Hemicolectomy versus appendectomy for patients with appendiceal neuroendocrine tumours 1-2 cm in size: a retrospective, Europe-wide, pooled cohort study.

BACKGROUND: Awareness of the potential global overtreatment of patients with appendiceal neuroendocrine tumours (NETs) of 1-2 cm in size by performing oncological resections is increasing, but the rarity of this tumour has impeded clear recommendations to date. We aimed to assess the malignant potential of appendiceal NETs of 1-2 cm in size in patients with or without right-sided hemicolectomy. METHODS: In this retrospective cohort study, we pooled data from 40 hospitals in 15 European countries for patients of any age and Eastern Cooperative Oncology Group performance status with a histopathologically confirmed appendiceal NET of 1-2 cm in size who had a complete resection of the primary tumour between Jan 1, 2000, and Dec 31, 2010. Patients either had an appendectomy only or an appendectomy with oncological right-sided hemicolectomy or ileocecal resection. Predefined primary outcomes were the frequency of distant metastases and tumour-related mortality. Secondary outcomes included the frequency of regional lymph node metastases, the association between regional lymph node metastases and histopathological risk factors, and overall survival with or without right-sided hemicolectomy. Cox proportional hazards regression was used to estimate the relative all-cause mortality hazard associated with right-sided hemicolectomy compared with appendectomy alone. This study is registered with ClinicalTrials.gov, NCT03852693. FINDINGS: 282 patients with suspected appendiceal tumours were identified, of whom 278 with an appendiceal NET of 1-2 cm in size were included. 163 (59%) had an appendectomy and 115 (41%) had a right-sided hemicolectomy, 110 (40%) were men, 168 (60%) were women, and mean age at initial surgery was 36·0 years (SD 18·2). Median follow-up was 13·0 years (IQR 11·0-15·6). After centralised histopathological review, appendiceal NETs were classified as a possible or probable primary tumour in two (1%) of 278 patients with distant peritoneal metastases and in two (1%) 278 patients with distant metastases in the liver. All metastases were diagnosed synchronously with no tumour-related deaths during follow-up. Regional lymph node metastases were found in 22 (20%) of 112 patients with right-sided hemicolectomy with available data. On the basis of histopathological risk factors, we estimated that 12·8% (95% CI 6·5 -21·1) of patients undergoing appendectomy probably had residual regional lymph node metastases. Overall survival was similar between patients with appendectomy and right-sided hemicolectomy (adjusted hazard ratio 0·88 [95% CI 0·36-2·17]; p=0·71). INTERPRETATION: This study provides evidence that right-sided hemicolectomy is not indicated after complete resection of an appendiceal NET of 1-2 cm in size by appendectomy, that regional lymph node metastases of appendiceal NETs are clinically irrelevant, and that an additional postoperative exclusion of metastases and histopathological evaluation of risk factors is not supported by the presented results. These findings should inform consensus best practice guidelines for this patient cohort. FUNDING: Swiss Cancer Research foundation.

Incidence of Hepatocellular Carcinoma in Patients With Nonalcoholic Fatty Liver Disease: A Systematic Review, Meta-analysis, and Meta-regression.

BACKGROUND & AIMS: Nonalcoholic fatty liver disease (NAFLD) may be a risk factor for hepatocellular carcinoma (HCC), but the extent of this association still needs to be addressed. Pooled incidence rates of HCC across the disease spectrum of NAFLD have never been estimated by meta-analysis. METHODS: In this systematic review, we searched Web of Science, Embase, PubMed, and the Cochrane Library from January 1, 1950 through July 30, 2020. We included studies reporting on HCC incidence in patients with NAFLD. The main outcomes were pooled HCC incidences in patients with NAFLD at distinct severity stages. Summary estimates were calculated with random-effects models. Sensitivity analyses and meta-regression analyses were carried out to address heterogeneity. RESULTS: We included 18 studies involving 470,404 patients. In patients with NAFLD at a stage earlier than cirrhosis, the incidence rate of HCC was 0.03 per 100 person-years (95% confidence interval [CI], 0.01-0.07; I2 = 98%). In patients with cirrhosis, the incidence rate was 3.78 per 100 person-years (95% CI, 2.47-5.78; I2 = 93%). Patients with cirrhosis undergoing regular screening for HCC had an incidence rate of 4.62 per 100 person-years (95% CI, 2.77-7.72; I2 = 77%). CONCLUSIONS: Patients with NAFLD-related cirrhosis have a risk of developing HCC similar to that reported for patients with cirrhosis from other etiologies. Evidence documenting the risk in patients with nonalcoholic steatohepatitis or simple steatosis is limited, but the incidence of HCC in these populations may lie below thresholds used to recommend a screening. Well-designed prospective studies in these subpopulations are needed. The protocol for this systematic review is registered in the Prospero database (registration number CRD42018092861).

Impact of operation duration on postoperative outcomes of minimally-invasive right colectomy.

AIM: Operation time (OT) is a key operational factor influencing surgical outcomes. The present study aimed to analyse whether OT impacts on short-term outcomes of minimally-invasive right colectomies by assessing the role of surgical approach (robotic [RRC] or laparoscopic right colectomy [LRC]), and type of ileocolic anastomosis (i.e., intracorporal [IA] or extra-corporal anastomosis [EA]). METHODS: This was a retrospective analysis of the Minimally-invasivE surgery for oncological Right ColectomY (MERCY) Study Group database, which included adult patients with nonmetastatic right colon adenocarcinoma operated on by oncological RRC or LRC between January 2014 and December 2020. Univariate and multivariate analyses were used. RESULTS: The study sample was composed of 1549 patients who were divided into three groups according to the OT quartiles: (1) First quartile, <135 min (n = 386); (2) Second and third quartiles, 135-199 min (n = 731); and (3) Fourth quartile ≥200 min (n = 432). The majority (62.7%) were LRC-EA, followed by LRC-IA (24.3%), RRC-IA (11.1%), and RRC-EA (1.9%). Independent predictors of an OT ≥ 200 min included male gender, age, obesity, diabetes, use of indocyanine green fluorescence, and IA confection. An OT ≥ 200 min was significantly associated with an increased risk of postoperative noninfective complications (AOR: 1.56; 95% CI: 1.15-2.13; p = 0.004), whereas the surgical approach and the type of anastomosis had no impact on postoperative morbidity. CONCLUSION: Prolonged OT is independently associated with increased odds of postoperative noninfective complications in oncological minimally-invasive right colectomy.

Liver Transplantation Selection and Allocation Criteria for Hepatocellular Carcinoma: A European Perspective.

For patients with early-stage hepatocellular carcinoma (HCC), liver transplantation offers the best chance of cure. Over the past two decades, selection criteria to determine eligibility for liver transplantation have been constantly refined but a fair allocation strategy of liver grafts to HCC patients remains challenging. In Europe, over a dozen transplantation networks apply different liver transplantation criteria for HCC patients. In this review, we explore and compare candidate selection and liver graft allocation strategies for patients with HCC with a European perspective and discuss the ethical and technical challenges involved. In addition, we suggest possible paths for future improvement such as transitioning from fixed selection and allocation criteria to a more flexible model of benefit, which includes criteria concerning the graft, response to treatment, the biology of the tumor, and other relevant recipient factors.

Predicting recurrence of hepatocellular carcinoma after liver transplantation using a novel model that incorporates tumor and donor-related factors.

Evidence suggests that liver graft quality impacts on posttransplant recurrence of hepatocellular carcinoma (HCC). As of today, selection criteria only use variables related to tumor characteristics. Within the Scientific Registry of Transplant Recipients, we identified patients with HCC who underwent liver transplantation between 2004 and 2016 (development cohort, n = 10 887). Based on tumor recurrence rates, we fitted a competing-risk regression incorporating tumor- and donor-related factors, and we developed a prognostic score. Results were validated both internally and externally in the Australia and New Zealand Liver Transplant Registry. Total tumor diameter (subhazard ratio [sub-HR] 1.52 [1.28-1.81]), alpha-feto protein (sub-HR 1.27 [1.23-1.32], recipient male gender (sub-HR 1.43 [1.18-1.74]), elevated donor body mass index (sub-HR 1.26 [1.01-1.58]), and shared graft allocation policy (sub-HR 1.20 [1.01-1.43]) were independently associated with tumor recurrence. We next developed the Darlica score (sub-HR 2.72 [2.41-3.08] P < 0.001) that allows identifying risky combinations between a given donor and a given recipient. Results were validated internally (n = 3 629) and externally in the Australia and New Zealand Liver Transplant Registry (n = 370). The current score is based on variables that are readily available at the time of graft offer. It allows identifying hazardous donor-recipient combinations in terms of risk of tumor recurrence and overall survival.

Tolerogenic properties of liver macrophages in non-alcoholic steatohepatitis.

BACKGROUND & AIMS: Our understanding of non-alcoholic fatty liver disease (NAFLD) pathogenesis is improving, but there is still limited data on the function of resident liver macrophages in this context, especially when considering their contribution in dampening liver inflammation. METHODS: Liver macrophages were studied in mouse models of prolonged diet-induced liver steatohepatitis and carbon tetrachloride-induced liver injury. We assessed liver macrophages phenotype and costimulatory/inhibitory properties upon exposure to lipopolysaccharide or interleukin 4. We did phagocytosis and antigen presentation assays to investigate liver macrophages function as scavengers and immune response initiators. Using immunofluorescence staining, we further determined, in human liver tissue of patients with simple steatosis, non-alcoholic steatohepatitis and chronic hepatitis B infection, the expression of the co-inhibitory protein CD274 (Programmed-death ligand 1) and major histocompatibility complex (MHC) class II. RESULTS: Both in humans and mice, within chronically inflamed fatty livers, liver macrophages acquired immunomodulatory properties by reducing the expression of MHC class II, and by enhancing co-inhibitory signalling. Liver macrophages circumscribed endotoxin-mediated inflammatory response by upregulating anti-inflammatory genes arginase 1 and interleukin-10. While hepatic macrophages isolated from mice with normal livers were capable of achieving endotoxin tolerance, our results indicated an impairment of this protective mechanism in the presence NASH-like parenchymal abnormalities. CONCLUSIONS: Liver macrophages can achieve endotoxin tolerance, but in the chronically inflamed fatty liver, while they acquire an immunomodulatory phenotype, liver macrophages fail to dampen immune-mediated damage. Therefore, loss of tolerogenicity induced by ongoing liver insult may be a mechanism contributing to the worsening of NAFLD.

Antibody-induced NKG2D blockade in a rat model of intraportal islet transplantation leads to a deleterious reaction.

Intraportal islet transplantation is plagued by an acute destruction of transplanted islets. Amongst the first responders, NK cells and macrophages harbour an activating receptor, NKG2D, recognizing ligands expressed by stressed cells. We aimed to determine whether islet NKG2D ligand expression increases with culture time, and to analyse the impact of antibody-induced NKG2D blockade in islet transplantation. NKG2D-ligand expression was analysed in rat and human islets. Syngeneic marginal mass intraportal islet transplantations were performed in rats: control group, recipients transplanted with NKG2D-recombinant-treated islets (recombinant group), and recipients treated with a mouse anti-rat anti-NKG2D antibody and transplanted with recombinant-treated islets (antibody-recombinant group). Islets demonstrated increased gene expression of NKG2D ligands with culture time. Blockade of NKG2D on NK cells decreased in vitro cytotoxicity against islets. Recipients from the control and recombinant groups showed similar metabolic results; conversely, treatment with the antibody resulted in lower diabetes reversal. The antibody depleted circulating and liver NK cells in recipients, who displayed increased macrophage infiltration of recipient origin around the transplanted islets. In vitro blockade of NKG2D ligands had no impact on early graft function. Systemic treatment of recipients with an anti-NKG2D antibody was deleterious to the islet graft, possibly through an antibody-dependent cell-mediated cytotoxicity reaction.

Risk of Colorectal Cancer in Patients With Acute Diverticulitis: A Systematic Review and Meta-analysis of Observational Studies.

BACKGROUND & AIMS: We performed a systematic review and meta-analysis to assess the prevalence of colorectal cancer in patients with acute diverticulitis. METHODS: We searched MEDLINE from inception through November 2nd, 2017 for studies reporting the prevalence of colorectal cancer in patients with diverticulitis, identified based on the protocol CRD42017083272. This systematic review was conducted in accordance to the MOOSE guidelines. Pooled prevalence values were obtained by random effects models and robustness was tested by leave-one out sensitivity analyses. Heterogeneity was assessed using the Q-test and quantified based on I2 value. The critical appraisal of included studies was performed using the Newcastle-Ottawa scale. RESULTS: Our final analysis included 31 studies, comprising 50,445 patients. The pooled prevalence of colorectal cancer was 1.9% (95% CI, 1.5%-2.3%). Patients with complicated diverticulitis had a significantly higher risk for colorectal cancer (prevalence, 7.9%; 95% CI, 3.9%-15.3%) than patients with uncomplicated diverticulitis (prevalence, 1.3%; 95% CI, 0.1%-2%), corresponding to a pooled prevalence ratio of 6.7 (95% CI, 2.5-18.3). Subgroup analyses did not find significant difference in prevalence when separately pooling studies according to ranking on the Newcastle-Ottawa scale, geographical location or length of follow-up. Meta-regression did not find any association between age and colorectal cancer. Among patients who underwent endoscopy, the pooled prevalence of polyps was 22.7% (95% CI, 19.6%-26.0%), of advanced adenomas was 4.4% (95% CI, 3.4%-5.8%), of adenomas was 14.2% (95% CI, 11.7%-17.1%), and of hyperplastic polyps was 9.2% (95% CI, 7.6%-11.2%). CONCLUSION: In a meta-analysis of observational studies of patients with acute diverticulitis, we found the pooled prevalence of colorectal cancer to be 1.9%. The risk of colorectal cancer was significantly higher in patients with complicated diverticulitis than in patients with uncomplicated diverticulitis.

Effects of remote ischaemic preconditioning on intraportal islet transplantation in a rat model.

Remote ischaemic preconditioning (RIPC), which is the intermittent interruption of blood flow to a site distant from the target organ, is known to improve solid organ resistance to ischaemia-reperfusion injury. This procedure could be of interest in islet transplantation to mitigate hypoxia-related loss of islet mass after isolation and transplantation. Islets isolated from control or RIPC donors were analyzed for yield, metabolic activity, gene expression and high mobility group box-1 (HMGB1) content. Syngeneic marginal mass transplantation was performed in four streptozotocin-induced diabetic groups: control, RIPC in donor only, RIPC in recipient only, and RIPC in donor and recipient. Islets isolated from RIPC donors had an increased yield of 20% after 24 h of culture compared to control donors (P = 0.007), linked to less cell death (P = 0.08), decreased expression of hypoxia-related genes (Hif1a P = 0.04; IRP94 P = 0.008), and increased intra-cellular (P = 0.04) and nuclear HMGB1. The use of RIPC in recipients only did not allow for reversal of diabetes, with increased serum HMGB1 at day 1; the three other groups demonstrated significantly better outcomes. Performing RIPC in the donors increases islet yield and resistance to hypoxia. Validation is needed, but this strategy could help to decrease the number of donors per islet recipient.

Effects of the gut-liver axis on ischaemia-mediated hepatocellular carcinoma recurrence in the mouse liver.

BACKGROUND & AIMS: There is growing evidence that liver graft ischemia-reperfusion (I/R) is a risk factor for hepatocellular carcinoma (HCC) recurrence, but the mechanisms involved are unclear. Herein, we tested the hypothesis that mesenteric congestion resulting from portal blood flow interruption induces endotoxin-mediated Toll-like receptor 4 (Tlr4) engagement, resulting in elevated liver cancer burden. We also assessed the role of remote ischemic preconditioning (RIPC) in this context. METHODS: C57Bl/6j mice were exposed to standardized models of liver I/R injury and RIPC, induced by occluding the hepatic and femoral blood vessels. HCC was induced by injecting RIL-175 cells into the portal vein. We further evaluated the impact of the gut-liver axis (lipopolysaccharide (LPS)-Tlr4 pathway) in this context by studying mice with enhanced (lipopolysaccharide infusion) or defective (Tlr4-/- mice, gut sterilization, and Tlr4 antagonist) Tlr4 responses. RESULTS: Portal triad clamping provoked upstream mesenteric venous engorgement and increased bacterial translocation, resulting in aggravated tumor burden. RIPC prevented this mechanism by preserving intestinal integrity and reducing bacterial translocation, thereby mitigating HCC recurrence. These observations were linked to the LPS-Tlr4 pathway, as supported by the high and low tumor burden displayed by mice with enhanced or defective Tlr4 responses, respectively. CONCLUSIONS: Modulation of the gut-liver axis and the LPS-Tlr4 response by RIPC, gut sterilization, and Tlr4 antagonism represents a potential therapeutic target to prevent I/R lesions, and to alleviate HCC recurrence after liver transplantation and resection. LAY SUMMARY: Cancer recurrence can occur after liver resection or liver transplantation for hepatocellular carcinoma (HCC). This study suggests that intestinal venous congestion, which often occurs during liver surgery, favors the translocation of gut-derived bacterial products in the portal vein, thereby facilitating cancer recurrence by enhancing the signaling of Toll-like receptor 4 in the liver. Using a mouse model of HCC recurrence, we show that strategies that (i) reduce bacterial translocation (by gut decontamination, or by protecting the intestine from venous ischemia damage) or (ii) inhibit Tlr4 signaling in the liver, could reduce cancer recurrence.