HEPATOCELLULAR CARCINOMA PATIENTS ARE ADVANTAGED IN THE CURRENT BRAZILIAN LIVER TRANSPLANT ALLOCATION SYSTEM. A COMPETING RISK ANALYSIS

Performance of eight predictive models for hepatocellular carcinoma recurrence after liver transplantation: A comparative study

INTRODUCTION AND OBJECTIVES

Liver transplantation is the optimal treatment for patients with early hepatocellular carcinoma and cirrhosis. However, hepatocellular carcinoma recurs in approximately 15 % of individuals. This study aimed to assess the efficacy of predictive models for hepatocellular carcinoma recurrence after liver transplantation.

PATIENTS AND METHODS

This retrospective study included 381 patients with HCC and evaluated the performance of the following models: R3-AFP score, alpha-fetoprotein (AFP) model, University of California, Los Angeles (UCLA) nomogram, Pre-Model of Recurrence after Liver Transplantation (MORAL), Post-MORAL, and Combo MORAL models, Risk Estimation of Tumor Recurrence (RETREAT) model and Platelet to Lymphocyte Ratio (PLR) model.

RESULTS

The R3-AFP score, UCLA nomogram, AFP model, RETREAT, Combo MORAL, and Post-MORAL models exhibited comparable AUROCs, ranging from 0.785 to 0.733. The AUROCs for the R3-AFP model and AFP model were superior to those of the Pre-MORAL and PLR models. The UCLA nomogram, RETREAT score, Combo MORAL model, and Post-MORAL model performed similarly to the first two models, but were only superior to the PLR model.

CONCLUSIONS

The R3-AFP model, UCLA nomogram, AFP model, RETREAT, Combo MORAL, and Post-MORAL models demonstrated a moderate predictive capacity for hepatocellular carcinoma recurrence following transplantation. No significant differences were observed among these models in their ability to predict recurrence.

INDICATION FOR LIVER TRANSPLANTATION DUE TO HEPATOCELLULAR CARCINOMA: ANALYSIS OF 1,706 PROCEDURES OVER THE PAST DECADE IN THE STATE OF PARANÁ

BACKGROUND

Patients listed for liver transplantation and hepatocellular carcinoma are considered priority on the waiting list, and this could overly favor them.

AIM

This study aimed to evaluate the impact of this prioritization.

METHODS

We analyzed the liver transplants performed in adults from 2011 to 2020 and divided into three groups: adjusted Model of End-Stage Liver Disease (MELD) score for hepatocellular carcinoma, other adjusted Model of End-Stage Liver Disease situations, and no adjusted Model of End-Stage Liver Disease.

RESULTS

A total of 1,706 patients were included in the study, of which 70.2% were male. Alcoholism was the main etiology of cirrhosis (29.6%). Of the total, 305 patients were with hepatocellular carcinoma, 86 with other adjusted Model of End-Stage Liver Disease situations, and 1,315 with no adjusted Model of End-Stage Liver Disease. Patients with hepatocellular carcinoma were older (58.9 vs. 53.5 years). The predominant etiology of cirrhosis was viral hepatitis (60%). The findings showed that group with adjusted Model of End-Stage Liver Disease had lower physiological Model of End-Stage Liver Disease (10.9), higher adjusted Model of End-Stage Liver Disease (22.6), and longer waiting list time (131 vs. 110 days), as compared to the group with no adjusted Model of End-Stage Liver Disease. The total number of transplants and the proportion of patients transplanted for hepatocellular carcinoma increased from 2011 to 2020. There was a reduction in the proportion of patients with hepatocellular carcinoma and adjusted Model of End-Stage Liver Disease of 20 and there was an increase on waiting list time in this group. There was an increase in the proportion of those with adjusted Model of End-Stage Liver Disease of 24 and 29, but the waiting list time remained stable.

CONCLUSION

Over the past decade, prioritization of hepatocellular carcinoma resulted in an increased proportion of transplanted patients in relation to those with no priority. It also increased waiting list time, requiring higher adjusted Model of End-Stage Liver Disease to transplant an organ.

Artificial intelligence and human liver allocation: Potential benefits and ethical implications

Since its implementation almost two decades ago, the urgency allocation policy has improved the survival of patients on the waiting list for liver transplantation worldwide. The Model for End-Stage Liver Disease score is widely used to predict waiting list mortality. Due to some limitations related to its use, there is an active investigation to develop other prognostic scores. Liver allocation (LA) entails complex decision-making, and grafts are occasionally not directed to the recipients who are more likely to survive. Prognostic scores have, thus far, failed to predict post-operatory survival. Furthermore, the increasing use of marginal donors is associated with worse outcomes. Adequate donor-recipient pairing could help avoid retransplantation or futile procedures and reduce postoperative complications, mortality, hospitalization time, and costs. Artificial intelligence has applications in several medical fields. Machine learning algorithms (MLAs) use large amounts of data to detect unforeseen patterns and complex interactions between variables. Artificial neural networks and decision trees were the most common forms of MLA tested on LA. Some researchers have shown them to be superior for predicting waiting list mortality and graft failure than conventional statistical methods. These promising techniques are increasingly being considered for implementation.

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).

MELD EXCEPTION POINTS PROVIDE AN ENOURMOUS ADVANTAGE FOR RECEIVING A LIVER TRANSPLANT IN BRAZIL

BACKGROUND

Current policy for listing to liver transplant (LT) may place cirrhotic patients without MELD exception points (CIR) in a disadvantageous position if compared to patients enlisted with appealed MELD scores - patients with hepatocellular carcinoma (HCC) or special conditions other than hepatocellular carcinoma (SPE). Transplant rates, delisting, and waitlist mortality of CIR, HCC, and SPE candidates were compared.

OBJECTIVE

The aim of this study is to counterweight the listing rate and speed of listing of HCC, SPE, and CIR patients. To the best of our knowledge, this is the first study comparing the outcomes of patients enlisted for SPE to those of HCC and CIR. In several countries worldwide, SPE patients also receive appealed MELD scores in a similar way of HCC patients.

METHODS

Two cohorts of patients listed for LT in a single institution were evaluated. The first cohort (C1, n=180) included all patients enlisted on August 1st, 2008, and all additional patients listed from this date until July 31st, 2009. The second cohort (C2, n=109) included all patients present on the LT list on October 1st, 2012, and all additional patients listed from this date until May 2014.

RESULTS

In both cohorts, HCC patients had a higher chance of receiving a LT than CIR patients (C1HR =2.05, 95%CI=1.54-2.72, P<0.0001; C2HR =3.17, 95%CI =1.83-5.52, P<0.0001). For C1, 1-year waiting list mortality was 21.6% (30.0% for CIR vs 9.5% for HCC vs 7.1% for SPE) (P<0.001). For C2, 1-year waiting list mortality was 13.3% (25.7% for CIR, 8.3% for HCC, and 4.0% for SPE) (P<0.001). Post-transplant survival was similar among the three groups.

CONCLUSION

Compared to CIR, SPE and HCC patients had lower wait list mortality. CIR patients had the highest waitlist mortality and the lowest odd of LT. Current LT allocation system does not allow equitable organ allocation.