Comparison of 3 Explant-Based Prognostic Models as Predictors of Hepatocellular Carcinoma Recurrence After Liver Transplantation: Analysis of Our Experience

Different Models to Predict the Risk of Recurrent Hepatocellular Carcinoma in the Setting of Liver Transplantation

Simple Summary

Liver transplantation is considered the first-choice curative therapy for hepatocellular carcinoma in the early phase of the disease, when surgical resection is not possible. Even when implementing restrictive criteria to select patients for liver transplantation, there is a risk of recurrence in the transplanted liver, influencing the long-term outcome and prognosis. As it is challenging to predict the individual risk of recurrence, there is a need for validated and predictive scoring systems to use to stratify patients before and/or after liver transplantation. Most of the proposed scorings include biological markers for tumour behavior, in addition to the number and size of tumoral nodules. In this review, we discuss different published models to assess the risk of recurrent hepatocellular carcinoma after transplantation. Our aim is to refine clinical decisions about prioritization and listing for liver transplantation, to better inform patients and provide an appropriate surveillance strategy to influence their prognosis.

Abstract

Liver transplantation is the preferred therapeutic option for non-resectable hepatocellular carcinoma in early-stage disease. Taking into account the limited number of donor organs, liver transplantation is restricted to candidates with long-term outcomes comparable to benign indications on the waiting list. Introducing the morphometric Milan criteria as the gold standard for transplant eligibility reduced the recurrence rate. Even with strict patient selection, there is a risk of recurrence of between 8 and 20% in the transplanted liver, and this is of even greater importance when using more expanded criteria and downstaging protocols. Currently, it remains challenging to predict the risk of recurrence and the related prognosis for individual patients. In this review, the recurrence-risk-assessment scores proposed in the literature are discussed. Currently there is no consensus on the optimal model or the implications of risk stratification in clinical practice. The most recent scorings include additional biological markers for tumour behavior, such as alfa-foetoprotein, and the response to locoregional therapies, in addition to the number and diameter of tumoral nodules. The refinement of the prediction of recurrence is important to better inform patients, guide decisions about prioritization and listing and implement individualized surveillance strategies. In the future, this might also provide indications for tailored immunosuppressive therapy or inclusion in trials for adjuvant treatment.

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.

Systematic review: risk prediction models for recurrence of hepatocellular carcinoma after liver transplantation

Recurrence of hepatocellular carcinoma (HCC) after liver transplantation (LT) is a significant clinical problem associated with poor surgical outcomes. This study aims to summarize the current evidence on risk prediction models of HCC recurrence after LT. PubMed and EMBASE were searched to May 25, 2019, for relevant articles. Studies originally designed to develop or validate a risk prediction model for HCC recurrence after LT were included. Two independent authors summarized the study characteristics and evaluated the risk of bias and applicability concerns in the included studies. From 26 included studies, 18 original risk prediction models were determined, but only five models were externally validated. The average number of predictors involved in the construction of risk models was three. The most frequently employed predictors were alpha-fetoprotein, tumor size, vascular invasion, tumor number, tumor differentiation, and neutrophil-lymphocyte ratio. Most studies showed good discriminatory performance (AUC >0.75). The overall quality of the included studies was generally low. Most of the original models lacked the highly recommended external and prospective validation in diverse populations. The AFP model was the well-validated preoperative risk model that can stratify patients into high- and low-risk groups.

Predictive Models of Hepatocellular Carcinoma Recurrence After Liver Transplantation

BACKGROUND

Liver transplantation (LT) is a curative treatment for patients with hepatocellular carcinoma who are not candidates for resection. Despite the generalized use of the Milan criteria and up-to-seven criteria, new markers have been proposed to predict recurrence after LT. Biomarkers such as neutrophil-lymphocyte ratio (NLR) and platelet-lymphocyte ratio (PLR), and scores such as the Model of Recurrence After Liver transplantation (MORAL) are used as predictors of post-LT recurrence.

OBJECTIVE

We aim to compare NLR, PLR, and MORAL score with Milan criteria and up-to-seven criteria.

METHODS

A descriptive study of 99 patients who underwent LT for hepatocellular carcinoma in our hospital between April 2010 and April 2016. The 5 prognostic models were applied to the patients to stratify them into risk groups. We used a Kaplan-Meier survival plot to measure recurrence-free survival in each model. Receiver operative curves were used to compare the models.

RESULTS

Three-year recurrence-free survival in MORAL was 91.1% for the low-risk group, 89.8% for the moderate-risk group, 60% for the high-risk group, and 75% for the very high-risk group (P = .003). The combined MORAL score was superior in predicting 1- and 3-year recurrence with the area under the curve 0.684 (95% confidence interval [CI]: 0.52-0.85) compared with Milan (0.536 [95% CI: 0.37-0.70]), up-to-seven (0.601 [95% CI: 0.43-0.77]), PLR (0.452 [95% CI: 0.30-0.61]), and NLR (0.542 [95% CI: 0.37-0.71]).

CONCLUSIONS

A model based only on pre-LT radiological signs leads to underdiagnosis of tumor load; therefore, the risk of recurrence must be recalculated after LT. The combined MORAL score was the best prognostic model of 1- and 3-year recurrence after LT in our study.