Enhanced recovery after surgery for liver transplantation: a review of recent literature.

PURPOSE OF REVIEW: This review was created to highlight important articles from the past year related to the evolving field of enhanced recovery after surgery (ERAS) in liver transplantation that are relevant to the transplant anesthesiologist. RECENT FINDINGS: The International Liver Transplantation Society (ILTS) recently completed a landmark project, the ERAS4OLT.org project, which culminated in 80 recommendations for ERAS in liver transplantation. These recommendations encompass management for deceased donor recipients, living donor recipients and living donors. This review highlights selected articles relevant to the perioperative management of deceased donor liver transplant recipients. SUMMARY: Though, there are now published internationally agreed upon recommendations for ERAS topics specific to liver transplantation, there is an obvious need for further investigation into this area to provide high quality evidence to support these recommendations. It is reasonable to utilize these recommendations in ERAS protocols for individual institutions; however, more evidence is needed in several areas to confirm the effects of these protocols on short-term outcomes.

The in-vitro influence of urea concentration on thromboelastrography in patients with and without end stage renal disease.

BACKGROUND: End stage renal disease (ESRD) is associated with platelet dysfunction but also thromboembolic complications. The specific role of increased blood urea nitrogen (BUN) on coagulation is unclear. We aimed to characterize thromboelastography (TEG) parameters from males and females with ESRD and normal kidney function and evaluate if exogenous urea in vitro reproduced those TEG differences. METHODS: We collected blood samples from 20 living kidney donors and 20 kidney recipients. TEG was performed without and with two increasing urea concentrations in vitro. TEG parameters were compared between recipients and donors. RESULTS: Blood from kidney recipients showed baseline increased maximum amplitude (MA) and shortened time to maximum amplitude (TMA) compared to donors. These differences were not confirmed in females. In all patients, BUN was inversely correlated with TMA (r = -0.342; p = 0.031). In males, BUN and creatinine concentrations showed a direct correlation with MA (0.583; p = 0.007) and an inverse correlation with TMA (r = -0.520; p = 0.019). Urea in vitro decreased R-time (p = 0.005) and increased LY30 (p = 0.009) in donors but not recipients. CONCLUSIONS: ESRD is associated with increased MA and decreased TMA on TEG. No change in MA was observed with increasing urea concentrations in vitro. Gender-specific variability in TEG parameters were observed.

Single-Cell Analysis Reveals Transcriptomic Features of Drug-Tolerant Persisters and Stromal Adaptation in a Patient-Derived EGFR-Mutated Lung Adenocarcinoma Xenograft Model.

INTRODUCTION: Targeted therapies require life-long treatment, as drug discontinuation invariably leads to tumor recurrence. Recurrence is mainly driven by minor subpopulations of drug-tolerant persister (DTP) cells that survive the cytotoxic drug effect. In lung cancer, DTP studies have mainly been conducted with cell line models. METHODS: We conducted an in vivo DTP study using a lung adenocarcinoma patient-derived xenograft tumor driven by an EGFR mutation. Daily treatment of tumor-bearing mice for 5 to 6 weeks with the EGFR inhibitor erlotinib markedly shrunk tumors and generated DTPs, which were analyzed by whole exome, bulk population transcriptome, and single-cell RNA sequencing. RESULTS: The DTP tumors maintained the genomic clonal architecture of untreated baseline (BL) tumors but had reduced proliferation. Single-cell RNA sequencing identified a rare (approximately 4%) subpopulation of BL cells (DTP-like) with transcriptomic similarity to DTP cells and intermediate activity of pathways that are up-regulated in DTPs. Furthermore, the predominant transforming growth factor-ß activated cancer-associated fibroblast (CAF) population in BL tumors was replaced by a CAF population enriched for IL6 production. In vitro experiments indicate that these populations interconvert depending on the levels of transforming growth factor-ß versus NF-κB signaling, which is modulated by tyrosine kinase inhibitor presence. The DTPs had signs of increased NF-κB and STAT3 signaling, which may promote their survival. CONCLUSIONS: The DTPs may arise from a specific preexisting subpopulation of cancer cells with partial activation of specific drug resistance pathways. Tyrosine kinase inhibitor treatment induces DTPs revealing greater activation of these pathways while converting the major preexisting CAF population into a new state that may further promote DTP survival.

Viscoelastic Management of Coagulopathy during the Perioperative Period of Liver Transplantation.

Viscoelastic testing (VET) in liver transplantation (LT) has been used since its origin, in combination with standard laboratory testing (SLT). There are only a few, small, randomized controlled trials that demonstrated a reduction in transfusion rates using VET to guide coagulation management. Retrospective analyses contrasting VET to SLT have demonstrated mixed results, with a recent concern for overtreatment and the increase in postoperative thrombotic events. An oversight of many studies evaluating VET in LT is a single protocol that does not address the different phases of surgery, in addition to pre- and postoperative management. Furthermore, the coagulation spectrum of patients entering and exiting the operating room is diverse, as these patients can have varying anatomic and physiologic risk factors for thrombosis. A single transfusion strategy for all is short sighted. VET in combination with SLT creates the opportunity for personalized resuscitation in surgery which can address the many challenges in LT where patients are at a paradoxical risk for both life-threatening bleeding and clotting. With emerging data on the role of rebalanced coagulation in cirrhosis and hypercoagulability following LT, there are numerous potential roles in VET management of LT that have been unaddressed.

Analytical Validation of a Deep Neural Network Algorithm for the Detection of Ovarian Cancer.

PURPOSE: Early detection of ovarian cancer, the deadliest gynecologic cancer, is crucial for reducing mortality. Current noninvasive risk assessment measures include protein biomarkers in combination with other clinical factors, which vary in their accuracy. Machine learning can be applied to optimizing the combination of these features, leading to more accurate assessment of malignancy. However, the low prevalence of the disease can make rigorous validation of these tests challenging and can result in unbalanced performance. METHODS: MIA3G is a deep feedforward neural network for ovarian cancer risk assessment, using seven protein biomarkers along with age and menopausal status as input features. The algorithm was developed on a heterogenous data set of 1,067 serum specimens from women with adnexal masses (prevalence = 31.8%). It was subsequently validated on a cohort almost twice that size (N = 2,000). RESULTS: In the analytical validation data set (prevalence = 4.9%), MIA3G demonstrated a sensitivity of 89.8% and a specificity of 84.02%. The positive predictive value was 22.45%, and the negative predictive value was 99.38%. When stratified by cancer type and stage, MIA3G achieved sensitivities of 94.94% for epithelial ovarian cancer, 76.92% for early-stage cancer, and 98.04% for late-stage cancer. CONCLUSION: The balanced performance of MIA3G leads to a high sensitivity and high specificity, a combination that may be clinically useful for providers in evaluating the appropriate management strategy for their patients. Limitations of this work include the largely retrospective nature of the data set and the unequal, albeit random, assignment of histologic subtypes between the training and validation data sets. Future directions may include the addition of new biomarkers or other modalities to strengthen the performance of the algorithm.

Assessing therapy response in patient-derived xenografts.

Quantifying response to drug treatment in mouse models of human cancer is important for treatment development and assignment, yet remains a challenging task. To be able to translate the results of the experiments more readily, a preferred measure to quantify this response should take into account more of the available experimental data, including both tumor size over time and the variation among replicates. We propose a theoretically grounded measure, KuLGaP, to compute the difference between the treatment and control arms. We test and compare KuLGaP to four widely used response measures using 329 patient-derived xenograft (PDX) models. Our results show that KuLGaP is more selective than currently existing measures, reduces the risk of false-positive calls, and improves translation of the laboratory results to clinical practice. We also show that outcomes of human treatment better align with the results of the KuLGaP measure than other response measures. KuLGaP has the potential to become a measure of choice for quantifying drug treatment in mouse models as it can be easily used via the kulgap.ca website.

Predictors of participant nonadherence in lung cancer screening programs: a systematic review and meta-analysis.

The low nonadherence rates reported by large low-dose computed tomography (LDCT) lung cancer screening trials were not necessarily replicated outside of trial conditions. This systematic review and meta-analysis identified predictors of participant nonadherence to returning for annual LDCT screening. The systematic review protocol was registered at PROSPERO (CRD42019118347). MEDLINE, EMBASE, CINAHL, AgeLine, grey literature sources, and reference lists of included studies were searched until March 1st, 2020. Primary research articles were eligible for inclusion if they screened current or former smokers using LDCT as their primary screening modality and reported on participant demographics or programmatic interventions that predicted nonadherence. Risk of bias assessment was performed at both study and outcome levels. The primary outcome was predictors of nonadherence. The secondary outcomes were relative risks (RR) of second round nonadherence based on identified predictors, which were calculated using random-effects meta-analyses. Across 13 included studies (total n = 15,790; range: 157-3642), the overall rate of nonadherence was 28% (95% CI: 20-37%). Studies identified greater nonadherence in participants younger than 60 or older than 74, with longer travel distances to screening centers, and having a low risk perception of lung cancer. Meta-analyses identified higher nonadherence in community-based compared to academic-based programs, but this did not reach significance (32% versus 27%; p = 0.32). Current smokers were more likely to be nonadherent compared to former smokers (RR 1.23, 95% CI: 1.09-1.40; p < 0.01) while white participants were less likely nonadherent compared to non-white participants (RR 0.69, 95% CI: 0.60-0.81; p < 0.0001). No differences existed between male and female participants (RR 0.99, 95% CI: 0.85-1.15; p = 0.85). Programmatic interventions, including dedicated program coordinators, reminder calls/letters, and mobile LDCT scanners reduced nonadherence in lung cancer screening programs. These interventions should be targeted/tailored toward the subpopulations with the highest nonadherence rates.

EGFR-mutated lung adenocarcinomas from patients who progressed on EGFR-inhibitors show high engraftment rates in xenograft models.

OBJECTIVE: Patient-derived xenografts (PDX) are useful preclinical models to study cancer biology and mechanisms of drug response/resistance, particularly in molecularly targetable tumors. However, PDX engraftment may not be stochastic. We investigated clinical, histological and molecular features associated with PDX engraftment in a large cohort of EGFR-mutated lung adenocarcinoma (LUAD). MATERIAL AND METHODS: Samples were collected by different methods from patients at various disease stages and phases of treatment. PDX engraftment was defined as an ability to passage tumors twice in NOD-SCID mice. Uni- and multivariate logistic regression evaluated factors associated with engraftment. RESULTS: Among 138 EGFR-mutated LUAD implanted into NOD-SCID mice, the overall engraftment rate was only 10% (14/138). However, engraftment was significantly higher in specimens from surgical resections or core-needle biopsies collected from metastatic sites (5/5; 100%) or from patients who had progressed on EGFR-inhibitors (7/10; 70%). Engrafted tumors usually showed poor histological differentiation, a solid morphologic pattern, and presence of either EGFR T790 M and/or TP53 mutations. CONCLUSIONS: Population level analyses of mutant EGFR-PDX show that these models might not fully recapitulate the inter-patient heterogeneity of EGFR-LUAD. However, mutant EGFR-PDXs may be useful to address key clinical questions, notably development of resistance to EGFR-inhibitors and disease progression to distant metastases.

Real-World EQ5D Health Utility Scores for Patients With Metastatic Lung Cancer by Molecular Alteration and Response to Therapy.

INTRODUCTION: Economic analyses of upcoming treatments for lung cancer benefit from real-world health utility scores (HUSs) in an era of targeted therapy. METHODS: A longitudinal cohort study at Princess Margaret Cancer Centre evaluated 1571 EQ5D-3L-derived HUSs in 475 outpatients with metastatic lung cancer across various disease states. Patients with epidermal growth factor receptor (EGFR) (n = 183) and anaplastic lymphoma kinase (ALK) (n = 38) driver alterations were enriched through targeted enrolment; patients with wild-type non-small-cell lung cancer (WT NSCLC) (n = 224) and small-cell lung cancer (SCLC) (n = 30) were sampled randomly. RESULTS: For patients stable on most appropriate treatment, the mean HUSs were 0.81 and 0.82 in patients receiving EGFR and ALK tyrosine kinase inhibitors (TKIs) respectively (with similar HUSs across agents), which were higher than patients with WT NSCLC (0.78; P = .04) and SCLC receiving chemotherapy (0.72; P = .06). In mutation-specific comparisons, disease stability on appropriate therapy resulted in significantly higher mean HUSs (P < .002-.02) than when disease was progressing (mean HUS: EGFR, 0.70; ALK, 0.69; WT NSCLC, 0.66; SCLC, 0.52). When evaluating treatment-related toxicities, significant inverse relationships were observed between HUS and the severity of fatigue and decreased appetite in the EGFR group. There was also a significant inverse relationship between the total number of clinically significant symptoms and HUS, both in patients who were EGFR-mutated and patients with WT NSCLC. CONCLUSIONS: In a North American setting, HUSs generated from patients with metastatic lung cancer are higher in treated, stable patients carrying driver mutations. This is partially explainable by treatment toxicity and patient symptom differences. Such differences in scores should be considered in economic analyses.

Cetuximab Inhibits T790M-Mediated Resistance to Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitor in a Lung Adenocarcinoma Patient-Derived Xenograft Mouse Model.

BACKGROUND: The epidermal growth factor receptor (EGFR) kinase domain T790M (amino acid substitution at position 790 in EGFR from threonine [T] to methionine [M]) mutation in non-small-cell lung cancer (NSCLC) results in resistance to EGFR tyrosine kinase inhibitors (TKIs). We used a patient-derived tumor xenograft (PDX) model containing an EGFR exon 19 deletion/T790M mutation to assess response to the EGFR-directed antibody cetuximab. Changes in the EGFR signaling pathway and ligand expression after treatment were investigated. METHODS: PDX were randomized into control and treatment arms. Pharmacodynamic studies were performed at 2 and 24 hours and at 4 days after a single administration of cetuximab, erlotinib, or dacomitinib. Changes in the EGFR signaling pathway were assessed using Western blot analysis, and baseline mRNA expression of EGFR ligands using microarray analysis. Relative changes after treatment were assessed using quantitative polymerase chain reaction. RESULTS: The xenograft showed a dramatic response to cetuximab. A complete reduction of total EGFR and phosphorylated EGFR occurred after cetuximab treatment. The PDX had increased baseline levels of heparin-binding epidermal growth factor-like growth factor (HB-EGF) compared with other PDX models with or without EGFR mutations. Amphiregulin was significantly reduced 2 hours after treatment with cetuximab. Compared with control mice, cetuximab- and EGFR-TKI-treated mice had significantly reduced HB-EGF gene expression at 2 hours, however, by day 4 the level of HB-EGF expression was higher. The effect of cetuximab compared with EGFR TKI on HB-EGF gene expression levels differed significantly at 2 and 24 hours but not at 4 days. CONCLUSION: We showed a dramatic tumor response with cetuximab in an exon 19 deletion/T790M EGFR mutant lung adenocarcinoma PDX model, which suggests a role for the autocrine feedback loop in the mutant EGFR signaling pathway. Further investigation using cetuximab in NSCLC with T790M mutation is warranted.

Clinical Utility of Patient-Derived Xenografts to Determine Biomarkers of Prognosis and Map Resistance Pathways in EGFR-Mutant Lung Adenocarcinoma.

PURPOSE: Although epidermal growth factor receptor (EGFR) -mutated adenocarcinomas initially have high response rates to EGFR tyrosine kinase inhibitors (TKIs), most patients eventually develop resistance. Patient-derived xenografts (PDXs) are considered preferred preclinical models to study the biology of patient tumors. EGFR-mutant PDX models may be valuable tools to study the biology of these tumors and to elucidate mechanisms of resistance to EGFR-targeted therapies. METHODS: Surgically resected early-stage non-small-cell lung carcinoma (NSCLC) tumors were implanted into nonobese diabetic severe combined immune deficient (NOD-SCID) mice. EGFR TKI treatment was initiated at tumor volumes of 150 µL. Gene expression analysis was performed using a microarray platform. RESULTS: Of 33 lung adenocarcinomas with EGFR activating mutations, only 6 (18%) engrafted and could be propagated beyond passage one. Engraftment was associated with upregulation of genes involved in mitotic checkpoint and cell proliferation. A differentially expressed gene set between engrafting and nonengrafting patients could identify patients harboring EGFR-mutant tumor with significantly different prognoses in The Cancer Genome Atlas Lung Adenocarcinoma datasets. The PDXs included models with variable sensitivity to first- and second-generation EGFR TKIs and the monoclonal antibody cetuximab. All EGFR-mutant NSCLC PDXs studied closely recapitulated their corresponding patient tumor phenotype and clinical course, including response pattern to EGFR TKIs. CONCLUSION: PDX models closely recapitulate primary tumor biology and clinical outcome. They may serve as important laboratory models to investigate mechanisms of resistance to targeted therapies, and for preclinical testing of novel treatment strategies.

Known and putative mechanisms of resistance to EGFR targeted therapies in NSCLC patients with EGFR mutations-a review.

Lung cancer is the leading cause of cancer related deaths in Canada with non-small cell lung cancer (NSCLC) being the predominant form of the disease. Tumor characterization can identify cancer-driving mutations as treatment targets. One of the most successful examples of cancer targeted therapy is inhibition of mutated epidermal growth factor receptor (EGFR), which occurs in ~10-30% of NSCLC patients. While this treatment has benefited many patients with activating EGFR mutations, almost all who initially benefited will eventually acquire resistance. Approximately 50% of cases of acquired resistance (AR) are due to a secondary T790M mutation in exon 20 of the EGFR gene; however, many of the remaining mechanisms of resistance are still unknown. Much work has been done to elucidate the remaining mechanisms of resistance. This review aims to highlight both the mechanisms of resistance that have already been identified in patients and potential novel mechanisms identified in preclinical models which have yet to be validated in the patient settings.

A unique population of bone marrow cells migrates to skeletal muscle via hepatocyte growth factor/c-met axis.

Cells expressing the CD45-associated hematopoietic marker are predominantly present in the mammalian bone marrow (BM), but have recently been shown to also reside in the skeletal muscle and potentially participate in muscle repair. Despite the consistent observations, the specific relationship and potential migration of CD45+ cells in the BM versus CD45+ cells residing in the muscle remain unclear, in addition to any understanding of the factors that may regulate the trafficking of CD45+-derived BM cells to skeletal muscle upon i.v. transplantation. Here, transplantation of BM-derived cells fully replaced the CD45+ fraction of skeletal muscle, but gave rise to progenitor cells with distinct hematopoietic lineage capacity from CD45+ cells residing in the BM. Using transwell migration assays, a subset of BM cells was shown to migrate exclusively to mature skeletal muscle cells and not BM-derived stromal cells. Unlike migration of BM cells to stroma, myofiber induced migration of BM-derived cells was not affected by stromal-derived factor-1 (SDF-1) neutralization or CXCR4-blocking antibody, but could be reduced by addition of c-met-blocking antibody and augmented by hepatocyte growth factor (HGF), the putative ligand for c-met. We suggest that the BM compartment consists of a functionally complex population of CD45+ progenitors that includes a subset of HGF/c-met responsive cells capable of migration to skeletal muscle. This previously unappreciated basis for cellular tracking now aids in defining regulatory networks that distinguish the stem cell niche of the BM versus skeletal muscle microenvironments.