Liver transplantation as an alternative for the treatment of non-resectable liver colorectal cancer: Advancing the therapeutic algorithm.

Colorectal cancer is a leading cause of cancer-related mortality, with nearly half of the affected patients developing liver metastases. For three decades, liver resection (LR) has been the primary curative strategy, yet its applicability is limited to about 20% of cases. Liver transplantation (LT) for unresectable metastases was attempted unsuccessfully in the 1990s, with high rates of perioperative death and recurrence. There is now more interest in this strategy due to improvements in systemic therapies and surgical techniques. A significant study conducted by the Oslo group showed that patients receiving liver transplants had a 60% chance of survival after five years. Significantly better results have been achieved by using advanced imaging for risk stratification and further refining selection criteria, especially in the Norvegian SECA trials. This review carefully charts the development and history of LT as a treatment option for colorectal cancer liver metastases. The revolutionary path from the early days of exploratory surgery to the current situation of cautious optimism is traced, highlighting the critical clinical developments and improved patient selection standards that have made LT a potentially curative treatment for such challenging very well selected cases.

A Global Overview on the Evolution, Debate, and Research Output on Liver Transplant Perfusion Machines.

OBJECTIVES: Machine perfusion of liver grafts has gained popularity for its abilities to preserve liver grafts,reduce cold storage damage, and evaluate graft viability before transplant. However, debate persists regarding the optimal solutions, logistics, and biomarkers for assessing graft quality. To shed light on the lengthy debates surrounding the use of machine perfusion in liver graft preservation,this study utilized bibliometric analysis to evaluate the status and development trends of main research areas. MATERIALS AND METHODS: On December 10th, 2022, we conducted a literature search using the Web of Science database to identify articles related to liver machine perfusion. The search included only original studies and reviews and excluded meeting abstracts, letters, notes, editorials, short surveys, book chapters, and errata. We identified the number of citations and encompassed various aspects, such as annual trends, countries, institutions, authors, journals, and key words. We used VOSviewer version 1.6.18 to generate tables and figures. RESULTS: After manually removing irrelevant papers, we included 264 articles (89 reviews; remaining were original studies). The articles were cited 5743 times, averaging 21.92 per article. We found that the United Kingdom (n = 76) was the country that produced the most articles,followed by theUnited States (66 articles). Most papers in our search were published in Liver Transplantation (n = 31) and Transplantation (n = 16). CONCLUSIONS: Bibliometric analysis provided insights into debates and advancements in liver graft preservation using machine perfusion. The analysis showed leading countries and key research areas in the field. This overview serves as a valuable resource for researchers, offering a foundation for further exploration and guiding future investigations in the field of machine perfusion for liver graft preservation.

Predicting futility of upfront surgery in perihilar cholangiocarcinoma: Machine learning analytics model to optimize treatment allocation.

BACKGROUND: While resection remains the only curative option for perihilar cholangiocarcinoma, it is well known that such surgery is associated with a high risk of morbidity and mortality. Nevertheless, beyond facing life-threatening complications, patients may also develop early disease recurrence, defining a "futile" outcome in perihilar cholangiocarcinoma surgery. The aim of this study is to predict the high-risk category (futile group) where surgical benefits are reversed and alternative treatments may be considered. METHODS: The study cohort included prospectively maintained data from 27 Western tertiary referral centers: the population was divided into a development and a validation cohort. The Framingham Heart Study methodology was used to develop a preoperative scoring system predicting the "futile" outcome. RESULTS: A total of 2271 cases were analyzed: among them, 309 were classified within the "futile group" (13.6%). American Society of Anesthesiology (ASA) score ≥ 3 (OR 1.60; p = 0.005), bilirubin at diagnosis ≥50 mmol/L (OR 1.50; p = 0.025), Ca 19-9 ≥ 100 U/mL (OR 1.73; p = 0.013), preoperative cholangitis (OR 1.75; p = 0.002), portal vein involvement (OR 1.61; p = 0.020), tumor diameter ≥3 cm (OR 1.76; p < 0.001), and left-sided resection (OR 2.00; p < 0.001) were identified as independent predictors of futility. The point system developed, defined three (ie, low, intermediate, and high) risk classes, which showed good accuracy (AUC 0.755) when tested on the validation cohort. CONCLUSIONS: The possibility to accurately estimate, through a point system, the risk of severe postoperative morbidity and early recurrence, could be helpful in defining the best management strategy (surgery vs. nonsurgical treatments) according to preoperative features.

The Leading Transplantation Journals: A Trend Analysis, 2011-2021.

Background: As the field of transplantation has expanded, so have the quantity and variety of articles published on the topic. Evaluation of publications and journals is crucial to the expansion of transplant research. This study investigated the research output and journal metrics of the leading solid organ transplant journals published between 2011 and 2021 based on estimations of the trends in the category CiteScore from the Scopus database. Materials and Methods: We obtained data on the listed journals from the Scopus Source List. We then filtered the list for "Transplantation" journals. Only the top quartiles or quartile 1 (Q1) journals were placed in this category. This study focused specifically on transplantation journals and did not include other journals related to diseases of transplanted organs such as the kidney, liver, heart, and lungs. Results: The number of transplantation journals increased by 42.8% in the last ten years, from 28 in 2011 to 40 in 2021. Between 2011 and 2021, nine transplantation journals ranked in the highest quartile (Q1). The American Journal of Transplantation was the top journal in both years, with a 150% increase in citations and an 11.2% increase in articles published. Open access (OA) transplant journals rose from 3 in 2011 to 10 in 2021. In 2021, OA journals earned 8,555 citations, a 125% increase from 2011. Despite this increase, non-OA journals received more citations than OA in 2021 (p value 0.026). Conclusion: Solid organ transplantation advances lead to more publications and citations. Regular journals and publications evaluation benefits academics and policymakers by promoting the growth of research. This study examined solid organ transplantation journals and gave a global perspective on transplant journal rankings and compared their status in 2011 and 2021.

Management of Established Small-for-size Syndrome in Post Living Donor Liver Transplantation: Medical, Radiological, and Surgical Interventions: Guidelines From the ILTS-iLDLT-LTSI Consensus Conference.

Small-for-size syndrome (SFSS) following living donor liver transplantation is a complication that can lead to devastating outcomes such as prolonged poor graft function and possibly graft loss. Because of the concern about the syndrome, some transplants of mismatched grafts may not be performed. Portal hyperperfusion of a small graft and hyperdynamic splanchnic circulation are recognized as main pathogenic factors for the syndrome. Management of established SFSS is guided by the severity of the presentation with the initial focus on pharmacological therapy to modulate portal flow and provide supportive care to the patient with the goal of facilitating graft regeneration and recovery. When medical management fails or condition progresses with impending dysfunction or even liver failure, interventional radiology (IR) and/or surgical interventions to reduce portal overperfusion should be considered. Although most patients have good outcomes with medical, IR, and/or surgical management that allow graft regeneration, the risk of graft loss increases dramatically in the setting of bilirubin >10 mg/dL and INR>1.6 on postoperative day 7 or isolated bilirubin >20 mg/dL on postoperative day 14. Retransplantation should be considered based on the overall clinical situation and the above postoperative laboratory parameters. The following recommendations focus on medical and IR/surgical management of SFSS as well as considerations and timing of retransplantation when other therapies fail.

ChatGPT and Artificial Intelligence in Transplantation Research: Is It Always Correct?

INTRODUCTION: ChatGPT (OpenAI, San Francisco, California, United States) is a chatbot powered by language-based artificial intelligence (AI). It generates text based on the information provided by users. It is currently being evaluated in medical research, publishing, and healthcare. However, there has been no prior study on the evaluation of its ability to help in kidney transplant research. This feasibility study aimed to evaluate the application and accuracy of ChatGPT in the field of kidney transplantation. METHODS: On two separate dates, February 21 and March 2, 2023, ChatGPT 3.5 was questioned regarding the medical treatment of kidney transplants and related scientific facts. The responses provided by the chatbot were compiled, and a panel of two specialists reviewed the correctness of each answer. RESULTS: We demonstrated that ChatGPT possessed substantial general knowledge of kidney transplantation; however, they lacked sufficient information and had inaccurate information that necessitates a deeper understanding of the topic. Moreover, ChatGPT failed to provide references for any of the scientific data it provided regarding kidney transplants, and when requested for references, it provided inaccurate ones. CONCLUSION: The results of this short feasibility study indicate that ChatGPT may have the ability to assist in data collecting when a particular query is posed. However, caution should be exercised and it should not be used in isolation as a supplement to research or decisions regarding healthcare because there are still challenges with data accuracy and missing information.

Prevalence, management and efficacy of treatment in portal vein obstruction after paediatric liver transplantation: protocol of the retrospective international multicentre PORTAL registry.

INTRODUCTION: Portal vein obstruction (PVO) consists of anastomotic stenosis and thrombosis, which occurs due to a progression of the former. The aim of this large-scale international study is to assess the prevalence, current management practices and efficacy of treatment in patients with PVO. METHODS AND ANALYSIS: The Portal vein Obstruction Revascularisation Therapy After Liver transplantation registry will facilitate an international, retrospective, multicentre, observational study, with 25 centres around the world already actively involved. Paediatric patients (aged <18 years) with a diagnosed PVO between 1 January 2001 and 1 January 2021 after liver transplantation will be eligible for inclusion. The primary endpoints are the prevalence of PVO, primary and secondary patency after PVO intervention and current management practices. Secondary endpoints are patient and graft survival, severe complications of PVO and technical success of revascularisation techniques. ETHICS AND DISSEMINATION: Medical Ethics Review Board of the University Medical Center Groningen has approved the study (METc 2021/072). The results of this study will be disseminated via peer-reviewed publications and scientific presentations at national and international conferences. TRIAL REGISTRATION NUMBER: Netherlands Trial Register (NL9261).

Suspected focal nodular hyperplasia in male adults: 10-year experience from a large liver centre.

PURPOSE: Focal nodular hyperplasia (FNH) is commonly found in females of reproductive age. In males, the diagnosis is made more cautiously due to its lower incidence and higher incidence of hepatocellular carcinoma, which can have overlapping imaging features. Follow-up or biopsy is sometimes required. This retrospective study aims to assess management of suspected FNH in male adult patients at our institution over a 10-year period. METHODS: Male adults (≥ 18 years) suspected of having FNH from January 2010-June 2020 were identified using a departmental radiology information system search. Data was collected from radiology reports and patient pathway manager. RESULTS: Of 342 patients with suspected FNH, 62 were male (18.1%; F:M of 4.5:1). We only included patients investigated and followed up by MRI, total of 57 patients. Median age was 40 years (range 18-74 years). Background liver disease present in 21/57 (36.8%), majority with hepatic steatosis. Average number of lesions per patient 1.7. 22/57 (38.6%) had at least one MRI follow-up using liver-specific contrast with 7 lesions demonstrating variation in size (range growth: -3.27 mm/year to + 4 mm/year). In 7 cases, MRI was not definitive; 6 required biopsy and 1 resection. Only 2/7 demonstrated malignancy. Of the total 57 patients, 6 have deceased and none due to a misdiagnosed or mismanaged hepatic lesion. CONCLUSION: FNH is relatively uncommon in males, however, our data suggests that lesions with typical MRI characteristics do not require follow-up and diagnosis can be made confidently, similar to females. Any atypical features should prompt a biopsy.

Long-term outcomes of pediatric liver transplantation in acute liver failure vs end-stage chronic liver disease: A retrospective observational study.

BACKGROUND: Children with acute liver failure (ALF) who meet the criteria are eligible for super-urgent transplantation, whereas children with end-stage chronic liver disease (ESCLD) are usually transplanted electively. Pediatric liver trans plantation (PLT) in ALF and ESCLD settings has been well described in the literature, but there are no studies comparing the outcomes in these two groups. AIM: To determine if there is a difference in post-operative complications and survival outcomes between ALF and ESCLD in PLT. METHODS: This was a retrospective observational study of all primary PLTs performed at a single center between 2000 and 2019. ALF and ESCLD groups were compared for pretransplant recipient, donor and operative parameters, and post-operative outcomes including graft and patient survival. RESULTS: Over a 20-year study period, 232 primary PLTs were performed at our center; 195 were transplanted for ESCLD and 37 were transplanted for ALF. The ALF recipients were significantly older (median 8 years vs 5.4 years; P = 0.031) and heavier (31 kg vs 21 kg; P = 0.011). Living donor grafts were used more in the ESCLD group (34 vs 0; P = 0.006). There was no difference between the two groups concerning vascular complications and rejection, but there were more bile leaks in the ESCLD group. Post-transplant patient survival was significantly higher in the ESCLD group: 1-, 5-, and 10-year survival rates were 97.9%, 93.9%, and 89.4%, respectively, compared to 78.3%, 78.3%, and 78.3% in the ALF group (P = 0.007). However, there was no difference in 1-, 5-, and 10-year graft survival between the ESCLD and ALF groups (90.7%, 82.9%, 77.3% vs 75.6%, 72.4%, and 66.9%; P = 0.119). CONCLUSION: Patient survival is inferior in ALF compared to ESCLD recipients; the main reason is death in the 1st year post-PLT in ALF group. Once the ALF children overcome the 1st year after transplant, their survival stabilizes, and they have good long-term outcomes.

Liver transplantation for isolated unresectable colorectal liver metastases - Protocol for a service evaluation in the United Kingdom - UKCoMET study.

BACKGROUND: Liver transplantation (LT) for unresectable colorectal liver metastases (CRCLM) demonstrates good overall survival for selected patients in contemporary studies, with 5-year survival of 80%. A Fixed Term Working Group (FTWG), set up by NHS Blood and Transplant (NHSBT) Liver Advisory Group (LAG), advised whether CRCLM should be considered for LT in United Kingdom. Their recommendation was that LT may be undertaken for isolated and unresectable CRCLM using strict selection criteria as a national clinical service evaluation. METHODS: Opinions were sought from colorectal cancer/LT patient representatives, experts in colorectal cancer surgery/oncology, LT surgery, hepatology, hepatobiliary radiology, pathology, and nuclear medicine, and appropriate patient selection criteria, referral and transplant listing pathways were identified. RESULTS: This paper summarises selection criteria for LT in United Kingdom for isolated and unresectable CRCLM patients, and highlights referral framework and pre-transplant assessment criteria. Finally, oncology-specific outcome measures to be utilised for assessing applicability of LT are described. CONCLUSION: This service evaluation represents a significant development for colorectal cancer patients in United Kingdom and a meaningful step forward in the field of transplant oncology. This paper details the protocol for the pilot study, scheduled to begin in the fourth quarter of 2022 in United Kingdom.

United Kingdom criteria for liver transplantation in the setting of isolated unresectable colorectal liver metastases.

AIM: Studies have demonstrated that liver transplantation may be an effective treatment for isolated unresectable colorectal cancer liver metastases (CRCLM). Published data suggest that 5-year survival may be as high as 80%; however, recurrent disease is commonplace. Consequently, the Liver Transplantation for Unresectable Colorectal Liver Metastases Fixed Term Working Unit recommended to the NHS Blood and Transplant Liver Advisory Group that while CRCLM is an appropriate indication for transplantation, selection criteria should be conservative and that it should be undertaken within a clinical service evaluation programme. The aim of this work is to outline the proposed UK selection criteria and follow-up process for CRCLM transplantation. METHOD: Consensus statement by colorectal cancer/liver transplantation patient representatives, experts in colorectal cancer surgery/oncology, liver transplantation surgery, hepatology, hepatobiliary radiology, hepatobiliary pathology and nuclear medicine. RESULTS: This study provides a comprehensive outline of the inclusion/exclusion criteria for referral in the UK. Furthermore, the referral framework is also explained. Pretransplant assessment criteria for listing/delisting are outlined. Finally, the oncology-specific outcome measures posttransplant are described. CONCLUSION: It is anticipated this service will begin in December 2022. A series of educational events for the referrers and transplant units will be arranged throughout 2023 to highlight CRCLM as a newly accepted UK indication for transplantation. A national audit will be undertaken to identify patients currently on treatment who meet the criteria for transplant. Data will be collected in a national registry and reviewed on an ongoing basis to confirm the safety of this treatment and to determine if the inclusion criteria require revision.

Unveiling transplantation research productivity of United States: A bibliometric analysis.

BACKGROUND: The United States has witnessed significant advancements in the field of organ transplantation over the course of the last five decades, as demonstrated by a notable increase in the quantity of academic research. The presence of a highly dynamic research environment necessitates continuous evaluations to maintain the integrity and progress of the field. AIM: To evaluate the total output and thematic emphasis of transplant research conducted in the United States. METHODS: On January 10, 2023, we conducted a bibliometric search of United States research output in transplantation journals from the Web of Science database's Science Citation Index Expanded. We excluded editorials, meeting abstracts, and other non-article types. We analyzed annual trends, authors, institutions, articles, keywords, and countries collaborating with the United States, using VOSviewer 1.6.18 to create figures and tables. RESULTS: The United States published 25956 papers (3078 reviews and 22878 articles) representing 37.7% of the world's scientific output. Canada emerged as the top collaborator with the United States, co-authoring 1263 articles. Leading institutions in United States transplantation research were the University of Pittsburgh (1749 articles), Mayo Clinic (1605 articles), Harvard Medical School (1549 articles), and Johns Hopkins University (1280 articles). The top three keywords with over 2000 occurrences were "recipients," "survival," and "outcomes," indicating a focus on graft and recipient outcome markers by United States researchers. CONCLUSION: Our findings demonstrate the United States leadership in organ transplantation research, contributing significantly to the global scientific output in this field. However, opportunities exist for fostering expansive partnerships, particularly with developing countries. This study provides valuable insights into the transplantation research landscape in the United States, emphasizing the importance of ongoing evaluations to maintain and propel advancements in this critical medical discipline. The results may facilitate future collaborations, knowledge exchange, and the pursuit of innovative solutions in the realm of organ transplantation.

Volume and flow modulation strategies to mitigate post-hepatectomy liver failure.

Introduction: Post hepatectomy liver failure is the most common cause of death following major hepatic resections with a perioperative mortality rate between 40% to 60%. Various strategies have been devised to increase the volume and function of future liver remnant (FLR). This study aims to review the strategies used for volume and flow modulation to reduce the incidence of post hepatectomy liver failure. Method: An electronic search was performed of the MEDLINE, EMBASE and PubMed databases from 2000 to 2022 using the following search strategy "Post hepatectomy liver failure", "flow modulation", "small for size flow syndrome", "portal vein embolization", "dual vein embolization", "ALPPS" and "staged hepatectomy" to identify all articles published relating to this topic. Results: Volume and flow modulation strategies have evolved over time to maximize the volume and function of FLR to mitigate the risk of PHLF. Portal vein with or without hepatic vein embolization/ligation, ALPPS, and staged hepatectomy have resulted in significant hypertrophy and kinetic growth of FLR. Similarly, techniques including portal flow diversion, splenic artery ligation, splenectomy and pharmacological agents like somatostatin and terlipressin are employed to reduce the risk of small for size flow syndrome SFSF syndrome by decreasing portal venous flow and increasing hepatic artery flow at the same time. Conclusion: The current review outlines the various strategies of volume and flow modulation that can be used in isolation or combination in the management of patients at risk of PHLF.

Outcomes After Liver Transplantation With Incidental Cholangiocarcinoma.

Cholangiocarcinoma (CCA) is currently a contraindication to liver transplantation (LT) in the United Kingdom (UK). Incidental CCA occurs rarely in some patients undergoing LT. We report on retrospective outcomes of patients with incidental CCA from six UK LT centres. Cases were identified from pathology records. Data regarding tumour characteristics and post-transplant survival were collected. CCA was classified by TNM staging and anatomical location. 95 patients who underwent LT between 1988-2020 were identified. Median follow-up after LT was 2.1 years (14 days-18.6 years). Most patients were male (68.4%), median age at LT was 53 (IQR 46-62), and the majority had underlying PSC (61%). Overall median survival after LT was 4.4 years. Survival differed by tumour site: 1-, 3-, and 5-year estimated survival was 82.1%, 68.7%, and 57.1%, respectively, in intrahepatic CCA (n = 40) and 58.5%, 42.6%, and 30.2% in perihilar CCA (n = 42; p = 0.06). 1-, 3-, and 5-year estimated survival was 95.8%, 86.5%, and 80.6%, respectively, in pT1 tumours (28.2% of cohort), and 65.8%, 44.7%, and 31.1%, respectively, in pT2-4 (p = 0.018). Survival after LT for recipients with incidental CCA is inferior compared to usual outcomes for LT in the United Kingdom. LT for earlier stage CCA has similar survival to LT for hepatocellular cancer, and intrahepatic CCAs have better survival compared to perihilar CCAs. These observations may support LT for CCA in selected cases.

Portal vein embolization versus dual vein embolization for management of the future liver remnant in patients undergoing major hepatectomy: meta-analysis.

BACKGROUND: This meta-analysis aimed to compare progression to surgery, extent of liver hypertrophy, and postoperative outcomes in patients planned for major hepatectomy following either portal vein embolization (PVE) or dual vein embolization (DVE) for management of an inadequate future liver remnant (FLR). METHODS: An electronic search was performed of MEDLINE, Embase, and PubMed databases using both medical subject headings (MeSH) and truncated word searches. Articles comparing PVE with DVE up to January 2022 were included. Articles comparing sequential DVE were excluded. ORs, risk ratios, and mean difference (MD) were calculated using fixed and random-effects models for meta-analysis. RESULTS: Eight retrospective studies including 523 patients were included in the study. Baseline characteristics between the groups, specifically, age, sex, BMI, indication for resection, and baseline FLR (ml and per cent) were comparable. The percentage increase in hypertrophy was larger in the DVE group, 66 per cent in the DVE group versus 27 per cent in the PVE group, MD 39.07 (9.09, 69.05) (P = 0.010). Significantly fewer patients failed to progress to surgery in the DVE group than the PVE group, 13 per cent versus 25 per cent respectively OR 0.53 (0.31, 0.90) (P = 0.020). Rates of post-hepatectomy liver failure 13 per cent versus 22 per cent (P = 0.130) and major complications 20 per cent versus 28 per cent (Clavien-Dindo more than IIIa) (P = 0.280) were lower. Perioperative mortality was lower with DVE, 1 per cent versus 10 per cent (P = 0.010). CONCLUSION: DVE seems to produce a greater degree of hypertrophy of the FLR than PVE alone which translates into more patients progressing to surgery. Higher quality studies are needed to confirm these results.

Towards Autonomous Robotic Minimally Invasive Ultrasound Scanning and Vessel Reconstruction on Non-Planar Surfaces.

Autonomous robotic Ultrasound (US) scanning has been the subject of research for more than 2 decades. However, little work has been done to apply this concept into a minimally invasive setting, in which accurate force sensing is generally not available and robot kinematics are unreliable due to the tendon-driven, compliant robot structure. As a result, the adequate orientation of the probe towards the tissue surface remains unknown and the anatomy reconstructed from scan may become highly inaccurate. In this work we present solutions to both of these challenges: an attitude sensor fusion scheme for improved kinematic sensing and a visual, deep learning based algorithm to establish and maintain contact between the organ surface and the US probe. We further introduce a novel scheme to estimate and orient the probe perpendicular to the center line of a vascular structure. Our approach enables, for the first time, to autonomously scan across a non-planar surface and navigate along an anatomical structure with a robotically guided minimally invasive US probe. Our experiments on a vessel phantom with a convex surface confirm a significant improvement of the reconstructed curved vessel geometry, with our approach strongly reducing the mean positional error and variance. In the future, our approach could help identify vascular structures more effectively and help pave the way towards semi-autonomous assistance during partial hepatectomy and the potential to reduce procedure length and complication rates.

Does ALT Correlate with Survival After Liver Resection for Colorectal Liver Metastases?

Background: The pringle manoeuvre is commonly used during hepatectomy, which may cause ischaemia-reperfusion injury and transient liver dysfunction. Post-operative liver transaminases are often used to assess ischaemia-reperfusion injury, although there is conflicting evidence on survival outcomes. The primary aim was to assess post-operative alanine aminotransferase (ALT) with survival outcomes. Secondary aims were to assess ALT level with the length of stay and overall complications. Methods: Post-operative day 2 ALT levels of five times the upper limit of normal (i.e. 280 U/L) were considered as clinically significant transaminitis. Kaplan-Meier survival curves were studied using log-rank analysis to identify the predictors of overall survival (OS) and recurrence-free survival (RFS). Results: Out of 752 patients who underwent hepatectomy, 527 (70.1%) patients had low ALT (<280 U/L) and 225 (29.9%) patients had high ALT on day 2 post-op. Post-operative ALT did not affect OS (P = 0.883) or RFS (P = 0.063). Factors associated with a worse OS and RFS on multivariate analysis were pre-operative chemotherapy, number of tumours and largest tumour size (>4 cm). A high post-operative ALT was not associated with the increased length of stay or more complications. Conclusions: Post-operative ALT does not affect survival outcomes post-hepatectomy for colorectal liver metastases.