal at the moment, although most recent analyses even suggest additional advantages of robotic over laparoscopic liver surgery. Moreover, robotics has a greater potential for technical refinements, including the inclusion of artificial intelligence and machine learning. Most steps can be transferred from open and laparoscopic liver surgery, but a dissection device such as the CUSA has not yet been developed. Consequently, different techniques have been reported for parenchymal transsection. Due to the special technical features of robotic surgery, intensive training programs should be used prior to the establishment of a robotic liver surgery program.

Impact of enhanced recovery protocols after pancreatoduodenectomy: meta-analysis.

BACKGROUND: This individual-patient data meta-analysis investigated the effects of enhanced recovery after surgery (ERAS) protocols compared with conventional care on postoperative outcomes in patients undergoing pancreatoduodenectomy. METHODS: The Cochrane Library, MEDLINE, Embase, Scopus, and Web of Science were searched systematically for articles reporting outcomes of ERAS after pancreatoduodenectomy published up to August 2020. Comparative studies were included. Main outcomes were postoperative functional recovery elements, postoperative morbidity, duration of hospital stay, and readmission. RESULTS: Individual-patient data were obtained from 17 of 31 eligible studies comprising 3108 patients. Time to liquid (mean difference (MD) -3.23 (95 per cent c.i. -4.62 to -1.85) days; P < 0.001) and solid (-3.84 (-5.09 to -2.60) days; P < 0.001) intake, time to passage of first stool (MD -1.38 (-1.82 to -0.94) days; P < 0.001) and time to removal of the nasogastric tube (3.03 (-4.87 to -1.18) days; P = 0.001) were reduced with ERAS. ERAS was associated with lower overall morbidity (risk difference (RD) -0.04, 95 per cent c.i. -0.08 to -0.01; P = 0.015), less delayed gastric emptying (RD -0.11, -0.22 to -0.01; P = 0.039) and a shorter duration of hospital stay (MD -2.33 (-2.98 to -1.69) days; P < 0.001) without a higher readmission rate. CONCLUSION: ERAS improved postoperative outcome after pancreatoduodenectomy. Implementation should be encouraged.

Enhanced recovery protocols consist of interdisciplinary interventions aimed at standardizing care and reducing the impact of surgical stress. They often include a short period of preoperative fasting during the night before surgery, early removal of lines and surgical drains, early food intake and mobilization out of bed on the day of surgery. This study gives a summary of reports assessing such care protocols in patients undergoing pancreatic head surgery, and assesses the impact of these protocols on functional recovery in an analysis of individual-patient data. The study revealed the true benefits of enhanced recovery protocols, including shorter time to food intake, earlier bowel activity, fewer complications after surgery, and a shorter hospital stay compared with conventional care.

Prehabilitation in patients undergoing colorectal surgery fails to confer reduction in overall morbidity: results of a single-center, blinded, randomized controlled trial.

BACKGROUND: Currently, there are solely weak recommendations in the enhanced recovery after surgery (ERAS) protocol regarding the role of preoperative physical activity and prehabilitation in patients undergoing colorectal surgery. Studies in heterogenous groups showed contradictory results regarding the impact of prehabilitation on the reduction of postoperative complications. The aim of this study was to assess the impact of prehabilitation on postoperative complications in patients undergoing colorectal surgery within an ERAS protocol. METHODS: Between July 2016 and June 2019, a single-center, blinded, randomized controlled trial designed to test whether physiotherapeutic prehabilitation vs. normal physical activities prior to colorectal surgery may decrease morbidity within a stringent ERAS protocol was carried out. The primary endpoint was postoperative complications assessed by Comprehensive Complications Index (CCI®). Primary and secondary endpoints for both groups were analyzed and compared. RESULTS: A total of 107 patients (54 in the prehabilitation enhanced recovery after colorectal surgery [pERACS] group and 53 in the control group) were included in the study and randomized. Dropout rate was 4.5% (n = 5). Baseline characteristics were comparable between the pERACS and control groups. The percentage of colorectal adenocarcinoma was low in both groups (pERACS 32% vs. control 23%, p = 0.384). Almost all patients underwent minimally invasive surgery in both groups (96% vs. 98%, p = 1.000). There was no between-group difference in the primary outcome, as the mean CCI at 30-day postoperative in the pERACS group was 18 (SD 0-43) compared to 15 (SD 0-49) in the control group (p = 0.059). Secondary outcome as complications assessed according to Clavien-Dindo, length of hospital stay, reoperation rate, and mortality showed no difference between both groups. CONCLUSIONS: Routine physiotherapeutic prehabilitation has no additional benefit for patients undergoing colorectal surgery within an ERAS protocol. TRIAL REGISTRATION: ClinicalTrial.gov: ID: NCT02746731; Institution Ethical Board Approval: KEK-ZH Nr. 2016-00,229.

Pancreatic fistulas following distal pancreatectomy are unrelated to the texture quality of the pancreas.

PURPOSE: The relevance of pancreatic texture for pancreatic fistula (POPF) formation after distal pancreatectomy (DP) remains ill defined. Recent POPF definition adjustments and common subjective pancreatic texture assessment are further drawbacks in the investigation of pancreatic texture as a factor for POPF development after DP. METHODS: The predictive value of pancreatic texture by histologic assessment was investigated for POPF formation after DP, respecting the updated 2016 fistula definition. Histologic evaluation at the resection margin included amount of steatosis, degree of fibrosis, and pancreatic duct size. RESULTS: A total of 102 patients who underwent DP were included. Thirty-six patients developed POPF. There was no difference in histologic variables in patients with and without POPF. In the univariate analysis, none of the three histologic features showed significant correlation with POPF formation. The ROC (receiver operating characteristic) curve demonstrated poor utility for the grade of steatosis 0.481 ± 0.058 (p = 0.75) and grade of fibrosis 0.466 ± 0.058 (p = 0.57) as predictive factors for POPF formation. CONCLUSION: Results indicate that pancreatic texture does not predict POPF formation following DP. This is particularly relevant in the context of the increasing use of robotic and laparoscopic approaches for DPs with limited clinical pancreatic texture assessment by palpation.

Association of a prehabilitation program with anxiety and depression before colorectal surgery: a post hoc analysis of the pERACS randomized controlled trial.

PURPOSE: Hospital-associated anxiety and depression are major preoperative stressors and common in colorectal cancer surgery and major abdominal surgery. The prehabilitation Enhanced Recovery After Colorectal Surgery (pERACS) study is a single-center, single-blinded randomized controlled trial (RCT) evaluating the effect of a structured prehabilitation program. We evaluate within this RCT the association of a prehabilitation program with anxiety and depression before colorectal surgery. METHODS: Treatment allocation randomized and single-blinded. Regardless of group allocation, patients were treated according to our institutional Enhanced Recovery After Surgery (ERAS) protocol. Inclusion criteria consisted of adult patients suffering from colorectal disease requiring surgical treatment and who were treated according to the ERAS protocol. Anxiety and depression scores were assessed at baseline and at admission according to the Hospital Anxiety and Depression Scale (HADS), with its subcomponents for depression (HADS-D) and for anxiety (HADS-A). RESULTS: A total of 23 patients randomized to prehabilitation (mean age: 64.8±11.5 years) and 25 patients randomized to the control group (64.0±11.9 years) were included. There was no statistically significant difference in HADS-Anxiety improvement (Prehabilitation: -1.7±2.8 points vs. control: -0.4±3.4 points, p=0.132). Similarly, the difference in HADS-Depression improvement among the prehabilitation (1.0±2.4 points) and control (-0.3 ± 4.0 points) groups (p = 0.543) was non-significant. Clinically meaningful improvement in anxiety (60.9%/40.0%, p=0.149) and depression (34.8%/20.0%, p=0.250) was similar among the groups. CONCLUSION: In a post hoc analysis of a randomized trial, prehabilitation had no effect on preoperative reduction of anxiety and depression measures. TRIAL REGISTRATION NUMBER: Clinicaltrials.gov NCT02746731. Date of registration: April 21, 2016.

Current trends in vena cava reconstructive techniques with major liver resection: a systematic review.

PURPOSE: Historically, invasion of the inferior vena cava (IVC) represented advanced and often unresectable hepatic disease. With surgical and anesthetic innovations, IVC resection and reconstruction have become feasible in selected patients. This review assesses technical variations in reconstructive techniques and post-operative management. METHODS: A comprehensive literature search was performed according to PRISMA. Inclusion criteria were (i) peer-reviewed articles in English; (ii) at least three cases; (iii) hepatic IVC resection and reconstruction (January 2015-March 2020). Primary outcomes were reconstructive technique, anti-thrombotic regimen, post-operative IVC patency, and infection. Secondary outcomes included post-operative complications and malignant disease survival. RESULTS: Fourteen articles were included allowing for investigation of 351 individual patients. Analysis demonstrated significant heterogeneity in surgical reconstructive technique, anti-thrombotic management, and post-operative monitoring of patency. There was increased utilization of ex vivo approaches and decreased use of venovenous bypass compared with previously published reviews. CONCLUSION: This review of literature published between 2015 and 2020 reveals persistent heterogeneity of hepatic IVC reconstructive techniques and peri-operative management. Increased utilization of ex vivo approaches and decreased use of venovenous bypass point towards improved operative techniques, peri-operative management, and anesthesia. In order to gain evidence for consensus on management, a registry would be beneficial.

Perioperative omega-3 fatty acids fail to confer protection in liver surgery: Results of a multicentric, double-blind, randomized controlled trial.

BACKGROUND & AIMS: In a variety of animal models, omega-3 polyunsaturated fatty acids (Ω3-FAs) conferred strong protective effects, alleviating hepatic ischemia/reperfusion injury and steatosis, as well as enhancing regeneration after major tissue loss. Given these benefits along with its safety profile, we hypothesized that perioperative administration of Ω3-FAs in patients undergoing liver surgery may ameliorate the postoperative course. The aim of this study was to investigate the perioperative use of Ω3-FAs to reduce postoperative complications after liver surgery. METHODS: Between July 2013 and July 2018, we carried out a multicentric, double-blind, randomized, placebo-controlled trial designed to test whether 2 single intravenous infusions of Omegaven® (Ω3-FAs) vs. placebo may decrease morbidity. The primary endpoints were postoperative complications by severity (Clavien-Dindo classification) integrated within the comprehensive complication index (CCI). RESULTS: A total of 261 patients (132 in the Omegaven and 129 in the placebo groups) from 3 centers were included in the trial. Most cases (87%, n = 227) underwent open liver surgery and 56% (n = 105) were major resections (≥3 segments). In an intention-to-treat analysis including the dropout cases, the mortality rate was 4% and 2% in the Omegaven and placebo groups (odds ratio0.40;95% CI 0.04-2.51; p = 0.447), respectively. Any complications and major complications (Clavien-Dindo ≥ 3b) occurred in 46% vs. 43% (p = 0.709) and 12% vs. 10% (p = 0.69) in the Omegaven and placebo groups, respectively. The mean CCI was 17 (±23) vs.14 (±20) (p = 0.417). An analysis excluding the dropouts provided similar results. CONCLUSIONS: The routine perioperative use of 2 single doses of intravenous Ω3-FAs (100 ml Omegaven) cannot be recommended in patients undergoing liver surgery (Grade A recommendation). LAY SUMMARY: Despite strong evidence of omega-3 fatty acids having liver-directed, anti-inflammatory and pro-regenerative action in various rodent models, 2 single omega-3 fatty acid infusions given to patients before and during liver surgery failed to reduce complications. Because single omega-3 fatty acid infusions failed to confer liver protection in this trial, they cannot currently be recommended. TRIAL REGISTRATION: ClinicalTrial.gov: ID: NCT01884948; Institution Ethical Board Approval: KEK-ZH-Nr. 2010-0038; Swissmedic Notification: 2012DR3215.

Exercise Improves Outcomes of Surgery on Fatty Liver in Mice: A Novel Effect Mediated by the AMPK Pathway.

OBJECTIVE: To investigate whether exercise improves outcomes of surgery on fatty liver, and whether pharmacological approaches can substitute exercising programs. SUMMARY OF BACKGROUND DATA: Steatosis is the hepatic manifestation of the metabolic syndrome, and decreases the liver's ability to handle inflammatory stress or to regenerate after tissue loss. Exercise activates adenosine monophosphate-activated kinase (AMPK) and mitigates steatosis; however, its impact on ischemia-reperfusion injury and regeneration is unknown. METHODS: We used a mouse model of simple, diet-induced steatosis and assessed the impact of exercise on metabolic parameters, ischemia-reperfusion injury and regeneration after hepatectomy. The same parameters were evaluated after treatment of mice with the AMPK activator 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR). Mice on a control diet served as age-matched controls. RESULTS: A 4-week-exercising program reversed steatosis, lowered insulin levels, and improved glucose tolerance. Exercise markedly enhanced the ischemic tolerance and the regenerative capacity of fatty liver. Replacing exercise with AICAR was sufficient to replicate the above benefits. Both exercise and AICAR improved survival after extended hepatectomy in mice challenged with a Western diet, indicating protection from resection-induced liver failure. CONCLUSIONS: Exercise efficiently counteracts the metabolic, ischemic, and regenerative deficits of fatty liver. AICAR acts as an exercise mimetic in settings of fatty liver disease, an important finding given the compliance issues associated with exercise. Exercising, or its substitution through AICAR, may provide a feasible strategy to negate the hepatic consequences of energy-rich diet, and has the potential to extend the application of liver surgery if confirmed in humans.

Allocation of liver grafts worldwide - Is there a best system?

BACKGROUND & AIMS: An optimal allocation system for scarce resources should simultaneously ensure maximal utility, but also equity. The most frequent principles for allocation policies in liver transplantation are therefore criteria that rely on pre-transplant survival (sickest first policy), post-transplant survival (utility), or on their combination (benefit). However, large differences exist between centers and countries for ethical and legislative reasons. The aim of this study was to report the current worldwide practice of liver graft allocation and discuss respective advantages and disadvantages. METHODS: Countries around the world that perform 95 or more deceased donor liver transplantations per year were analyzed for donation and allocation policies, as well as recipient characteristics. RESULTS: Most countries use the model for end-stage liver disease (MELD) score, or variations of it, for organ allocation, while some countries opt for center-based allocation systems based on their specific requirements, and some countries combine both a MELD and center-based approach. Both the MELD and center-specific allocation systems have inherent limitations. For example, most countries or allocation systems address the limitations of the MELD system by adding extra points to recipient's laboratory scores based on clinical information. It is also clear from this study that cancer, as an indication for liver transplantation, requires special attention. CONCLUSION: The sickest first policy is the most reasonable basis for the allocation of liver grafts. While MELD is currently the standard for this model, many adjustments were implemented in most countries. A future globally applicable strategy should combine donor and recipient factors, predicting probability of death on the waiting list, post-transplant survival and morbidity, and perhaps costs. LAY SUMMARY: An optimal allocation system for scarce resources should simultaneously ensure maximal utility, but also equity. While the model for end-stage liver disease is currently the standard for this model, many adjustments were implemented in most countries. A future globally applicable strategy should combine donor and recipient factors predicting probability of death on the waiting list, post-transplant survival and morbidity, and perhaps costs.

Defining Benchmark Outcomes for ALPPS.

OBJECTIVE: The aim of this study was to use the concept of benchmarking to establish robust and standardized outcome references after the procedure ALPPS (Associating Liver Partition and Portal Vein Ligation for Staged hepatectomy). BACKGROUND AND AIMS: The recently developed ALPPS procedure, aiming at removing primarily unresectable liver tumors, has been criticized for safety issues with high variations in the reported morbidity/mortality rates depending on patient, disease, technical characteristics, and center experience. No reference values for relevant outcome parameters are available. METHODS: Among 1036 patients registered in the international ALPPS registry, 120 (12%) were benchmark cases fulfilling 4 criteria: patients ≤67 years of age, with colorectal metastases, without simultaneous abdominal procedures, and centers having performed ≥30 cases. Benchmark values, defined as the 75th percentile of the median outcome parameters of the centers, were established for 10 clinically relevant domains. RESULTS: The benchmark values were completion of stage 2: ≥96%, postoperative liver failure (ISGLS-criteria) after stage 2: ≤5%, ICU stay after ALPPS stages 1 and 2: ≤1 and ≤2 days, respectively, interstage interval: ≤16 days, hospital stay after ALPPS stage 2: ≤10 days, rates of overall morbidity in combining both stage 1 and 2: ≤65% and for major complications (grade ≥3a): ≤38%, 90-day comprehensive complication index was ≤22, the 30-, 90-day, and 6-month mortality was ≤4%, ≤5%, and 6%, respectively, the overall 1-year, recurrence-free, liver-tumor-free, and extrahepatic disease-free survival was ≥86%, ≥50%, ≥57%, and ≥65%, respectively. CONCLUSIONS: This benchmark analysis sets key reference values for ALPPS, indicating similar outcome as other types of major hepatectomies. Benchmark cutoffs offer valid tools not only for comparisons with other procedures, but also to assess higher risk groups of patients or different indications than colorectal metastases.

Benchmarks in Pancreatic Surgery: A Novel Tool for Unbiased Outcome Comparisons.

OBJECTIVE: To use the concept of benchmarking to establish robust and standardized outcome references after pancreatico-duodenectomy (PD). BACKGROUND: Best achievable results after PD are unknown. Consequently, outcome comparisons among different cohorts, centers or with novel surgical techniques remain speculative. METHODS: This multicenter study analyzes consecutive patients (2012-2015) undergoing PD in 23 international expert centers in pancreas surgery. Outcomes in patients without significant comorbidities and major vascular resection (benchmark cases) were analyzed to establish 20 outcome benchmarks for PD. These benchmarks were tested in a cohort with a poorer preoperative physical status (ASA class ≥3) and a cohort treated by minimally invasive approaches. RESULTS: Two thousand three hundred seventy-five (38%) low-risk cases out of a total of 6186 PDs were analyzed, disclosing low in-hospital mortality (≤1.6%) but high morbidity, with a 73% benchmark morbidity rate cumulated within 6 months following surgery. Benchmark cutoffs for pancreatic fistulas (B-C), severe complications (≥ grade 3), and failure-to-rescue rate were 19%, 30%, and 9%, respectively. The ASA ≥3 cohort showed comparable morbidity but a higher in hospital-mortality (3% vs 1.6%) and failure-to-rescue rate (16% vs 9%) than the benchmarks. The proportion of benchmark cases performed varied greatly across centers and continents for both open (9%-93%) and minimally invasive (11%-62%) PD. Centers operating mostly on complex PD cases disclosed better results than those with a majority of low-risk cases. CONCLUSION: The proposed outcome benchmarks for PD, established in a large-scale international patient cohort and tested in 2 different cohorts, may allow for meaningful comparisons between different patient cohorts, centers, countries, and surgical techniques.

Novel Benefits of Remote Ischemic Preconditioning Through VEGF-dependent Protection From Resection-induced Liver Failure in the Mouse.

OBJECTIVE: To investigate the impact of remote ischemic preconditioning (RIPC) on liver regeneration after major hepatectomy. SUMMARY BACKGROUND DATA: RIPC is a strategy applied at remote sites to mitigate ischemic injury. Unlike other preconditioning approaches, RIPC spares target organs as it acts via systemic VEGF elevations. In the liver, however, VEGF is an important driver of regeneration following resection. Therefore, RIPC may have pro-regenerative effects. METHODS: RIPC was applied to C57BL/6 mice through intermittent clamping of the femoral vessels prior to standard 68%-hepatectomy or extended 86%-hepatectomy, with the latter causing liver failure and impaired survival. Liver regeneration was assessed through weight gain, proliferative markers (Ki67, pH3, mitoses), cell cycle-associated molecules, and survival. The role of the VEGF-ID1-WNT2 signaling axis was assessed through WIF1 (a WNT antagonist) and recombinant WNT2 injected prior to hepatectomy. RESULTS: RIPC did not affect regeneration after 68%-hepatectomy, but improved liver weight gain and hepatocyte mitoses after 86%-hepatectomy. Importantly, RIPC raised survival from 40% to 80% after 86%-hepatectomy, indicating the promotion of functional recovery. Mechanistically, the RIPC-induced elevations in VEGF were accompanied by increases in the endothelial transcription factor Id1, its target WNT2, and its hepatocellular effector ß-catenin. WIF1 injection prior to 86%-hepatectomy abrogated the RIPC benefits, while recombinant WNT2 had pro-regenerative effects akin to RIPC. CONCLUSION: RIPC improves the regenerative capacity of marginal liver remnants in a VEGF-dependent way. If confirmed in patients, RIPC may become the preconditioning strategy of choice in the setting of extended liver resections.

PTEN Down-Regulation Promotes ß-Oxidation to Fuel Hypertrophic Liver Growth After Hepatectomy in Mice.

In regenerating liver, hepatocytes accumulate lipids before the major wave of parenchymal growth. This transient, regeneration-associated steatosis (TRAS) is required for liver recovery, but its purpose is unclear. The tumor suppressor phosphatase and tensin homolog (PTEN) is a key inhibitor of the protein kinase B/mammalian target of rapamycin axis that regulates growth and metabolic adaptations after hepatectomy. In quiescent liver, PTEN causes pathological steatosis when lost, whereas its role in regenerating liver remains unknown. Here, we show that PTEN down-regulation promotes liver growth in a TRAS-dependent way. In wild-type mice, PTEN reduction occurred after TRAS formation, persisted during its disappearance, and correlated with up-regulated ß-oxidation at the expense of lipogenesis. Pharmacological modulation revealed an association of PTEN with TRAS turnover and hypertrophic liver growth. In liver-specific Pten-/- mice shortly after induction of knockout, hypertrophic regeneration was accelerated and led to hepatomegaly. The resulting surplus liver mass was functional, as demonstrated by raised survival in a lethal model of resection-induced liver failure. Indirect calorimetry revealed lipid oxidation as the primary energy source early after hepatectomy. The shift from glucose to lipid usage was pronounced in Pten-/- mice and correlated with the disappearance of TRAS. Partial inhibition of ß-oxidation led to persisting TRAS in Pten-/- mice and abrogated hypertrophic liver growth. PTEN down-regulation may promote ß-oxidation through ß-catenin, whereas hypertrophy was dependent on mammalian target of rapamycin complex 1. CONCLUSION: PTEN down-regulation after hepatectomy promotes the burning of TRAS-derived lipids to fuel hypertrophic liver regeneration. Therefore, the anabolic function of PTEN deficiency in resting liver is transformed into catabolic activities upon tissue loss. These findings portray PTEN as a node coordinating liver growth with its energy demands and emphasize the need of lipids for regeneration. (Hepatology 2017;66:908-921).

Systematic review and meta-analysis of postoperative pancreatic fistula rates using the updated 2016 International Study Group Pancreatic Fistula definition in patients undergoing pancreatic resection with soft and hard pancreatic texture.

BACKGROUND: In 2016, the International Study Group of Pancreatic Fistula (ISGPS) proposed an updated definition for postoperative pancreatic fistula (POPF). Pancreas texture (PT) is an established risk factor of POPF. The definition of soft vs. hard texture, however, remains elusive. METHODS: A systematic search was performed to identify PT definitions and a meta-analysis linking POPF to PT using the updated ISGPS definition. RESULTS: 122 studies including 22 376 patients were identified. Definition criteria for PT varied among studies and most classified PT in hard and soft based on intraoperative subjective assessment. The total POPF rate (pooled grades B and C) after pancreatoduodenectomy was 14.5% (n = 10 395) and 15.5% (n = 3767) after distal pancreatectomy. In pancreatoduodenectomy, POPF rate was higher in soft compared to hard pancreas (RR, 4.4, 3.3 to 6.1; p < 0.001; n = 6393), where PT grouped as soft and hard. No data were available for intermediate PT. CONCLUSION: The reported POPF rates may be used in planning future prospective studies. A widely accepted definition of PT is lacking and a correlation with the risk of POPF is based on subjective evaluation, which is still acceptable. Classification of PT into 2-groups is more reasonable than classification into 3-groups.

The Allosteric Hemoglobin Effector ITPP Inhibits Metastatic Colon Cancer in Mice.

OBJECTIVE: To test the effects of enhanced intracellular oxygen contents on the metastatic potential of colon cancer. BACKGROUND: Colorectal cancer is the commonest gastrointestinal carcinoma. Distant metastases occur in half of patients and are responsible for most cancer-related deaths. Tumor hypoxia is central to the pathogenesis of metastases. Myo-Inositoltrispyrophosphate (ITPP), a nontoxic, antihypoxic compound, has recently shown significant benefits in experimental cancer, particularly when combined with standard chemotherapy. Whether ITPP protects from distant metastases in primary colon cancer is unknown. METHODS: ITPP alone or combined with FOLFOX was tested in a mouse model with cecal implantation of green fluorescent protein-labeled syngeneic colorectal cancer cells. Tumor development was monitored through longitudinal magnetic resonance imaging-based morphometric analysis and survival. Established serum markers of tumor spread were measured serially and circulating tumor cells were detected via fluorescence measurements. RESULTS: ITPP significantly reduced the occurrence of metastases as well as other indicators of tumor aggressiveness. Less circulating tumor cells along with reduction in malignant serum markers (osteopontin, Cxcl12) were noted. The ITPP benefits also affected the primary cancer site. Importantly, animals treated with ITPP had a significant survival benefit compared with respective controls, while a combination of FOLFOX with ITPP conferred the maximum benefits, including dramatic improvements in survival (mean 86 vs 188 d). CONCLUSIONS: Restoring oxygen in metastatic colon cancer through ITPP inhibits tumor spread and markedly improves animal survival; an effect that is enhanced through the application of subsequent chemotherapy. These promising novel findings call for a clinical trial on ITPP in patients with colorectal cancer, which is under way.

Omega-3 Fatty Acids Protect Fatty and Lean Mouse Livers After Major Hepatectomy.

OBJECTIVE: The aim of this study was to assess the effect of Ω3 fatty acids (Ω3FA) on fatty and lean liver in hepatic surgery. BACKGROUND: The global spread of energy-dense diets has led to an endemic rise in fatty liver disease and obesity. Besides metabolic pathologies, steatosis enhances hepatic sensitivity to ischemia reperfusion (I/R) and impedes liver regeneration (LR). Steatosis limits the application of liver surgery, still the main curative option for liver cancer. Ω3FA are known to reverse steatosis, but how these lipids affect key factors defining surgical outcomes-that is, I/R, LR, and liver malignancy-is less clear. METHODS: We established a standardized mouse model of high fat diet (HFD)-induced steatosis followed by Ω3FA treatment and the subsequent assessment of Ω3FA effects on I/R, LR, and liver malignancy (n = 5/group), the latter through a syngeneic metastasis approach. Fatty liver outcomes were compared with lean liver to assess steatosis-independent effects. Nonparametric statistics were applied. RESULTS: Ω3FA reversed HFD-induced steatosis and markedly protected against I/R, improved LR, and prolonged survival of tumor-laden mice. Remarkably, these beneficial effects were also observed in lean liver, albeit at a smaller scale. Notably, mice with metastases in fatty versus lean livers were associated with improved survival. CONCLUSIONS: Ω3FA revealed multiple beneficial effects in fatty and lean livers in mice. The improvements in I/R injury, regenerative capacity, and oncological outcomes await confirmatory studies in humans.

Constitutive androstane receptor (Car)-driven regeneration protects liver from failure following tissue loss.

BACKGROUND & AIMS: Liver can recover following resection. If tissue loss is too excessive, however, liver failure will develop as is known from the small-for-size-syndrome (SFSS). The molecular processes underlying liver failure are ill-understood. Here, we explored the role and the clinical potential of Nr1i3 (constitutive androstane receptor, Car) in liver failure following hepatectomy. METHODS: Activators of Car, various hepatectomies, Car(-/-) mice, humanized CAR mice, human tissue and ex vivo liver slice cultures were used to study Car in the SFSS. Pathways downstream of Car were investigated by in vivo siRNA knockdown. RESULTS: Excessive tissue loss causing liver failure is associated with deficient induction of Car. Reactivation of Car by an agonist normalizes all features associated with experimental SFSS. The beneficial effects of Car activation are relayed through Foxm1, an essential promoter of the hepatocyte cell cycle. Deficiency in the CAR-FOXM1 axis likewise is evident in human SFSS. Activation of human CAR mitigates SFSS in humanized CAR mice and improves the culture of human liver slices. CONCLUSIONS: Impaired hepatic Car-Foxm1 signaling provides a first molecular characterization of liver that fails to recover after tissue loss. Our findings place deficient regeneration as a principal cause behind the SFSS and suggest CAR agonists may bear clinical potential against liver failure. LAY SUMMARY: The unique regenerative capacity of liver has its natural limits. Following tissue loss that is too excessive, such as through extended resection in the clinic, liver failure may develop. This is known as small-for-size-syndrome (SFSS) and represents the most frequent cause of death due to liver surgery. Here we show that deficient induction of the protein Car, a central regulator of liver function and growth, is a cause of liver failure following extended resection; reactivation of Car through pharmacological means is sufficient to prevent or rescue the SFSS.