Long-term ex situ normothermic machine perfusion allows regeneration of human livers with severe bile duct injury.

Bile duct regeneration is hypothesized to prevent biliary strictures, a leading cause of morbidity after liver transplantation. Assessing the capacity for biliary regeneration may identify grafts as suitable for transplantation that are currently declined, but this has been unfeasible until now. This study used long-term ex situ normothermic machine perfusion (LT-NMP) to assess biliary regeneration. Human livers that were declined for transplantation were perfused at 36 °C for up to 13.5 days. Bile duct biopsies, bile, and perfusate were collected throughout perfusion, which were examined for features of injury and regeneration. Biliary regeneration was defined as new Ki-67-positive biliary epithelium following severe injury. Ten livers were perfused for a median duration of 7.5 days. Severe bile duct injury occurred in all grafts, and biliary regeneration occurred in 70% of grafts. Traditional biomarkers of biliary viability such as bile glucose improved during perfusion but this was not associated with biliary regeneration (P > .05). In contrast, the maintenance of interleukin-6 and vascular endothelial growth factor-A levels in bile was associated with biliary regeneration (P = .017 for both cytokines). This is the first study to demonstrate biliary regeneration during LT-NMP and identify a cytokine signature in bile as a novel biomarker for biliary regeneration during LT-NMP.

Incidence, epidemiology, and outcomes of acute allograft rejection following liver transplantation in Australia.

Acute allograft rejection is a well-known complication of liver transplantation (LT). The incidence, epidemiology, and outcomes of acute rejection have not been well described in Australia. We retrospectively studied consecutive adults who underwent deceased donor LT at a single center between 2010 and 2020. Donor and recipient data at the time of LT and recipient outcomes were collected from a prospective LT database. Liver biopsy reports were reviewed, and only a graft's first instance of biopsy-proven acute rejection was analyzed. During the study period, 796 liver transplants were performed in 770 patients. Biopsy-proven rejection occurred in 34.9% of transplants. There were no significant changes in the incidence of rejection over time (linear trend p =0.11). The median time to the first episode of rejection was 71 days after LT: 2.2% hyperacute, 50.4% early (≤90 d), and 47.5% late rejection (>90 d). Independent risk factors for rejection were younger recipient age at transplant (aHR 0.98 per year increase, 95% CI: 0.97-1.00, p =0.01), and ABO-incompatible grafts (aHR 2.55 vs. ABO-compatible, 95% CI: 1.27-5.09, p <0.01) while simultaneous multiorgan transplants were protective (aHR 0.21 vs. LT only, 95% CI: 0.08-0.58, p <0.01). Development of acute rejection (both early and late) was independently associated with significantly reduced graft (aHR 3.13, 95% CI: 2.21-4.42, p <0.001) and patient survival (aHR 3.42, 95% CI: 2.35-4.98, p <0.001). In this 11-year Australian study, acute LT rejection occurred in 35%, with independent risk factors of younger recipient age and ABO-incompatible transplant, while having a simultaneous multiorgan transplant was protective. Acute rejection was independently associated with reduced graft and patient survival after adjustment for other factors.

Classification of Intrahepatic Cholangiocarcinoma into Perihilar Versus Peripheral Subtype.

BACKGROUND: Intrahepatic cholangiocarcinoma (ICC) constitutes a group of heterogeneous malignancies within the liver. We sought to subtype ICC based on anatomical origin of tumors, as well as propose modifications of the current classification system. METHODS: Patients undergoing curative-intent resection for ICC, hilar cholangiocarcinoma (CCA), or hepatocellular carcinoma (HCC) were identified from three international multi-institutional consortia of databases. Clinicopathological characteristics and survival outcomes were assessed. RESULTS: Among 1264 patients with ICC, 1066 (84.3%) were classified as ICC-peripheral subtype, whereas 198 (15.7%) were categorized as ICC-perihilar subtype. Compared with ICC-peripheral subtype, ICC-perihilar subtype was more often associated with aggressive tumor characteristics, including a higher incidence of nodal metastasis, macro- and microvascular invasion, perineural invasion, as well as worse overall survival (OS) (median: ICC-perihilar 19.8 vs. ICC-peripheral 37.1 months; p < 0.001) and disease-free survival (DFS) (median: ICC-perihilar 12.8 vs. ICC-peripheral 15.2 months; p = 0.019). ICC-perihilar subtype and hilar CCA had comparable OS (19.8 vs. 21.4 months; p = 0.581) and DFS (12.8 vs. 16.8 months; p = 0.140). ICC-peripheral subtype tumors were associated with more advanced tumor features, as well as worse survival outcomes versus HCC (OS, median: ICC-peripheral 37.1 vs. HCC 74.3 months; p < 0.001; DFS, median: ICC-peripheral 15.2 vs. HCC 45.5 months; p < 0.001). CONCLUSIONS: ICC should be classified as ICC-perihilar and ICC-peripheral subtype based on distinct clinicopathological features and survival outcomes. ICC-perihilar subtype behaved more like carcinoma of the bile duct (i.e., hilar CCA), whereas ICC-peripheral subtype had features and a prognosis more akin to a primary liver malignancy.

Recurrent Intrahepatic Cholangiocarcinoma: A 10-Point Score to Predict Post-Recurrence Survival and Guide Treatment of Recurrence.

INTRODUCTION: Although up to 50-70% of patients with intrahepatic cholangiocarcinoma (ICC) recur following resection, data to predict post-recurrence survival (PRS) and guide treatment of recurrence are limited. METHODS: Patients who underwent resection of ICC between 2000 and 2020 were identified from an international, multi-institutional database. Data on primary disease as well as laboratory and radiologic data on recurrent disease were collected. Factors associated with PRS were examined and a novel scoring system to predict PRS (PRS score) was developed and internally validated. RESULTS: Among 986 individuals who underwent resection for ICC, 588 (59.6%) patients developed recurrence at a median follow up of 20.3 months. Among patients who experienced a recurrence, 97 (16.5%) underwent re-resection/ablation for recurrent ICC; 88 (15.0%) and 403 (68.5%) patients received intra-arterial treatment or systemic chemotherapy/supportive therapy, respectively. Patient American Society of Anesthesiologists (ASA) class > 2 (1 point), primary tumor N1/Nx status (1 point), primary R1 resection margin (1 point), primary tumor G3/G4 grade (1 point), carbohydrate antigen (CA) 19-9 > 37 UI/mL (2 points) at recurrence and carcinoembryonic antigen (CEA) > 5 ng/mL (2 points) at recurrence, as well as recurrent bilateral disease (1 point) and early recurrence (1 point) were included in the PRS score. The PRS score successfully stratified patients relative to PRS and demonstrated strong discriminatory ability (C-index 0.70, 95% confidence interval 0.68-0.72). While a PRS score of 0-3 was associated with a 3-year PRS of 62.5% following resection/ablation for recurrent ICC, a PRS score > 3 was associated with a low 3-year PRS of 35.5% (p = 0.03). CONCLUSIONS: The PRS score demonstrated strong discriminatory ability to predict PRS among patients who had developed recurrence following initial resection of ICC. The PRS score may be a useful tool to guide treatment among patients with recurrent ICC.

Benchmarks in Liver Resection for Intrahepatic Cholangiocarcinoma.

INTRODUCTION: Benchmarking in surgery has been proposed as a means to compare results across institutions to establish best practices. We sought to define benchmark values for hepatectomy for intrahepatic cholangiocarcinoma (ICC) across an international population. METHODS: Patients who underwent liver resection for ICC between 1990 and 2020 were identified from an international database, including 14 Eastern and Western institutions. Patients operated on at high-volume centers who had no preoperative jaundice, ASA class <3, body mass index <35 km/m2, without need for bile duct or vascular resection were chosen as the benchmark group. RESULTS: Among 1193 patients who underwent curative-intent hepatectomy for ICC, 600 (50.3%) were included in the benchmark group. Among benchmark patients, median age was 58.0 years (interquartile range [IQR] 49.0-67.0), only 28 (4.7%) patients received neoadjuvant therapy, and most patients had a minor resection (n = 499, 83.2%). Benchmark values included ≥3 lymph nodes retrieved when lymphadenectomy was performed, blood loss ≤600 mL, perioperative blood transfusion rate ≤42.9%, and operative time ≤339 min. The postoperative benchmark values included TOO achievement ≥59.3%, positive resection margin ≤27.5%, 30-day readmission ≤3.6%, Clavien-Dindo III or more complications ≤14.3%, and 90-day mortality ≤4.8%, as well as hospital stay ≤14 days. CONCLUSIONS: Benchmark cutoffs targeting short-term perioperative outcomes can help to facilitate comparisons across hospitals performing liver resection for ICC, assess inter-institutional variation, and identify the highest-performing centers to improve surgical and oncologic outcomes.

Early Onset Intrahepatic Cholangiocarcinoma: Clinical Characteristics, Oncological Outcomes, and Genomic/Transcriptomic Features.

INTRODUCTION: Data on clinical characteristics and disease-specific prognosis among patients with early onset intrahepatic cholangiocarcinoma (ICC) are currently limited. METHODS: Patients undergoing hepatectomy for ICC between 2000 and 2020 were identified by using a multi-institutional database. The association of early (≤50 years) versus typical onset (>50 years) ICC with recurrence-free (RFS) and disease-specific survival (DSS) was assessed in the multi-institutional database and validated in an external cohort. The genomic and transcriptomic profiles of early versus late onset ICC were analyzed by using the Total Cancer Genome Atlas (TCGA) and Memorial Sloan Kettering Cancer Center databases. RESULTS: Among 971 patients undergoing resection for ICC, 22.7% (n = 220) had early-onset ICC. Patients with early-onset ICC had worse 5-year RFS (24.1% vs. 29.7%, p < 0.05) and DSS (36.5% vs. 48.9%, p = 0.03) compared with patients with typical onset ICC despite having earlier T-stage tumors and lower rates of microvascular invasion. In the validation cohort, patients with early-onset ICC had worse 5-year RFS (7.4% vs. 20.5%, p = 0.002) compared with individuals with typical onset ICC. Using the TCGA cohort, 652 and 266 genes were found to be upregulated (including ATP8A2) and downregulated (including UTY and KDM5D) in early versus typical onset ICC, respectively. Genes frequently implicated as oncogenic drivers, including CDKN2A, IDH1, BRAF, and FGFR2 were infrequently mutated in the early-onset ICC patients. CONCLUSIONS: Early-onset ICC has distinct clinical and genomic/transcriptomic features. Morphologic and clinicopathologic characteristics were unable to fully explain differences in outcomes among early versus typical onset ICC patients. The current study offers a preliminary landscape of the molecular features of early-onset ICC.

Development and Validation of a Predictive Risk Score for Blood Transfusion in Patients Undergoing Curative-Intent Surgery for Intrahepatic Cholangiocarcinoma.

BACKGROUND AND OBJECTIVES: Among patients undergoing liver resection for intrahepatic cholangiocarcinoma (ICC), perioperative bleeding requiring blood transfusion is a common complication, yet preoperative identification of patients at risk for transfusion remains challenging. The objective of this study was to develop a preoperative risk score for blood transfusion requirement during surgery for ICC. METHODS: Patients undergoing curative-intent liver surgery for ICC (1990-2020) were identified from a multi-institutional database. A predictive model was developed and validated. An easy-to-use risk calculator was made available online. RESULTS: Among 1420 patients, 300 (21.1%) received an intraoperative transfusion. Independent predictors of transfusion included severe preoperative anemia (OR = 1.65, 95% CI 1.10-2.47), T2 category or higher (OR = 2.00, 95% CI 1.36-3.02), positive lymph nodes (OR = 1.75, 95% CI 1.32-2.32) and major resection (OR = 2.56, 95%CI 1.85-3.58). Receipt of blood transfusion significantly correlated with worse outcomes. The model showed good discriminative ability in both training (AUC = 0.68, 95% CI 0.66-0.72) and bootstrapping validation (C-index = 0.67, 95% CI 0.65-0.70) cohorts. An online risk calculator of blood transfusion requirement was developed (https://catalano-giovanni.shinyapps.io/TransfusionRisk). CONCLUSIONS: Intraoperative blood transfusion was significantly associated with poor postoperative outcomes among patients undergoing surgery for ICC. The identification of patients at high risk of transfusion could improve perioperative patient care and blood resources allocation.

Long-term survivors after curative-intent resection for intrahepatic cholangiocarcinoma.

OBJECTIVES: The objective of the current study was to characterize prognostic factors related to long-term recurrence-free survival after curative-intent resection of intrahepatic cholangiocarcinoma (ICC). METHODS: Data on patients who underwent curative-intent resection for ICC between 2000 and 2020 were collected from an international multi-institutional database. Prognostic factors were investigated among patients who recurred within 5 years versus long-term survivors who survived more than 5 years with no recurrence. RESULTS: Among 635 patients who underwent curative-intent resection for ICC, 104 (16.4%) patients were long-term survivors with no recurrence beyond 5 years after surgery. Patients who survived for more than 5 years with no recurrence were more likely to have less aggressive tumor features, as well as have undergone an R0 resection versus patients who recurred within 5 years after resection. On multivariable analysis, tumor size (>5 cm) (HR: 1.535, 95% CI: 1.254-1.879), satellite lesions (HR: 1.253, 95% CI: 1.003-1.564), and lymph node metastasis (HR: 1.733, 95% CI: 1.349-2.227) were independently associated with recurrence within 5 years. Patients who recurred beyond 5 years (n = 23), 2-5 years (n = 60), and within 2 years (n = 471) had an incrementally worse post-recurrence survival (PRS, 28.0 vs. 20.0 vs. 12.0 months, p = 0.032). Among patients with N0 status, tumor size (>5 cm) (HR: 1.612, 95% CI: 1.087-2.390) and perineural invasion (PNI) (HR: 1.562,95% CI: 1.081-2.255) were risk factors associated with recurrence. Among patients with N1 disease, only a minority (5/128, 3.9%) of patients survived with no recurrence to 5 years. CONCLUSION: Roughly 1 in 6 patients survived for more than 5 years with no recurrence following curative-intent resection of ICC. Among N0 patients, tumor recurrence was associated with tumor size and PNI. Only a small subset of N1 patients experienced long-term survival.

Preoperative platelet count as an independent predictor of long-term outcomes among patients undergoing resection for intrahepatic cholangiocarcinoma.

BACKGROUND AND OBJECTIVES: An elevated platelet count may reflect neoplastic and inflammatory states, with cytokine-driven overproduction of platelets. The objective of this study was to evaluate the prognostic utility of high platelet count among patients undergoing curative-intent liver surgery for intrahepatic cholangiocarcinoma (ICC). METHODS: An international, multi-institutional cohort was used to identify patients undergoing curative-intent liver resection for ICC (2000-2020). A high platelet count was defined as platelets >300 *109/L. The relationship between preoperative platelet count, cancer-specific survival (CSS), and overall survival (OS) was examined. RESULTS: Among 825 patients undergoing curative-intent resection for ICC, 139 had a high platelet count, which correlated with multifocal disease, lymph nodes metastasis, poor to undifferentiated grade, and microvascular invasion. Patients with high platelet counts had worse 5-year (35.8% vs. 46.7%, p = 0.009) CSS and OS (24.8% vs. 39.8%, p < 0.001), relative to patients with a low platelet count. After controlling for relevant clinicopathologic factors, high platelet count remained an adverse independent predictor of CSS (HR = 1.46, 95% CI 1.02-2.09) and OS (HR = 1.59, 95% CI 1.14-2.22). CONCLUSIONS: High platelet count was associated with worse tumor characteristics and poor long-term CSS and OS. Platelet count represents a readily-available laboratory value that may preoperatively improve risk-stratification of patients undergoing curative-intent liver resection for ICC.

Hypothermic Oxygenated machine PErfusion for high-risk liver grafts for transplantation: A systematic review and meta-analysis.

BACKGROUND: Hypothermic Oxygenated machine PErfusion (HOPE) can reduce ischemic reperfusion injury and improve outcomes for liver transplant recipients. However, the effect of HOPE on high-risk extended criteria donor (ECD) and donation after circulatory death determination (DCDD) grafts is incomplete, despite the expectation that this cohort benefit maximally from HOPE. Accordingly, this paper aims to characterize the effect of HOPE on ECD and DCDD grafts. METHODS: This study includes all papers comparing HOPE to static cold storage for high-risk ECD and DCDD grafts. Systematic searches of Medline, Embase, and Scopus were completed using the terms "HOPE" OR "hypothermic oxygenated machine perfusion" AND "liver transplantation". Data were extracted and analyzed using IBM SPSS to perform the meta-analysis. RESULTS: A total of 2286 records were identified, with 10 meeting the inclusion criteria. Overall, the quality of evidence is heterogenous with many papers relying on retrospective controls. However, pooled analysis demonstrates HOPE to significantly reduce the rate of early allograft dysfunction, 12-month graft failure, re-transplantation, total biliary complications, and non-anastomotic strictures for high-risk grafts. CONCLUSIONS: There is good evidence that HOPE improves outcomes following liver transplantation across a number of biochemical and clinical endpoints for high-risk grafts. Of note, the reduction in biliary complications and re-transplantation is particularly significant given the morbidity associated with these endpoints. However, further, high-quality prospective trials with contemporary controls and clinically relevant primary endpoints are needed to better define the impact of HOPE for this cohort of grafts.

Incorporating a hemodialysis filter into a commercial normothermic perfusion system to facilitate long-term preservation of human split-livers.

BACKGROUND: Normothermic machine perfusion (NMP) allows for the assessment and resuscitation of ex-vivo human livers prior to transplantation. Commercially available NMP systems are closed circuits that accumulate metabolic waste and cytokines over time, potentially limiting organ preservation times. Dialysis has been proposed as a method to remove waste and excess fluid from such systems. This study aimed to demonstrate the utility of integrating dialysis into a commercially available system by quantifying solute removal. METHODS: A dialysis filter was attached in parallel to a commercially available liver perfusion system. Three livers declined for transplantation were split before undergoing long-term NMP with blood using the modified system. During perfusion, dialysate flow rates were set in the range of 100-600 mL/h for short periods of time. At each flow rate, perfusate and spent dialysate samples were collected and analyzed for solute clearance. RESULTS: The addition of dialysis to a commercial NMP system removed water-soluble waste and helped regulate electrolyte concentrations. Interleukin-6 was successfully removed from the perfusate. Solute clearance was proportional to dialysate flow rate. A guide for our perfusion setup was created for the appropriate selection of dialysis flow rates and duration based on real-time perfusate composition. CONCLUSIONS: Dialysis circuits can efficiently remove waste and regulate perfusate composition, and can be easily incorporated to improve the performance of commercially available systems. Quantification of the effect of dialysis on perfusate composition enables refined dialysis control to optimize electrolyte profiles and avoid the over- or under-correction of key solutes.

Indocyanine green: A novel marker for assessment of graft quality during ex situ normothermic machine perfusion of human livers.

BACKGROUND: Ex situ machine perfusion facilitates the assessment of livers prior to transplantation. However, currently available markers of liver function poorly predict long-term graft function. Indocyanine green (ICG) is a liver-specific dye which, although common in vivo, has never been comprehensively evaluated for the assessment of graft quality during ex situ machine perfusion. This study aimed to assess the utility of ICG in the ex situ setting. METHODS: Using a customized long-term perfusion system, human livers that were not suitable for transplantation were perfused using a red cell-based perfusate. ICG was delivered into the perfusate on days 0, 1, and 4 to assess ICG clearance (spectrophotometric absorbance at 805 nm) and ICG fluorescence (near-infrared camera). RESULTS: Sixteen partial livers were perfused for a median duration of 172 h (7.2 days). On day 0, the median ICG perfusate disappearance rate (PDR) was 7.5%/min and the median ICG retention at 15 min was 9.9%. Grafts that survived ≥7 days had a significantly higher median ICG PDR on day 0 (14.5%/min vs. 6.5%/min, p = 0.005) but not on days 1 or 4. ICG perfusion demonstrated that long-surviving grafts had a significantly lower median red-value (89.8 vs. 118.6, p = 0.011) and a significantly lower median blue-value (12.9 vs. 22.6, p = 0.045) than short-surviving grafts. CONCLUSION: ICG is a novel marker for the assessment of liver function during ex situ normothermic machine perfusion. ICG PDR and quantitative ICG perfusion can distinguish between long- and short-surviving grafts and demonstrate the utility of ICG in the assessment of graft quality prior to transplant.

Novel Dual Tracer Indocyanine Green and Radioisotope Versus Gold Standard Sentinel Lymph Node Biopsy in Breast Cancer: The GREENORBLUE Trial.

BACKGROUND: The methods for sentinel lymph node (SLN) biopsy in breast cancer have been variable in type and number of tracers. Some units have abandoned the use of blue dye (BD) due to adverse reactions. Fluorescence-guided biopsy with indocyanine green (ICG) is a relatively novel technique. This study compared the clinical efficacy and costs between novel dual tracer ICG and radioisotope (ICG-RI) with "gold standard" BD and radioisotope (BD-RI). METHODS: Single-surgeon study of 150 prospective patients with early breast cancer undergoing SLN biopsy (2021-2022) using ICG-RI compared with a retrospective cohort of 150 consecutive previous patients using BD-RI. Number of SLNs identified, rate of failed mapping, identification of metastatic SLNs, and adverse reactions were compared between techniques. Cost-minimisation analysis performed by using Medicare item numbers and micro-costing analysis. RESULTS: Total number of SLNs identified with ICG-RI and BD-RI was 351 and 315, respectively. Mean number of SLNs identified with ICG-RI and BD-RI was 2.3 (standard deviation [SD] 1.4) and 2.1 (SD 1.1), respectively (p = 0.156). There were no cases of failed mapping with either dual technique. Metastatic SLNs were identified in 38 (25.3%) ICG-RI patients compared with 30 (20%) BD-RI patients (p = 0.641). There were no adverse reactions to ICG, whereas four cases of skin tattooing and anaphylaxis were associated with BD (p = 0.131). ICG-RI cost an additional AU$197.38 per case in addition to the initial cost for the imaging system. CLINICAL TRIAL REGISTRATION:  ACTRN12621001033831. CONCLUSIONS: Novel tracer combination, ICG-RI, provided an effective and safe alternative to "gold standard" dual tracer. The caveat was the significantly greater costs associated with ICG.

Lymph Node Examination and Patterns of Nodal Metastasis Among Patients with Left- Versus Right-Sided Intrahepatic Cholangiocarcinoma After Major Curative-Intent Resection.

BACKGROUND: We sought to investigate whether the unique lateral patterns of lymphatic drainage impacted lymphadenectomy (LND), lymph node metastasis (LNM), and long-term survival of patients after curative hemi-hepatectomy for left- versus right-sided intrahepatic cholangiocarcinoma (ICC). METHODS: Data on patients who underwent curative hemi-hepatectomy for left- or right-sided ICC were collected from 15 high-volume centers worldwide, as well as from the Surveillance, Epidemiology, and End Results (SEER) registry. Primary outcomes included overall survival (OS) and disease-free survival (DFS). RESULTS: Among 697 patients identified from the multi-institutional database, patients who underwent hemi-hepatectomy for left-sided ICC (n = 363, 52.1%) were more likely to have an increased number of LND versus patients with right-sided ICC (n = 334, 47.9%) (median, left 5 versus right 3, p = 0.012), although the frequency (left 66.4% versus right 63.8%, p = 0.469) and station (beyond station no. 12, left 25.3% versus right 21.1%, p = 0.293) were similar. Consequently, left-sided ICC was associated with higher incidence of LNM (left 33.3% versus right 25.7%, p = 0.036), whereas the station and number of LNM were not different (both p > 0.1). There was no difference in OS (median, left 34.9 versus right 29.6 months, p = 0.130) or DFS (median, left 14.5 versus right 15.2 months, p = 0.771) among patients who underwent hemi-hepatectomy for left- versus right-sided ICC, which were also verified in the SEER dataset. LNM beyond station no. 12 was associated with even worse long-term survival versus LNM within station no. 12 among patients with either left- or right-sided ICC after curative-intent resection (all p < 0.05). CONCLUSIONS: The unique lateral patterns of lymphatic drainage were closely related to utilization of LND, as well as LNM of left- versus right-sided ICC.

Development and Validation of a Machine-Learning Model to Predict Early Recurrence of Intrahepatic Cholangiocarcinoma.

BACKGROUND: The high incidence of early recurrence after hepatectomy for intrahepatic cholangiocarcinoma (ICC) has a detrimental effect on overall survival (OS). Machine-learning models may improve the accuracy of outcome prediction for malignancies. METHODS: Patients who underwent curative-intent hepatectomy for ICC were identified using an international database. Three machine-learning models were trained to predict early recurrence (< 12 months after hepatectomy) using 14 clinicopathologic characteristics. The area under the receiver operating curve (AUC) was used to assess their discrimination ability. RESULTS: In this study, 536 patients were randomly assigned to training (n = 376, 70.1%) and testing (n = 160, 29.9%) cohorts. Overall, 270 (50.4%) patients experienced early recurrence (training: n = 150 [50.3%] vs testing: n = 81 [50.6%]), with a median tumor burden score (TBS) of 5.6 (training: 5.8 [interquartile range {IQR}, 4.1-8.1] vs testing: 5.5 [IQR, 3.7-7.9]) and metastatic/undetermined nodes (N1/NX) in the majority of the patients (training: n = 282 [75.0%] vs testing n = 118 [73.8%]). Among the three different machine-learning algorithms, random forest (RF) demonstrated the highest discrimination in the training/testing cohorts (RF [AUC, 0.904/0.779] vs support vector machine [AUC, 0.671/0.746] vs logistic regression [AUC, 0.668/0.745]). The five most influential variables in the final model were TBS, perineural invasion, microvascular invasion, CA 19-9 lower than 200 U/mL, and N1/NX disease. The RF model successfully stratified OS relative to the risk of early recurrence. CONCLUSIONS: Machine-learning prediction of early recurrence after ICC resection may inform tailored counseling, treatment, and recommendations. An easy-to-use calculator based on the RF model was developed and made available online.

Higher Tumor Burden Status Dictates the Impact of Surgical Margin Status on Overall Survival in Patients Undergoing Resection of Intrahepatic Cholangiocarcinoma.

BACKGROUND: The present study aimed to examine the prognostic significance of margin status following hepatectomy of intrahepatic cholangiocarcinoma (ICC) relative to overall tumor burden and nodal status. METHOD: Patients who underwent curative-intent surgery for ICC between 1990 and 2017 were included from a multi-institutional database. The impact of margin status and width on overall survival (OS) was examined relative to TBS and preoperative nodal status. RESULTS: Among 1105 patients with ICC who underwent resection, median tumor burden score (TBS) was 6.1 (IQR 4.2-8.8) and 218 (19.7%) patients had N1 disease. More than one in eight patients had an R1 surgical margin (n = 154, 13.9%). Among patients with low or medium TBS, an increasing margin width was associated with an incrementally improved 5-year OS (R1 31.9% vs. 1-3 mm 38.5% vs. 3-10 mm 48.0% vs. ≥ 10 mm 52.3%). In contrast, among patients with a high TBS, margin width was not associated with better survival (R1 28.9% vs. 1-3 mm 22.8% vs. 3-10 mm 29.6% vs. ≥ 10 mm 13.7%). In addition, surgical margin status did not impact survival with cutoffs of TBS 7 or greater. Furthermore, patients with low or medium TBS and preoperative negative lymph nodes derived a survival benefit from an R0 resection (R1 resection, HR 2.15, 95% CI 1.35-3.44, p = 0.001). In contrast, margin status was not associated with prognosis among patients with a high TBS and preoperative positive/suspicious lymph nodes (R1 resection, HR 1.34, 95% CI 0.58-3.11, p = 0.50). CONCLUSION: R0 resection and wider margin resection resulted in improved outcomes in patients with low tumor burden; however, the survival benefit of negative margin status disappeared in patients with underlying poor tumor biology.

Long-Term Recurrence-Free and Overall Survival Differ Based on Common, Proliferative, and Inflammatory Subtypes After Resection of Intrahepatic Cholangiocarcinoma.

INTRODUCTION: While generally associated with poor prognosis, intrahepatic cholangiocarcinoma (ICC) can have a heterogeneous presentation and natural history. We sought to identify specific ICC subtypes that may be associated with varied long-term outcomes and patterns of recurrence after liver resection. METHODS: Patients who underwent curative-intent resection for ICC from 2000 to 2020 were identified from a multi-institutional database. Hierarchical cluster analysis characterized three ICC subtypes based on morphology (i.e., tumor burden score [TBS]) and biology (i.e., preoperative neutrophil-to-lymphocyte ratio [NLR] and CA19-9 levels). RESULTS: Among 598 patients, the cluster analysis identified three ICC subtypes: Common (n = 300, 50.2%) (median, TBS: 4.5; NLR: 2.4; CA19-9: 38.0 U/mL); Proliferative (n = 246, 41.1%) (median, TBS: 8.8; NLR: 2.9; CA19-9: 71.2 U/mL); Inflammatory (n = 52, 8.7%) (median, TBS: 5.4; NLR: 12.6; CA19-9: 26.7 U/mL). Median overall survival (OS) (Common: 72.0 months; Proliferative: 31.4 months; Inflammatory: 22.9 months) and recurrence-free survival (RFS) (Common: 21.5 months; Proliferative: 11.9 months; Inflammatory: 9.0 months) varied considerably among the different ICC subtypes (all p < 0.001). Even though patients with Inflammatory ICC had more favorable T-(T1/T2, Common: 84.4%; Proliferative: 80.6%; Inflammatory: 86.5%) and N-(N0, Common: 14.0%; Proliferative: 20.7%; Inflammatory: 26.9%) disease, the Inflammatory subtype was associated with a higher incidence of intra- and extrahepatic recurrence (Common: 15.8%; Proliferative: 24.2%; Inflammatory: 28.6%) (all p = 0.01). CONCLUSIONS: Cluster analysis identified three distinct subtypes of ICC based on TBS, NLR, and CA19-9. ICC subtype was associated with RFS and OS and predicted worse outcomes among patients. Despite more favorable T- and N-disease, the Inflammatory ICC subtype was associated with worse outcomes ICC subtype should be considered in the prognostic stratification of patients.

Application of Hazard Function to Investigate Recurrence of Intrahepatic Cholangiocarcinoma After Curative-Intent Liver Resection: A Novel Approach to Characterize Recurrence.

PURPOSE: To investigate recurrence patterns after surgery for intrahepatic cholangiocarcinoma (ICC) relative to lymph node status, tumor extension, tumor burden score (TBS), and adjuvant chemotherapy. METHODS: Patients who underwent curative-intent resection for ICC from 1990 to 2020 were enrolled from a multi-institutional database. The hazard function was applied to plot the hazard rates over time, with further stratification by T and N AJCC 8th edition categories, TBS, and adjuvant chemotherapy. RESULTS: A total of 1192 patients underwent curative-intent resection for ICC and 59.9% experienced recurrence. Overall, the peak of recurrence occurred at 6.6 months. Among patients with negative lymph nodes, the T4-category had a higher peak rate of recurrence (0.1199 at 10.2 months) compared with other T-categories, while high TBS had an earlier peak of recurrence (4.2 months) compared with lower TBS. Among patients with N1 disease, T2-T4 categories had multipeak patterns of recurrence with higher hazard rates during the first 3 years after surgery in comparison with T1-category, while patients with high TBS had an earlier (4.0 months) and higher hazard peak rate compared with lower TBS groups. The administration of adjuvant chemotherapy was associated with delayed hazard rates of recurrence for N1 (4 months) and NX (6 months) categories. DISCUSSION: The novel application of the hazard function to assess hazard rates and timing patterns of recurrence following resection for ICC demonstrated that recurrence varied based on T- and N-categories, as well as TBS. Hazard function-based recurrence data may be helpful to tailor counseling, surveillance, and adjuvant therapy recommendations.

The Application of Artificial Intelligence to Investigate Long-Term Outcomes and Assess Optimal Margin Width in Hepatectomy for Intrahepatic Cholangiocarcinoma.

BACKGROUND: Intrahepatic cholangiocarcinoma (ICC) is associated with poor long-term outcomes, and limited evidence exists on optimal resection margin width. This study used artificial intelligence to investigate long-term outcomes and optimal margin width in hepatectomy for ICC. METHODS: The study enrolled patients who underwent curative-intent resection for ICC between 1990 and 2020. The optimal survival tree (OST) was used to investigate overall (OS) and recurrence-free survival (RFS). An optimal policy tree (OPT) assigned treatment recommendations based on random forest (RF) counterfactual survival probabilities associated with each possible margin width between 0 and 20 mm. RESULTS: Among 600 patients, the median resection margin was 4 mm (interquartile range [IQR], 2-10). Overall, 379 (63.2 %) patients experienced recurrence with a 5-year RFS of 28.3 % and a 5-year OS of 38.7 %. The OST identified five subgroups of patients with different OS rates based on tumor size, a carbohydrate antigen 19-9 [CA19-9] level higher than 200 U/mL, nodal status, margin width, and age (area under the curve [AUC]: training, 0.81; testing, 0.69). The patients with tumors smaller than 4.8 cm and a margin width of 2.5 mm or greater had a relative increase in 5-year OS of 37 % compared with the entire cohort. The OST for RFS estimated a 46 % improvement in the 5-year RFS for the patients younger than 60 years who had small (<4.8 cm) well- or moderately differentiated tumors without microvascular invasion. The OPT suggested five optimal margin widths to maximize the 5-year OS for the subgroups of patients based on age, tumor size, extent of hepatectomy, and CA19-9 levels. CONCLUSIONS: Artificial intelligence OST identified subgroups within ICC relative to long-term outcomes. Although tumor biology dictated prognosis, the OPT suggested that different margin widths based on patient and disease characteristics may optimize ICC long-term survival.

Safety of laparoscopic repair of incisional hernias in liver transplant recipients.

INTRODUCTION: Incisional hernia is a common complication following liver transplantation occurring in 5%-34% of patients. Traditionally, open repair was standard due to fear of abdominal adhesions, postoperative complications and lack of experience with laparoscopic techniques. Laparoscopic incisional hernia repair (LIHR) has now become routine in non-transplant patients, with improved postoperative outcomes. In this study, we compared outcomes after laparoscopic and open incisional hernia repair after liver transplantation at a high-volume liver transplant center. METHODS: We performed a retrospective cohort study including all incisional hernia repairs performed on post-liver transplant patients at a major liver transplant center in Australia from 2010 to 2021. Donor, recipient, intraoperative and postoperative variables were collected from the electronic medical record focusing on laparoscopic and open repairs. RESULTS: Between January 2010 and March 2021, 138 patients underwent incisional hernia repair: 40 laparoscopic (29%) and 98 open (71%). No difference in wound infection (2.5% vs. 7.7%, p = .243); wound dehiscence (.00% vs. 2.3%, p = .332) or hernia recurrence (16.3% vs. 23.0%, p = .352) was seen between treatment groups. For larger incisional hernias (>5 cm) we found that a laparoscopic repair reduced length of stay compared to open-repair (3.89 vs. 4.57 days, p = .026). CONCLUSION: Laparoscopic repair of larger incisional hernias reduced postoperative length of hospital stay, whilst potential advantages may include reduced wound complications and hernia recurrence. Importantly, laparoscopic repair did not increase postoperative complication rates and represents a safe technique for repair in this demographic.