Charting the Path Forward for Risk Prediction in Liver Transplant for Hepatocellular Carcinoma: International Validation of HALTHCC Among 4,089 Patients

Continuous Risk Score Predicts Waitlist and Post-transplant Outcomes in Hepatocellular Carcinoma Despite Exception Changes

BACKGROUND & AIMS

Continuous risk-stratification of candidates and urgency-based prioritization have been utilized for liver transplantation (LT) in patients with non-hepatocellular carcinoma (HCC) in the United States. Instead, for patients with HCC, a dichotomous criterion with exception points is still used. This study evaluated the utility of the hazard associated with LT for HCC (HALT-HCC), an oncological continuous risk score, to stratify waitlist dropout and post-LT outcomes.

METHODS

A competing risk model was developed and validated using the UNOS database (2012-2021) through multiple policy changes. The primary outcome was to assess the discrimination ability of waitlist dropouts and LT outcomes. The study focused on the HALT-HCC score, compared with other HCC risk scores.

RESULTS

Among 23,858 candidates, 14,646 (59.9%) underwent LT and 5196 (21.8%) dropped out of the waitlist. Higher HALT-HCC scores correlated with increased dropout incidence and lower predicted 5-year overall survival after LT. HALT-HCC demonstrated the highest area under the curve (AUC) values for predicting dropout at various intervals post-listing (0.68 at 6 months, 0.66 at 1 year), with excellent calibration (R2 = 0.95 at 6 months, 0.88 at 1 year). Its accuracy remained stable across policy periods and locoregional therapy applications.

CONCLUSIONS

This study highlights the predictive capability of the continuous oncological risk score to forecast waitlist dropout and post-LT outcomes in patients with HCC, independent of policy changes. The study advocates integrating continuous scoring systems like HALT-HCC in liver allocation decisions, balancing urgency, organ utility, and survival benefit.

Expanding Selection Criteria in Deceased Donor Liver Transplantation for Hepatocellular Carcinoma: Long-term Follow-up of a National Registry and 2 Transplant Centers

BACKGROUND

This study compares selection criteria for liver transplant (LT) for hepatocellular carcinoma (HCC) for inclusivity and predictive ability to identify the most permissive criteria that maintain patient outcomes.

METHODS

The Scientific Registry of Transplant Recipients (SRTR) database was queried for deceased donor LT's for HCC (2003-2020) with 3-y follow-up; these data were compared with a 2-center experience. Milan, University of California, San Francisco (UCSF), 5-5-500, Up-to-seven (U7), HALT-HCC, and Metroticket 2.0 scores were calculated.

RESULTS

Nationally, 26 409 patients were included, and 547 at the 2 institutions. Median SRTR-follow-up was 6.8 y (interquartile range 3.9-10.1). Three criteria allowed the expansion of candidacy versus Milan: UCSF (7.7%, n = 1898), Metroticket 2.0 (4.2%, n = 1037), and U7 (3.5%, n = 828). The absolute difference in 3-y overall survival (OS) between scores was 1.5%. HALT-HCC (area under the curve [AUC] = 0.559, 0.551-0.567) best predicted 3-y OS although AUC was notably similar between criteria (0.506 < AUC < 0.527, Mila n = 0.513, UCSF = 0.506, 5-5-500 = 0.522, U7 = 0.511, HALT-HCC = 0.559, and Metroticket 2.0 = 0.520), as was Harrall's c-statistic (0.507 < c-statistic < 0.532). All scores predicted survival to P < 0.001 on competing risk analysis. Median follow-up in our enterprise was 9.8 y (interquartile range 7.1-13.3). U7 (13.0%, n = 58), UCSF (11.1%, n = 50), HALT-HCC (6.4%, n = 29), and Metroticket 2.0 (6.3%, n = 28) allowed candidate expansion. HALT-HCC (AUC = 0.768, 0.713-0.823) and Metroticket 2.0 (AUC = 0.739, 0.677-0.801) were the most predictive of recurrence. All scores predicted recurrence and survival to P < 0.001 using competing risk analysis.

CONCLUSIONS

Less restrictive criteria such as Metroticket 2.0, UCSF, or U7 allow broader application of transplants for HCC without sacrificing outcomes. Thus, the criteria for Model for End-stage Liver Disease-exception points for HCC should be expanded to allow more patients to receive life-saving transplantation.

Evolution of transplant oncology indications: a single-institution experience over 40 years

Liver transplantation (LT) for uncommon tumoral indications has changed across the decades, with impaired results reported in the first historical series mainly for non-tumoral-related causes. Recently, renewed interest in liver transplant oncology has been reported. The study aims to analyze a mono-center experience exploring the evolution and the impact on patient survival of LT in uncommon tumoral indications. A retrospective analysis of 851 LT performed during 1982-2023 was investigated. 33/851 (3.9%) uncommon tumoral indications were reported: hepatocellular carcinoma (HCC) on non-cirrhotic liver (n = 14), peri-hilar (phCCA) (n = 8) and intrahepatic cholangiocarcinoma (i-CCA) (n = 3), metastatic disease (n = 4), hepatic hemangioendothelioma (n = 2), and benign tumor (n = 2). Uncommon tumoral indications were mainly transplanted during the period 1982-1989, with a complete disappearance after the year 2000 and a slight rise in the last years. Poor outcomes were reported: 5-year survival rates were 28.6%, 25.0%, 0%, and 0% in the case of HCC on non-cirrhotic liver, phCCA, i-CCA, and metastases, respectively. However, the cause of patient death was often related to non-tumoral conditions. LT for uncommon oncological diseases has increased worldwide in recent decades. Historical series report poor survival outcomes despite more recent data showing promising results. Hence, the decision to transplant these patients should be under the risk and overall benefit of the patient. The results of the ongoing protocol studies are expected to confirm the validity of the unconventional tumor indications.

Development and comprehensive validation of a predictive prognosis model for very early HCC recurrence within one year after curative resection: a multicenter cohort study

BACKGROUND

The high incidence of early recurrence after liver resection (LR) for hepatocellular carcinoma (HCC) is the main obstacle in achieving good long-term survival outcomes. The aim of the present study is to develop a prognostic model in predicting the risk of very early (1-year) recurrence.

MATERIAL AND METHODS

Consecutive patients who underwent LR for HCC with curative intent at multicenters in China were enrolled in this study. The VERM-pre (the Preoperative Very Early Recurrence Model of HCC) with good performance was derived and validated by internal and external cohorts retrospectively and by another two-center cohort prospectively.

RESULTS

Seven thousand four hundred one patients were enrolled and divided randomly into three cohorts. Eight variables (tumor diameter, tumor number, macrovascular invasion, satellite nodule, alpha-fetoprotein, level of HBV-DNA, γ-GT, and prothrombin time) were identified as independent risk factors for recurrence-free survival on univariate and multivariate analyses. The VERM-pre model was developed which showed a high capacity of discrimination (C-index: 0.722; AUROC at 1-year: 0.722)) and was validated comprehensively by the internal, external, and prospective cohorts, retrospectively. Calibration plots showed satisfactory fitting of probability of early HCC recurrence in the cohorts. Three risk strata were derived to have significantly different recurrence-free survival rates (low-risk: 80.4-85.4%; intermediate-risk: 59.7-64.8%; high-risk: 32.6-42.6%). In the prospective validation cohort, the swimming plot illustrated consistent outcomes with the beginning predictive score.

CONCLUSION

The VERM-pre model accurately predicted the 1-year recurrence rates of HCC after LR with curative intent. The model was retrospectively and prospectively validated and then developed as the online tool.

Emerging and Clinically Accepted Biomarkers for Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related death and the sixth most diagnosed malignancy worldwide. Serum alpha-fetoprotein (AFP) is the traditional, ubiquitous biomarker for HCC. However, there has been an increasing call for the use of multiple biomarkers to optimize care for these patients. AFP, AFP-L3, and prothrombin induced by vitamin K absence II (DCP) have described clinical utility for HCC, but unfortunately, they also have well established and significant limitations. Circulating tumor DNA (ctDNA), genomic glycosylation, and even totally non-invasive salivary metabolomics and/or micro-RNAS demonstrate great promise for early detection and long-term surveillance, but still require large-scale prospective validation to definitively validate their clinical validity. This review aims to provide an update on clinically available and emerging biomarkers for HCC, focusing on their respective clinical strengths and weaknesses.

Liver transplantation meets gastrointestinal cancer

Liver transplantation (LT) has emerged as a standard of care for patients with end-stage liver disease, providing a life-saving intervention for patients with severely compromised liver function in both the acute and chronic setting. While LT has also become a routine procedure for early-stage hepatocellular carcinoma (HCC), offering a potential cure by treating both the tumor and the underlying liver disease, its relevance in the context of other malignancies such as cholangiocellular carcinoma (CCA), combined hepatocellular-cholangiocarcinoma (cHCC-CCA) or liver metastases is still the subject of intense debate and no definite recommendations have yet been established. This review summarizes the current therapeutic standards in the context of LT for gastrointestinal malignancies and provides a reflection and outlook on current scientific and clinical developments.

Risk of Recurrence of Hepatocarcinoma after Liver Transplantation: Performance of Recurrence Predictive Models in a Cohort of Transplant Patients

Liver transplantation (LT) is a curative treatment for early-stage hepatocellular carcinoma (HCC) unsuitable for surgical resection. However, tumor recurrence (TR) rates range from 8% to 20% despite strict selection criteria. The validation of new prognostic tools, such as pre-MORAL or RETREAT risks, is necessary to improve recurrence prediction. A retrospective study was conducted at Marqués de Valdecilla University Hospital in Cantabria, Spain, between 2010 and 2019 to determine the rate of TR in LT patients and identify associated factors. Patients with liver-kidney transplantation, re-transplantation, HIV infection, survival less than 90 days, or incidental HCC were excluded. Data on demographic, liver disease-related, LT, and tumor-related variables, as well as follow-up records, including TR and death, were collected. TR was analyzed using the Log-Rank test, and a multivariate Cox regression analysis was performed. The study was approved by the IRB of Cantabria. TR occurred in 13.6% of LT patients (95% CI = 7.3-23.9), primarily as extrahepatic recurrence (67%) within the first 5 years (75%). Increased TR was significantly associated with higher Body Mass Index (BMI) (HR = 1.3 [95% CI = 1.1-1.5]), vascular micro-invasion (HR = 8.8 [1.6-48.0]), and medium (HR = 20.4 [3.0-140.4]) and high pre-MORAL risk (HR = 30.2 [1.6-568.6]). TR also showed a significant correlation with increased mortality. Conclusions: LT for HCC results in a 13.6% rate of tumor recurrence. Factors such as BMI, vascular micro-invasion, and medium/high pre-MORAL risk are strongly associated with TR following LT.

Rescue liver transplantation after post-hepatectomy acute liver failure: A systematic review and pooled analysis

BACKGROUND

Post-hepatectomy liver failure is a severe complication after major liver resection and is associated with a high mortality rate. Nevertheless, there is no effective treatment for severe liver failure. In such a setting, rescue liver transplantation (LT) is used only in extraordinary cases with unclear results. This systematic review aims to define indication of LT in post-hepatectomy liver failure and post-LT outcomes, in terms of patient and disease-free survivals, to assess the procedure's feasibility and effectiveness.

METHODS

A systematic review of all English language full-text articles published until September 2022 was conducted. Inclusion criteria were articles describing patients undergoing LT for post-hepatectomy liver failure after liver resection, which specified at least one outcome of interest regarding patient/graft survival, postoperative complications, tumour recurrence and cause of death. A pseudo-individual participant data meta-analysis was performed to analyse data. Study quality was assessed with MINORS system. PROSPERO CRD42022349358.

RESULTS

Postoperative complication rate was 53.6%. All patients transplanted for benign indications survived. For malignant tumours, 1-, 3- and 5-year overall survival was 94.7%, 82.1% and 74.6%, respectively. The causes of death were tumour recurrence in 83.3% of cases and infection-related in 16.7% of LT recipients. At Cox regression, being transplanted for unconventional malignant indications (colorectal liver metastasis, cholangiocarcinoma) was a risk factor for death HR = 8.93 (95%CI = 1.04-76.63; P-value = 0.046). Disease-free survival differs according to different malignant tumours (P-value = 0.045).

CONCLUSIONS

Post-hepatectomy liver failure is an emergent indication for rescue LT, but it is not universally accepted. In selected patients, LT can be a life-saving procedure with low short-term risks. However, special attention must be given to long-term oncological prognosis before proceeding with rescue LT in an urgent setting, considering the severity of liver malignancy, organ scarcity, the country's organ allocation policies and the resource of living-related donation.

Radiographic tumor burden score is useful for stratifying the overall survival of hepatocellular carcinoma patients undergoing resection at different Barcelona Clinic Liver Cancer stages

PURPOSE

The Barcelona Clinic Liver Cancer (BCLC) staging system has been recommended for prognostic prediction. However, prognosis is variable at different BCLC stages. We aimed to evaluate whether the radiographic tumor burden score (TBS) could be used to stratify prognosis in different BCLC stages.

METHODS

Hepatocellular carcinoma (HCC) patients undergoing liver resection (LR) at BCLC-0, -A, or -B stage in our institution in 2007-2018 were divided into derivation and validation cohorts. Overall survival (OS) was analyzed according to the TBS and BCLC stage. TBS cutoff values for OS were determined with X-tile.

RESULTS

Of the 749 patients in the derivation cohort, 138 (18.4%) had BCLC-0, 542 (72.3%) BCLC-A, and 69 (9.2%) BCLC-B HCC; 76 (10.1%) had a high TBS (> 7.9), 477 (63.7%) a medium TBS (2.6-7.9), and 196 (26.2%) a low TBS (< 2.6). OS worsened progressively with increasing TBS in the cohort (p < 0.001) and in BCLC-A (p = 0.04) and BCLC-B (p = 0.002) stages. Multivariate analysis showed that the TBS was associated with OS of patients with BCLC-A (medium vs. low TBS: hazard ratio [HR] = 2.390, 95% CI = 1.024-5.581, p = 0.04; high vs. low TBS: HR = 3.885, 95% CI = 1.443-10.456, p = 0.007) and BCLC-B (high vs. medium TBS: HR = 2.542, 95% CI = 1.077-6.002, p = 0.033) HCC. The TBS could also be used to stratify the OS of patients in the validation cohort (p < 0.001).

CONCLUSION

The TBS could be used to stratify the OS of the entire cohort and BCLC stages A and B of HCC patients undergoing LR.

AFP score and metroticket 2.0 perform similarly and could be used in a "within-ALL" clinical decision tool

Background & Aims

Two recently developed composite models, the alpha-fetoprotein (AFP) score and Metroticket 2.0, could be used to select patients with hepatocellular carcinoma (HCC) who are candidates for liver transplantation (LT). The aim of this study was to compare the predictive performance of both models and to evaluate the net risk reclassification of post-LT recurrence between them using each model's original thresholds.

Methods

This multicenter cohort study included 2,444 adult patients who underwent LT for HCC in 47 centers from Europe and Latin America. A competing risk regression analysis estimating sub-distribution hazard ratios (SHRs) and 95% CIs for recurrence was used (Fine and Gray method). Harrell's adapted c-statistics were estimated. The net reclassification index for recurrence was compared based on each model's original thresholds.

Results

During a median follow-up of 3.8 years, there were 310 recurrences and 496 competing events (20.3%). Both models predicted recurrence, HCC survival and survival better than Milan criteria (p <0.0001). At last tumor reassessment before LT, c-statistics did not significantly differ between the two composite models, either as original or threshold versions, for recurrence (0.72 vs. 0.68; p = 0.06), HCC survival, and overall survival after LT. We observed predictive gaps and overlaps between the model's thresholds, and no significant gain on reclassification. Patients meeting both models ("within-ALL") at last tumor reassessment presented the lowest 5-year cumulative incidence of HCC recurrence (7.7%; 95% CI 5.1-11.5) and higher 5-year post-LT survival (70.0%; 95% CI 64.9-74.6).

Conclusions

In this multicenter cohort, Metroticket 2.0 and the AFP score demonstrated a similar ability to predict HCC recurrence post-LT. The combination of these composite models might be a promising clinical approach.

Impact and implications

Composite models were recently proposed for the selection of liver transplant (LT) candidates among individuals with hepatocellular carcinoma (HCC). We found that both the AFP score and Metroticket 2.0 predicted post-LT HCC recurrence and survival better than Milan criteria; the Metroticket 2.0 did not result in better reclassification for transplant selection compared to the AFP score, with predictive gaps and overlaps between the two models; patients who met low-risk thresholds for both models had the lowest 5-year recurrence rate. We propose prospectively testing the combination of both models, to further optimize the LT selection process for candidates with HCC.

The liver transplant surgeon Mondays blues: an Italian perspective

Poor data exist on the influence of holidays and weekdays on the number and the results of liver transplantation (LT) in Italy. The study's main objective is to investigate the impact of holidays and the different days of the week on the LT number and early graft survival rates in a multi-centric Italian series. We performed a retrospective analysis on 1,026 adult patients undergoing first deceased-donor transplantation between January 2004 and December 2018 in the three university centers in Rome. During the 4,504 workdays, 881 LTs were performed (85.9%; one every 5.1 days on average). On the opposite, 145 LTs were done during the 975 holidays (14.1%; one every 7.1 days on average). Fewer LTs were performed on holidays (P = 0.004). There were no substantial differences in donor-, recipient- and transplant-related characteristics in LTs performed on weekdays or holidays. On Monday, fewer transplants were performed (vs. other weekdays: P < 0.0001; vs. Sunday: P = 0.03). At multivariable Cox regression analysis, LTs performed during the holiday or during the different days of the week were not found to be independent risk factors for the risk of 3- and 12-month graft loss. At three-month survival curves, no differences were observed among the transplants performed during the holidays versus the workdays (86.2 vs. 85.0%; P-0.70). The range of graft survival rates based on the day of the week was 81.6-86.9%, without showing any significant differences (P = 0.57). Fewer transplants are performed on holidays and Mondays. Survivals are not affected by holidays or the day the transplant is performed.

The impact of biological features for a better prediction of posttransplant hepatocellular cancer recurrence

PURPOSE OF REVIEW

Morphological criteria (i.e., Milan Criteria) have been considered for a long time to be the best tool for selecting patients with hepatocellular cancer (HCC) waiting for liver transplantation (LT). In the last ten years, a refinement of the selection criteria has been observed, with the introduction of biological tumor characteristics enabling to enlarge the number of potential transplant candidates and to select LT candidates with a lower risk of posttransplant recurrence.

RECENT FINDINGS

Several biological tumor aspects have been explored and validated in international cohorts to expand the ability to predict patients at high risk for recurrence. Alpha-fetoprotein, radiological response to locoregional treatments, and other more recently proposed markers have been principally explored. Moreover, more complex statistical approaches (i.e., deep learning) have been advocated to explore the nonlinear intercorrelations between the investigated features.

SUMMARY

The addition of biological aspects to morphology has improved the ability to discriminate among high- and low-risk patients for recurrence. New prognostic algorithms based on the more sophisticated artificial intelligence approach are further improving the capability to select LT candidates with HCC.

The Toronto Postliver Transplantation Hepatocellular Carcinoma Recurrence Calculator: A Machine Learning Approach

Liver transplantation (LT) listing criteria for hepatocellular carcinoma (HCC) remain controversial. To optimize the utility of limited donor organs, this study aims to leverage machine learning to develop an accurate posttransplantation HCC recurrence prediction calculator. Patients with HCC listed for LT from 2000 to 2016 were identified, with 739 patients who underwent LT used for modeling. Data included serial imaging, alpha-fetoprotein (AFP), locoregional therapies, treatment response, and posttransplantation outcomes. We compared the CoxNet (regularized Cox regression), survival random forest, survival support vector machine, and DeepSurv machine learning algorithms via the mean cross-validated concordance index. We validated the selected CoxNet model by comparing it with other currently available recurrence risk algorithms on a held-out test set (AFP, Model of Recurrence After Liver Transplant [MORAL], and Hazard Associated with liver Transplantation for Hepatocellular Carcinoma [HALT-HCC score]). The developed CoxNet-based recurrence prediction model showed a satisfying overall concordance score of 0.75 (95% confidence interval [CI], 0.64-0.84). In comparison, the recalibrated risk algorithms' concordance scores were as follows: AFP score 0.64 (outperformed by the CoxNet model, 1-sided 95% CI, >0.01; P = 0.04) and MORAL score 0.64 (outperformed by the CoxNet model 1-sided 95% CI, >0.02; P = 0.03). The recalibrated HALT-HCC score performed well with a concordance of 0.72 (95% CI, 0.63-0.81) and was not significantly outperformed (1-sided 95% CI, ≥0.05; P = 0.29). Developing a comprehensive posttransplantation HCC recurrence risk calculator using machine learning is feasible and can yield higher accuracy than other available risk scores. Further research is needed to confirm the utility of machine learning in this setting.

Liver Transplantation for Hepatocellular Carcinoma: How Should We Improve the Thresholds?

Simple Summary

The ideal treatment for hepatocellular carcinoma (HCC) is liver transplantation (LT), which both eliminates the HCC and cures the diseased liver. Once considered an experimental treatment with dismal survival rates, LT for HCC entered a new era with the establishment of the Milan criteria over 20 years ago. However, over the last two decades, the Milan criteria, which are based on tumor morphology, have come under intense scrutiny and are now largely regarded as too restrictive, and limit the access of transplantation for many patients who would otherwise achieve good clinical outcomes. The liver transplant community has been making every effort to reach a goal of establishing more reliable selection criteria. This article addresses how the criteria have been extended, as well as the concept of pre-transplant down-staging to maximize the eligibility.

Abstract

Hepatocellular carcinoma (HCC) is the third highest cause of cancer-related mortality, and liver transplantation is the ideal treatment for this disease. The Milan criteria provided the opportunity for HCC patients to undergo LT with favorable outcomes and have been the international gold standard and benchmark. With the accumulation of data, however, the Milan criteria are not regarded as too restrictive. After the implementation of the Milan criteria, many extended criteria have been proposed, which increases the limitations regarding the morphological tumor burden, and incorporates the tumor’s biological behavior using surrogate markers. The paradigm for the patient selection for LT appears to be shifting from morphologic criteria to a combination of biologic, histologic, and morphologic criteria, and to the establishment of a model for predicting post-transplant recurrence and outcomes. This review article aims to characterize the various patient selection criteria for LT, with reference to several surrogate markers for the biological behavior of HCC (e.g., AFP, PIVKA-II, NLR, 18F-FDG PET/CT, liquid biopsy), and the response to locoregional therapy. Furthermore, the allocation rules in each country and the present evidence on the role of down-staging large tumors are addressed.

Prognostic role of selection criteria for liver transplantation in patients with hepatocellular carcinoma: a network meta-analysis

BACKGROUND

Patients with hepatocellular carcinoma (HCC) are selected for transplantation if they have a low tumour burden and low risk of recurrence. The morphometric Milan criteria have been the cornerstone for patient selection, but dynamic morphological and biological tumour characteristics surfaced as an encouraging tool to refine the selection of patients with HCC and to support the expansion of the Milan criteria. The outcomes of the most prevalent models that select patients with HCC for liver transplantation were analysed in this study, which aimed to identify the selection model that offered the best recurrence-free and overall survival after transplantation.

METHODS

Studies that compared Milan, University of California San Francisco (UCSF), up-to-seven (UPTS), alpha-fetoprotein (AFP), and MetroTicket 2.0 (MT2) models were included. One-year, 3-year, and 5-year recurrence-free and overall survival rates of patients selected for transplantation using different models were analysed.

RESULTS

A total of 60 850 adult patients with HCC selected for liver transplantation using Milan, UCSF, UPTS, AFP, or MT2 criteria were included. Patients selected for transplantation using the MT2 model had the highest 1-, 3-, and 5-year recurrence-free survival. In addition, patients selected for transplantation using MT2 criteria had the best 1- and 3-year overall survival, whereas patients selected for transplantation using the Milan criteria had the best 5-year overall survival rates.

CONCLUSION

The MT2 model offered the best post-transplant outcomes in patients with HCC, highlighting the importance of considering tumour morphology and biology when selecting patients with HCC for liver transplantation.

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.

Hepatocellular cancer selection systems and liver transplantation: from the tower of babel to an ideal comprehensive score

The Milan criteria (MC) remain the cornerstone for the selection of patients with hepatocellular cancer (HCC) to be listed for liver transplantation (LT). Recently, several expanded criteria have been proposed to increase the transplantability of HCC patients without compromising their (oncologic) outcome. This paper aims to systematically review the different reported HCC-LT selection systems looking thereby at their ability to increase the number of transplantable patients and the overall survival and oncological outcome. A systematic review of the literature covering the period 1993 (date of the first reported HCC-LT selection system)-2021 identified 59 different inclusion criteria of HCC for LT. Among the 59 studies reporting HCC-LT selection systems, 15 (28.3%) were exclusively based on morphological aspects of the tumor; 29 (54.7%) included biologic, seven (13.2%) radiological, and two (3.8%) only included pathological tumor features. Overall, 31% more patients could be transplanted when adhering to the new HCC-LT selection systems. Despite the increased number of LT, 5-year patient and disease-free survival rates were similar between MC-IN and MC-OUT/new HCC-LT-IN criteria. A careful extension of the inclusion criteria should allow many more patients to access a potentially curative LT without compromising their outcome. The development of a widely accepted "comprehensive" HCC-LT Score able to offer a fair chance of justified transplantation to more patients should become a priority within the liver transplant community. Further studies are needed to develop internationally accepted, expanded selection criteria for liver transplantation of HCC patients.

Liver transplantation in malignant disease

Liver transplantation for malignant disease has gained increasing attention as part of transplant oncology. Following the implementation of the Milan criteria, hepatocellular carcinoma (HCC) was the first generally accepted indication for transplantation in patients with cancer. Subsequently, more liberal criteria for HCC have been developed, and research on this topic is still ongoing. The evident success of liver transplantation for HCC has led to the attempt to extend its indication to other malignancies. Regarding perihilar cholangiocarcinoma, more and more evidence supports the use of liver transplantation, especially after neoadjuvant therapy. In addition, some data also show a benefit for selected patients with very early stage intrahepatic cholangiocarcinoma. Hepatic epithelioid hemangioendothelioma is a very rare but nonetheless established indication for liver transplantation in primary liver cancer. In contrast, patients with hepatic angiosarcoma are currently not considered to be optimal candidates. In secondary liver tumors, neuroendocrine cancer liver metastases are an accepted but comparability rare indication for liver transplantation. Recently, some evidence has been published supporting the use of liver transplantation even for colorectal liver metastases. This review summarizes the current evidence for liver transplantation for primary and secondary liver cancer.

Predicting survival after liver transplantation in patients with hepatocellular carcinoma using the LiTES-HCC score

BACKGROUND & AIMS

Liver transplant priority in the US and Europe follows the 'sickest-first' principle. However, for patients with hepatocellular carcinoma (HCC), priority is based on binary tumor criteria to expedite transplant for patients with 'acceptable' post-transplant outcomes. Newer risk scores developed to overcome limitations of these binary criteria are insufficient to be used for waitlist priority as they focus solely on HCC-related pre-transplant variables. We sought to develop a risk score to predict post-transplant survival for patients using HCC- and non-HCC-related variables.

METHODS

We performed a retrospective cohort study using national registry data on adult deceased-donor liver transplant (DDLT) recipients with HCC from 2/27/02-12/31/18. We fit Cox regression models focused on 5- and 10-year survival to estimate beta coefficients for a risk score using manual variable selection. We then calculated absolute predicted survival time and compared it to available risk scores.

RESULTS

Among 6,502 adult DDLT recipients with HCC, 11 variables were selected in the final model. The AUCs at 5- and 10-years were: 0.62, 95% CI 0.57-0.67 and 0.65, 95% CI 0.58-0.72, which was not statistically significantly different to the Metroticket and HALT-HCC scores. The LiTES-HCC score was able to discriminate patients based on post-transplant survival among those meeting Milan and UCSF criteria.

CONCLUSION

We developed and validated a risk score to predict post-transplant survival for patients with HCC. By including HCC- and non-HCC-related variables (e.g., age, chronic kidney disease), this score could allow transplant professionals to prioritize patients with HCC in terms of predicted survival. In the future, this score could be integrated into survival benefit-based models to lead to meaningful improvements in life-years at the population level.

LAY SUMMARY

We created a risk score to predict how long patients with liver cancer will live if they get a liver transplant. In the future, this could be used to decide which waitlisted patients should get the next transplant.

Impact of cytomegalovirus reactivation just before liver transplantation: A prospective cohort study

BACKGROUND

Cytomegalovirus (CMV) is the most common viral pathogen after liver transplantation (LT). Although reactivation of CMV infection is generally described in the context of immunosuppression, it has also been described in critically ill immunocompetent patients including cirrhotic patients.

AIM

To determine the incidence of reactivated CMV prior to LT.

METHODS

This was a prospective cohort study evaluating adult patients who underwent LT between 2014 and 2016. A plasma sample was obtained from all patients for CMV quantitative real-time PCR testing right before transplantation. Patients were followed for at least 1 year to assess the following outcomes: Incidence of CMV infection, organ rejection and overall mortality.

RESULTS

A total of 72 patients were enrolled. Four patients died before transplantation, thus 68 patients were followed up for a median of 44 mo (20-50 mo). In 23/72 patients (31.9%) CMV was reactivated before transplantation. Post-transplantation, 16/68 (23.5%) patients had CMV infection and that was significantly associated with the recipient being CMV negative and a CMV-positive donor. Pre-transplant CMV reactivation was not associated with overall mortality (log rank: 0.9).

CONCLUSION

This study shows that CMV infection is common in patients with chronic liver disease just before LT, but the clinical impact of this infection seems to be negligible.

A National Survey of Hepatocellular Carcinoma Surveillance Practices Following Liver Transplantation

Recurrence of hepatocellular carcinoma (HCC) is an important predictor of survival after liver transplantation (LT). Recent studies show that early diagnosis, aggressive treatment, and surveillance may improve outcomes after HCC recurrence. We sought to determine the current practices and policies regarding surveillance for HCC recurrence after LT.

Methods

We conducted a web-based national survey of adult liver transplant centers in the United States to capture center-specific details of HCC surveillance post-LT. Responses were analyzed to generate numerical and graphical summaries.

Results

Of 101 eligible adult liver transplant centers, 48 (48%) centers across the United States responded to the survey. Among the participating centers, 79% stratified transplant recipients for HCC recurrence risk, while 19% did not have any risk stratification protocol. Explant microvascular invasion (mVI) was the most common factor used in risk stratification. Use of pretransplant serum biomarkers such as alpha-fetoprotein (AFP) was variable, with only 48% of the participating centers reporting specific "cutoff" values. While a majority of centers (88%) reported having a routine imaging protocol for HCC recurrence surveillance, there was considerable heterogeneity in terms of frequency and duration of such surveillance. Of the centers that did risk stratify patients to identify those at higher risk of HCC recurrence, about 50% did not change their surveillance protocol.

Conclusions

Our study affirms significant variability in center practices, and our results reflect the need for high-quality studies to guide risk stratification and surveillance for HCC recurrence.

Using Hepatocellular Carcinoma Tumor Burden Score to Stratify Prognosis after Liver Transplantation

Liver transplantation (LT) remains a mainstay of treatment for hepatocellular carcinoma (HCC). Tumor factors such as size and number of tumors define eligibility for LT using the Milan criteria. The tumor burden score (TBS) incorporates both tumor number and size into a single continuous variable and has been used to differentiate prognosis among patients undergoing resection for HCC. The objective of the present study was to evaluate the ability of the TBS to predict overall and recurrence-free survival in patients undergoing LT for HCC. The Scientific Registry of Transplant Recipients (SRTR) was used to analyze all liver transplants for HCC, with initial tumor size data from 2004 to 2018. There were 12,486 patients in the study period. In the unadjusted analyses, patients with a high TBS had worse overall (p < 0.0001) and recurrence-free (p < 0.0001) survival. In the adjusted analyses, a high TBS was associated with a greater hazard ratio (HR) of death (HR = 1.21; 95%CI, [1.13-1.30]; p < 0.001) and recurrence (HR = 1.49; 95%CI [1.3-1.7]; p < 0.001). When we superimposed the TBS on the Milan criteria, we saw that a higher TBS was associated with a higher hazard of recurrence at values that were either all within (HR = 1.20; 95%CI, [1.04-1.37]; p = 0.011) or variably within (HR = 1.53; 95%CI, [1.16-2.01]; p = 0.002) the Milan criteria. In conclusion, the TBS is a promising tool in predicting outcomes in patients with HCC after LT.

Liver transplantation for hepatocellular carcinoma: impact of expansion criteria in a multicenter cohort study from a high waitlist mortality region

This study aimed to compare liver transplantation (LT) outcomes and evaluate the potential rise in numbers of LT candidates with hepatocellular carcinoma (HCC) of different allocation policies in a high waitlist mortality region. Three policies were applied in two Latin American cohorts (1085 HCC transplanted patients and 917 listed patients for HCC): (i) Milan criteria with expansion according to UCSF downstaging (UCSF-DS), (ii) the AFP score, and (iii) restrictive policy or Double Eligibility Criteria (DEC; within Milan + AFP score ≤2). Increase in HCC patient numbers was evaluated in an Argentinian prospective validation set (INCUCAI; NCT03775863). Expansion criteria in policy A showed that UCSF-DS [28.4% (CI 12.8-56.2)] or "all-comers" [32.9% (CI 11.9-71.3)] had higher 5-year recurrence rates compared to Milan, with 10.9% increase in HCC patients for LT. The policy B showed lower recurrence rates for AFP scores ≤2 points, even expanding beyond Milan criteria, with a 3.3% increase. Patients within DEC had lower 5-year recurrence rates compared with those beyond DEC [13.3% (CI 10.1-17.3) vs 24.2% (CI 17.4-33.1; P = 0.0006], without significant HCC expansion. In conclusion, although the application of a stricter policy may optimize the selection process, this restrictive policy may lead to ethical concerns in organ allocation (NCT03775863).

A 2020 update on liver transplant for hepatocellular carcinoma

INTRODUCTION

Hepatocellular carcinoma is the most frequent liver tumor and is associated with chronic liver disease in 90% of cases. In selected cases, liver transplantation represents an effective therapy with excellent overall survival.

AREA COVERED

Since the introduction of Milan criteria in 1996, numerous alternative selection systems to LT for HCC patients have been proposed. Debate remains about how best to select HCC patients for transplant and how to prioritize them on the waiting list.

EXPERT OPINION

The selection of the best scoring system to propose in the context of LT for HCC is far to be identified. In this review, we analyze and categorize the various selection systems, assessing their roles in the different decisional phases.

Risk assessment criteria in liver transplantation for hepatocellular carcinoma: proposal to improve transplant oncology

Liver transplantation for hepatocellular carcinoma has proved to be a highly effective cure if the right patient can be selected. Milan criteria has traditionally guided physicians toward appropriate liver allocation but changes in clinical practice, patient populations and recent developments in biomarkers are decreasing Milan criteria’s utility. At the same time, the literature has flooded with a diversity of new criteria that demonstrate strong predictive power and are better suited for current clinical practice. In this article, the utility of newly proposed criteria will be reviewed and important issues to improve future criteria will be addressed in hopes of opening a discussion on how key questions surrounding criteria for liver transplantation of hepatocellular carcinoma can be answered.

Essential updates 2018/2019: Liver transplantation

Among the recent topics in the field of liver transplantation (LT), one of the significant therapeutic breakthroughs is the introduction of direct-acting antiviral agents (DAAs) against hepatitis C virus (HCV) infection. With cure rates close to 100%, a better proportion of LT candidates and recipients can be cured of HCV infection by DAA therapies that are simple and well-tolerated. Other critical topics include the issue of indication of LT for patients with hepatocellular carcinoma, which has been continuously studied. Several expanded criteria beyond the Milan criteria with acceptable results have been recently reported. The role of donor-specific antibodies (DSAs) in intractable rejection is also an important matter that has been studied. Although long recognized as an important factor in antibody-mediated rejection and even graft survival in renal transplantation, the impact of DSAs on graft and patient survival in LT remains to be elucidated. Including the issues described above, this article focuses on recent advances in LT, management to avoid recurrence of primary diseases, optimization of immunosuppressive treatment, and extended donor criteria.

Role of the E3 Ubiquitin Ligase TRIM4 in Predicting the Prognosis of Hepatocellular Carcinoma

The E3 ubiquitin ligase TRIM4 has been reported to regulate the assembly of the antiviral signalling complex, induce mitochondrial aggregation and sensitize cells to H₂O₂-induced death. However, the relationship between TRIM4 and human malignancies, including hepatocellular carcinoma (HCC), is unclear. In this study, we detected the expression of TRIM4 in 134 pairs of HCC tissues and peritumoural tissues and investigated the association of TRIM4 expression with the prognosis of HCC. We found that the TRIM4 expression was much lower in HCC tissues than in peritumoural tissues and was significantly associated with vascular invasion, tumour capsule and Hong Kong Liver Cancer (HKLC) stage. Univariate and multivariate analyses revealed that the TRIM4 expression was an independent prognostic factor for overall survival (OS) and recurrence-free survival (RFS) in our HCC cohort. Patients with higher TRIM4 expression had a lower incidence of intrahepatic recurrence and a higher OS rate (p<0.001 and p<0.01, respectively). These results were further validated in another independent cohort of 200 HCC patients. In conclusion, the TRIM4 level in HCC tissues is an independent prognostic factor for HCC patients. Close clinical monitoring is recommended for patients with low TRIM4 expression.

Identification of an Upper Limit of Tumor Burden for Downstaging in Candidates with Hepatocellular Cancer Waiting for Liver Transplantation: A West-East Collaborative Effort

Since the introduction of Milan Criteria, all scoring models describing the prognosis of hepatocellular cancer (HCC) after liver transplantation (LT) have been exclusively based on characteristics available at surgery, therefore neglecting the intention-to-treat principles. This study aimed at developing an intention-to-treat model through a competing-risk analysis. Using data available at first referral, an upper limit of tumor burden for downstaging was identified beyond which successful LT becomes an unrealistic goal. Twelve centers in Europe, United States, and Asia (Brussels, Sapienza Rome, Padua, Columbia University New York, Innsbruck, Medanta-The Medicity Dehli, Hong Kong, Kyoto, Kaohsiung Taiwan, Mainz, Fukuoka, Shulan Hospital Hangzhou) created a Derivation (n = 2318) and a Validation Set (n = 773) of HCC patients listed for LT between January 2000–March 2017. In the Derivation Set, the competing-risk analysis identified two independent covariables predicting post-transplant HCC-related death: combined HCC number and diameter (SHR = 1.15; p < 0.001) and alpha-fetoprotein (AFP) (SHR = 1.80; p < 0.001). WE-DS Model showed good diagnostic performances at internal and external validation. The identified upper limit of tumor burden for downstaging was AFP ≤ 20 ng/mL and up-to-twelve as sum of HCC number and diameter; AFP = 21–200 and up-to-ten; AFP = 201–500 and up-to-seven; AFP = 501–1000 and up-to-five. The WE-DS Model proposed here, based on morphologic and biologic data obtained at first referral in a large international cohort of HCC patients listed for LT, allowed identifying an upper limit of tumor burden for downstaging beyond which successful LT, following downstaging, results in a futile transplantation.

Recent advances in liver transplantation for cancer: The future of transplant oncology

Liver transplantation is widely indicated as a curative treatment for selected patients with hepatocellular carcinoma. However, with recent therapeutic advances, as well as efforts to increase the donor pool, liver transplantation has been carefully expanded to patients with other primary or secondary malignancies in the liver. Cholangiocarcinoma, colorectal and neuroendocrine liver metastases, and hepatic epithelioid haemangioendothelioma are amongst the most relevant new indications. In this review we discuss the fundamental concepts of this ambitious undertaking, as well as the newest indications for liver transplantation, with a special focus on future perspectives within the recently established concept of transplant oncology.