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Introduction: There is no standard treatment after resection of colorectal liver metastases and the role of systemic therapy remains controversial. To avoid over- or undertreatment, proper risk stratification with regard to postoperative treatment strategy is highly needed. We recently demonstrated the prognostic relevance of EMT-related (epithelial-mesenchymal transition) genes in stage II/III CRC. As EMT is a major step in CRC progression, we now aimed to analyse the prognostic relevance of EMT-related genes in stage IV CRC using the study cohort of the FIRE-3 trial, an open-label multi-centre randomised controlled phase III trial of patients with metastatic CRC. Methods: Overall and progression free survival were considered as endpoints (n = 350). To investigate the prognostic relevance of EMT-related genes on either endpoint, we compared predictive performance of different models using clinical data only to models using gene data in addition to clinical data, expecting better predictive performance if EMT-related genes have prognostic value. In addition to baseline models (Kaplan Meier (KM), (regularised) Cox), Random Survival Forest (RSF), and gradient boosted trees (GBT) were fit to the data. Repeated, nested five-fold cross-validation was used for hyperparameter optimisation and performance evaluation. Predictive performance was measured by the integrated Brier score (IBS). Results: The baseline KM model showed the best performance (OS: 0.250, PFS: 0.251). None of the other models were able to outperform the KM when using clinical data only according to the IBS scores (OS: 0.253 (Cox), 0.256 (RSF), 0.284 (GBT); PFS: 0.254 (Cox), 0.256 (RSF), 0.276 (GBT)). When adding gene data, performance of GBT improved slightly (OS: 0.262 vs. 0.284; PFS: 0.268 vs. 0.276), however, none of the models performed better than the KM baseline. Conclusion: Overall, the results suggest that the prognostic relevance of EMT-related genes may be stage-dependent and that EMT-related genes have no prognostic relevance in stage IV CRC.

Background Textbook outcome (TO) is a multidimensional measure reflecting the ideal outcome after surgery. As a benchmarking tool, it provides an objective overview of quality of care. Uniform definitions of TO in hepato-pancreato-biliary (HPB) surgery are missing. This study aimed to provide a definition of TO in HPB surgery and identify obstacles and predictors for achieving it. Methods A systematic literature search was conducted using PubMed, Embase, and Cochrane Database according to PRISMA guidelines. Studies published between 1993 and 2021 were retrieved. After selection, two independent reviewers extracted descriptive statistics and derived summary estimates of the occurrence of TO criteria and obstacles for achieving TO using co-occurrence maps. Results Overall, 30 studies were included. TO rates ranged between 16–69 per cent. Commonly chosen co-occurring criteria to define TO included ‘no prolonged length of stay (LOS)’, ‘no complications’, ‘no readmission’, and ‘no deaths’. Major obstacles for achieving TO in HPB surgery were prolonged LOS, complications, and readmission. On multivariable analysis, TO predicted better overall and disease-free survival in patients with cancer. Achievement of TO was more likely in dedicated centres and associated with procedural and structural indicators, including high case-mix index and surgical volume. Conclusion TO is a useful quality measure to benchmark surgical outcome. Future definitions of TO in HPB surgery should include ‘no prolonged LOS’, ‘no complications’, ‘no readmission’, and ‘no deaths’.

Hepatic ischemia-reperfusion injury (IRI) represents a major challenge during liver surgery, liver preservation for transplantation, and can cause hemorrhagic shock with severe hypoxemia and trauma. The reduction of blood supply with a concomitant deficit in oxygen delivery initiates various molecular mechanisms involving the innate and adaptive immune response, alterations in gene transcription, induction of cell death programs, and changes in metabolic state and vascular function. Hepatic IRI is a major cause of morbidity and mortality, and is associated with an increased risk for tumor growth and recurrence after oncologic surgery for primary and secondary hepatobiliary malignancies. Therapeutic strategies to prevent or treat hepatic IRI have been investigated in animal models but, for the most part, have failed to provide a protective effect in a clinical setting. This review focuses on the molecular mechanisms underlying hepatic IRI and regeneration, as well as its clinical implications. A better understanding of this complex and highly dynamic process may allow for the development of innovative therapeutic approaches and optimize patient outcomes.

In cancer patients, surgical removal of the primary tumor is one of the major steps within a multimodal therapy concept toward eliminating the disease and limiting further progression. In this respect, surgical trauma can have potent effects on the patient's immune system. Intraoperative blood loss associated with major surgical trauma leads to reduced blood flow, regional hypoxia, metabolic, and microenvironmental alterations stimulating an inflammatory response characterized by the release of pro-inflammatory cytokines (i.e., TNF-α, IL-6) and acute-phase proteins. The inflammatory state is accompanied by and intertwined with a counter-regulatory anti-inflammatory response reflected in the rise of anti-inflammatory cytokines (i.e., transforming growth factor-β) and prostaglandins (i.e., prostaglandin E2) which can lead to a depression of cell-mediated immunity and systemic immunosuppression. This results in a highly vulnerable state with concurrent expression of pro- and anti-inflammatory cytokines alternately predominating. The immunosuppressive state is characterized by a reduced antigen-presentation capacity of macrophages, alterations in lymphocyte proliferation, and activation as well as a shift of the Th1/Th2 (T helper cells 1 and 2) balance toward Th2 and a decrease in natural killer cell activity. The severity of the immunosuppression thereby correlates with the extent and the duration of the surgical procedure. Growing evidence suggests that the immunosuppressive state following hemorrhage and surgical trauma might not only be a risk factor for postoperative complications but also facilitate tumor proliferation, metastatic growth, and recurrence. This article provides an overview of the cascade of events and underlying mechanisms resulting in immunosuppression and describes the impact of hemorrhage and major surgical trauma on tumor growth and recurrence. Attempts to control for perioperative inflammation thereby reducing the adverse effects of postoperative immunosuppression could have positive effects on tumor growth, metastasis formation, and recurrence.

Metastasis is the major cause of death in patients with colorectal carcinoma (CRC). The most common sites of metastasis are the liver and the peritoneum. Peritoneal carcinomatosis is often considered the end stage of the disease after the tumor has spread to the liver. However, almost half of CRC patients with peritoneal carcinomatosis do not present with liver metastasis. This brings up the question of whether peritoneal spread can still be considered as the end stage of a metastasized CRC or whether it should just be interpreted as a site of metastasis alternative to the liver. This review tries to discuss this question and summarize the current status of literature on potential characteristics in tumor biology in the primary tumor, i.e., factors (transcription factors and direct and indirect E-cadherin repressors) and pathways (WNT, TGF-β, and RAS) modulating EMT, regulation of EMT on a posttranscriptional and posttranslational level (miRNAs), and angiogenesis. In addition to tumor-specific characteristics, factors in the tumor microenvironment, immunological markers, ways of transport of tumor cells, and adhesion molecules appear to differ between hematogenous and peritoneal spread. Factors such as integrins and exosomal integrins, cancer stem cell phenotype, and miRNA expression appear to contribute in determining the metastatic route. We went through each step of the metastasis process comparing hematogenous to peritoneal spread. We identified differences with respect to organotropism, epithelial-mesenchymal transition, angiogenesis and inflammation, and tumor microenvironment which will be further elucidated in this review. A better understanding of the underlying mechanisms and contributing factors of metastasis development in CRC has huge relevance as it is the foundation to help find specific targets for treatment of CRC.