Estimation of the harm to the waiting list as a crucial factor in the selection of patients with hepatocellular carcinoma for liver transplantation

Liver Transplantation for T2 Hepatocellular Carcinoma during the COVID-19 Pandemic: A Novel Model Balancing Individual Benefit against Healthcare Resources

Simple Summary

Using Italian national data from more than 8000 patients, we proposed a novel model calculating the net benefit of liver transplantation (individual benefit minus harm to others on the waiting list) in T2 hepatocellular carcinoma (HCC) patients in different scenarios of transplant activity reduction. Our results show that the transplant net benefit is closely related to the decrease in the number of organs, but it is also higher in T2 HCC patients than in non-HCC patients with the same model for end-stage liver disease (MELD) scores. Our model supports liver transplantation for T2 HCC with the highest net benefit also during crises such as COVID-19.

Abstract

The COVID-19 pandemic caused temporary drops in the supply of organs for transplantation, leading to renewed debate about whether T2 hepatocellular carcinoma (HCC) patients should receive priority during these times. The aim of this study was to provide a quantitative model to aid decision-making in liver transplantation for T2 HCC. We proposed a novel ethical framework where the individual transplant benefit for a T2 HCC patient should outweigh the harm to others on the waiting list, determining a “net benefit”, to define appropriate organ allocation. This ethical framework was then translated into a quantitative Markov model including Italian averages for waiting list characteristics, donor resources, mortality, and transplant rates obtained from a national prospective database (n = 8567 patients). The net benefit of transplantation in a T2 HCC patient in a usual situation varied from 0 life months with a model for end-stage liver disease (MELD) score of 15, to 34 life months with a MELD score of 40, while it progressively decreased with acute organ shortage during a pandemic (i.e., with a 50% decrease in organs, the net benefit varied from 0 life months with MELD 30, to 12 life months with MELD 40). Our study supports the continuation of transplantation for T2 HCC patients during crises such as COVID-19; however, the focus needs to be on those T2 HCC patients with the highest net survival benefit.

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.

Transplantation for hepatocellular cancer: pushing to the limits?

Milan criteria (MC) represents the cornerstone in the selection of patients with hepatocellular cancer (HCC) waiting for liver transplantation (LT). MC represent the precursor of the scores based on the idea of "utility": in other terms, the scoring systems typically used in the field of LT oncology present the exclusive aim of selecting the cases with the best post-LT outcomes. However, some other scores have been proposed specifically investigating the risk of death or tumour progression during the waiting list. In this case, the selection process is connected with the idea of "priority": patients at higher risk for drop-out (DO) should be selected, prioritising them or, conversely, deciding to de-list them due to the high risk of post-LT futile transplant. Lastly, models based on the concept of "benefit", namely the balancing between priority and utility, have been recently created. The present review aims to examine these three different types of scoring systems, trying to underline their pro and cons in the allocation process of HCC patients.

Expansion of the hepatocellular carcinoma Milan criteria in liver transplantation: Future directions

Milan criteria are currently the benchmark related to liver transplantation (LT) for hepatocellular carcinoma. However, several groups have proposed different expanded criteria with acceptable results. In this article, we review the current status of LT beyond the Milan criteria in three different scenarios-expanded criteria with cadaveric LT, downstaging to Milan criteria before LT, and expansion in the context of adult living donor LT. The review focuses on three main questions: what would the impact of the expansion beyond Milan criteria be on the patients on the waiting list; whether the dichotomous criteria (yes/no) currently used are appropriate for LT or continuous survival estimations, such as the one of “Metroticket” and whether it should enter into the clinical practice; and, whether the use of living donor LT in the context of expansion beyond Milan criteria is justified.

Intention-to-treat survival benefit of liver transplantation in patients with hepatocellular cancer

The debate about the best approach to select patients with hepatocellular cancer (HCC) waiting for liver transplantation (LT) is still ongoing. This study aims to identify the best variables allowing to discriminate between "high-" and "low-benefit" patients. To do so, the concept of intention-to-treat (ITT) survival benefit of LT has been created. Data of 2,103 adult HCC patients consecutively enlisted during the period 1987-2015 were analyzed. Three rigorous statistical steps were used in order to create the ITT survival benefit of LT: the development of an ITT LT and a non-LT survival model, and the individual prediction of the ITT survival benefit of LT defined as the difference between the median ITT survival with (based on the first model) and without LT (based on the second model) calculated for each enrolled patient. Four variables (Model for End-Stage Liver Disease, alpha-fetoprotein, Milan-Criteria status, and radiological response) displayed a high effect in terms of delta benefit. According to these risk factors, four benefit groups were identified. Patients with three to four factors ("no-benefit group"; n = 405 of 2,103; 19.2%) had no benefit of LT compared to alternative treatments. Conversely, patients without any risk factor ("large-benefit group"; n = 108; 5.1%) yielded the highest benefit from LT reaching 60 months.

CONCLUSION

The ITT transplant survival benefit presented here allows physicians to better select HCC patients waiting for LT. The obtained stratification may lead to an improved and more equitable method of organ allocation. Patients without benefit should be de-listed, whereas patients with large benefit ratio should be prioritized for LT. (Hepatology 2017;66:1910-1919).

Split liver transplantation: Papering over the cracks of the organ shortage

Splitting livers allows two people (usually an adult and a child) to receive a liver transplant from one donated adult liver, but the risks to the adult recipient are greater than if they had received the equivalent whole liver. It has been suggested, therefore, that splitting livers harms adult recipients. Without liver splitting, however, there would be few livers available for children, and paediatric waiting time and waiting list mortality would significantly increase. In this paper, we argue that although splitting livers makes adults worse off, this should be considered sub-optimal benefit rather than harm. We explore justifications for sub-optimally benefitting adults in this way and consider alternatives to the current approach. We argue that splitting livers masks the more fundamental problem of low paediatric donation rates and that increasing the number of paediatric donations would improve the situation for both adult and paediatric liver patients.

Simulation modeling of the impact of proposed new simultaneous liver and kidney transplantation policies

BACKGROUND

Increasing use of kidney grafts for simultaneous liver and kidney (SLK) transplants is causing concern about the most effective utilization of scarce kidney graft resources. This study evaluated the impact of implementing the proposed United Network for Organ Sharing SLK transplant policy on outcomes for end-stage liver disease (ESLD) and end-stage renal disease (ESRD) patients awaiting transplant.

METHODS

A Markov model was constructed to simulate a hypothetical cohort of ESLD patients over a 30-year time horizon starting from age 50. The model applies the different criteria being considered in the United Network for Organ Sharing policy and tallies outcomes, including numbers of procedures and life years after liver transplant alone (LTA) or SLK transplant.

RESULTS

When 1-week pretransplant dialysis duration is required, the numbers of SLK transplants and LTAs would be 648 and 9,065, respectively. If the pretransplant dialysis duration is extended to 12 weeks, there would be 240 SLK transplants and 9,426 LTAs. This change results in a decrease of 6,483 life years among SLK transplant recipients and an increase of 4,971 life years among LTA recipients. However, by increasing the dialysis duration to 12 weeks from 1 week, 408 kidney grafts would be released to the kidney waitlist because of the decline in SLK transplants; this yields 796 additional life years gained among ESRD patients.

CONCLUSION

Implementation of the proposed SLK transplant policy could restore access to kidney transplants for patients with ESRD albeit at the detriment of patients with ESLD and renal impairment.

Standing the test of time: outcomes of a decade of prioritizing patients with hepatocellular carcinoma, results of the UNOS natural geographic experiment

Priority is given to patients with hepatocellular carcinoma (HCC) to receive liver transplants, potentially causing significant regional disparities in organ access and possibly outcomes in this population. Our aim was to assess these disparities by comparing outcomes in long waiting time regions (LWTR, regions 5 and 9) and short waiting time regions (SWTR regions 3 and 10) by analyzing the United Network for Organ Sharing (UNOS) database. We analyzed 6,160 HCC patients who received exception points in regions 3, 5, 9, and 10 from 2002 to 2012. Data from regions 5 and 9 were combined and compared to data from regions 3 and 10. Survival was studied in three patient cohorts: an intent-to-treat cohort, a posttransplant cohort, and a cohort examining overall survival in transplanted patients only (survival from listing to last posttransplant follow-up). Multivariate analysis and log-rank testing were used to analyze the data. Median time on the list in the LWTR was 7.6 months compared to 1.6 months for SWTR, with a significantly higher incidence of death on the waiting list in LWTR than in SWTR (8.4% versus 1.6%, P < 0.0001). Patients in the LWTR were more likely to receive loco-regional therapy, to have T3 tumors at listing, and to receive expanded-criteria donor (ECD) or donation after cardiac death (DCD) grafts than patients in the SWTR (P < 0.0001 for all). Survival was significantly better in the LWTR compared to the SWTR in all three cohorts (P < 0.0001 for all three survival points). Being listed/transplanted in an SWTR was an independent predictor of poor patient survival on multivariate analysis (P < 0.0001, hazard ratio = 1.545, 95% confidence interval 1.375-1.736).

CONCLUSION

This study provides evidence that expediting patients with HCC to transplant at too fast a rate may adversely affect patient outcomes.

Current challenges in liver transplantation for hepatocellular carcinoma

Liver transplantation (LT) is the best option of cure for hepatocellular carcinoma (HCC). Notwithstanding several alternatives, Milan Criteria remain the cornerstone for patient selection. Currently, expanded criteria patients are unsuitable for LT without taking downstaging approaches and response to therapies into consideration. Relative weight of HCC as indication to LT is increasing and that generates competition with MELD-described non-cancer indications. Allocation policies should be adjusted accordingly, considering principles of urgency and utility in the management of the waiting list and including transplant benefit to craft equitable criteria to deal with the limited resource of donated grafts. Maximization of cost-effectiveness of LT in HCC can be also pursued through changes in immunosuppression policies and multimodal management of post-transplant recurrences. This review is focused on those constantly mutating challenges that have to be faced by anyone dealing with the management of HCC in the context of liver transplantation.

Surveillance for early diagnosis of hepatocellular carcinoma: How best to do it?

Surveillance for hepatocellular carcinoma (HCC) is considered a standard of care for patients with chronic liver disease who are at risk of developing this malignancy. Several studies have shown that surveillance can improve the prognosis of patients diagnosed with HCC through an increased likelihood of application of curative or effective treatments. Repetition of liver ultrasonography (US) every 6 mo is the recommended surveillance program to detect early HCCs, and a positive US has to entrain a well-defined recall policy based on contrast-enhanced, dynamic radiological imaging or biopsy for the diagnosis of HCC. Although HCC fulfills the accepted criteria regarding cost-effective cancer screening and surveillance, the implementation of surveillance in clinical practice is defective and this has a negative impact on the cost-effectiveness of the procedure. Education of both physicians and patients is of paramount importance in order to improve the surveillance application and its benefits in patients at risk of HCC. The promotion of specific educational programs for practitioners, clinicians and patients is instrumental in order to expand the correct use of surveillance in clinical practice and eventually improve HCC prognosis.

"Metroticket" predictor for assessing liver transplantation to treat hepatocellular carcinoma: a single-center analysis in mainland China

AIM

To validate the "Metroticket" predictor using a large cohort of liver transplantation (LT) patients with hepatocellular carcinoma (HCC) in China.

METHODS

In total, 230 cases of LT for HCC treatment at our center, from July 2000 to August 2008, were included in the present study. The predicted 1-, 3- and 5-year post-LT survival rates were calculated using the Metroticket model (http://89.96.76.14/metroticket/calculator/). The predicted and observed long-term survival rates were then compared and analyzed.

RESULTS

The predicted survival rates for all 230 cases, as calculated by the Metroticket model, were 64.7% and 56.2% at 3 and 5 years, respectively, and the observed survival rates for these patients were 71.3% and 57.8%, respectively. For the 23 cases with macrovascular invasion, the predicted 5-year survival rate was 43.5%, whereas the observed 5-year survival rate was only 8.7%. For the 42 cases with microvascular invasion but an absence of macrovascular invasion, the predicted 5-year survival rate was 44.9%, and the observed 5-year survival rate was 50%. For the remaining 165 patients without any vascular invasion, the predicted 5-year survival rate was 65.8%, and the observed 5-year survival rate was 66.7%.

CONCLUSION

The Metroticket model can be used to accurately predict survival in HCC-related LT cases with an absence of macrovascular invasion.

Living donor liver transplantation for hepatocellular carcinoma

Liver transplantation (LT) may be the best curative treatment that offers a chance of cure for the tumor and the underlying cirrhosis by complete extirpation of both. In Asia, where the supply of cadaveric grafts remains scarce and the incidence of HCC combined with chronic hepatitis B virus (HBV)- and hepatitis C virus (HCV)-related liver disease is high, adult living donor liver transplantation (LDLT) has been settled upon as a practical alternative to deceased-donor liver transplantation (DDLT). Even in Western countries, where adequate access to DDLT is feasible for HCC patients satisfying the Milan criteria, the necessity for LDLT is well established in particular for more advanced HCC patients who are disadvantaged by current allocation algorithms for grafts from deceased donors due to organ shortage, increasing waiting lists, and the expectation that many patients listed for LT will die while awaiting a suitable organ. In the field of LDLT in Asia, numerous technical innovations were achieved to secure donor safety, as well as to ensure patient survival. The experience with LDLT for HCC has been progressively increasing in many Asian countries to date. Although there are questions regarding the higher recurrence of HCC after LDLT than after DDLT, the application of the Milan and UCSF criteria to LDLT in high-volume multicenter cohorts from Japan and Korea has resulted in patient survival outcomes very similar to those following DDLT. Recently, inclusion of biologic tumor markers such as alpha fetoprotein (AFP), protein induced by vitamin K antagonist II (PIVKA II), and positive positron emission tomography (PET) in addition to parameters of tumor morphology might be the key to establishing the best criteria for LDLT for HCC. As pretransplant treatments, most LDLT centers in Asia cannot adopt the strategy of bridging therapy under scarcity of cadaveric organ donation but have to use those multi-modality treatments as a salvage intending for primary curative treatment or a downstaging therapy before LDLT. After LDLT, basically there is no difference in the management strategy for HCC recurrence between DDLD and LDLT.

Systematic review: the role of liver transplantation in the management of hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is a major cause of morbidity and mortality worldwide. Liver transplantation offers a potential cure for this otherwise devastating disease. The selection of the most appropriate candidates is paramount in an era of graft shortage.

AIM

To review systematically the role of liver transplantation in the management of HCC in current clinical practice.

METHODS

An electronic literature search using PUBMED (1980-2010) was performed. Search terms included HCC, hepatoma, liver cancer, and liver transplantation.

RESULTS

Liver transplantation is a highly successful treatment for HCC, in patients within Milan criteria (MC), defined as a solitary tumour ≤50 mm in diameter or ≤3 tumours ≤30 mm in diameter in the absence of extra-hepatic or vascular spread. Other eligibility criteria for liver transplantation are also used in clinical practice, such as the University of California, San Francisco criteria, with outcomes comparable to MC. Loco-regional therapies have a role in the bridging treatment of HCC by minimising wait-list drop-out secondary to tumour progression. Beyond MC, encouraging results have been demonstrated for patients with down-staged tumours. Post-liver transplantation, there is no evidence to support a specific immunosuppressive regimen. In the context of an insufficient cadaveric donor pool to meet demand, the role of adult living donation may be increasingly important.

CONCLUSIONS

Liver transplantation offers a curative therapy for selected patients with HCC. The optimisation of eligibility criteria is paramount to ensure that maximum benefit is accrued. Although wait-list therapies have been incorporated into clinical practice, additional high quality data are required to support this strategy.

Liver Transplantation for HCC: A Review

Hepatocellular carcinoma (HCC) often occurs in patients with chronic liver disease or cirrhosis. Liver transplantation for hepatocellular carcinoma has the potential to eliminate both the tumor as well as the underlying cirrhosis and is the ideal treatment for HCC in cirrhotic liver as well as massive HCC in noncirrhotic liver. Limitations in organ availability, necessitate stringent selection of patients who would likely to derive most benefit. Selection criteria have considered tumor size, number, volume as well as biological features. The Milan criteria set the benchmark for tumors that would benefit from liver transplantation but were found to be excessively restrictive. Modest expansion in criteria has also been shown to be associated with equivalent survival. Microvascular invasion is the single most important adverse prognostic factor for survival. Living donor liver transplantation has expanded donor options and has the advantage of lower waiting period and not impacting the non-HCC waiting list. Acceptable outcomes have been obtained with living donor liver transplantation for larger and more numerous tumors in the absence of microvascular invasion. Downstaging of tumors to prevent progression while waiting for an organ or for reduction in size to allow enrolment for transplantation has met with variable success.