HCC patients suffer less from geographic differences in organ availability

T2 Hepatocellular Carcinoma Exception Policies That Prolong Waiting Time Improve the Use of Evidence-based Treatment Practices

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Background.

A United Network for Organ Sharing policy change in 2015 created a 6-mo delay in the receipt of T2 hepatocellular carcinoma exception points. It was hypothesized that the policy changed locoregional therapy (LRT) practices and explant findings because of longer expected waiting time.

Methods.

Patients transplanted with a first T2 hepatocellular carcinoma exception application between January 1, 2010 and December 31, 2014 (prepolicy; N = 6562), and those between August 10, 2015 and December 2, 2019 (postpolicy; N = 2345), were descriptively compared using data from United Network for Organ Sharing.

Results.

Median time from first application to transplantation was more homogenous across the US postpolicy, due to greater absolute increases in Regions 3, 6, 10, and 11 (>120 d). During waitlisting, postpolicy candidates received more LRT overall (P < 0.001), with more notable increases in previously short-wait regions. Postpolicy explants were overall more likely to have ≥1 tumor with complete necrosis (23.9 versus 18.4%; P < 0.001) and less likely have ≥1 tumor with no necrosis (32.6% versus 38.5%; P < 0.001). Significant geographic variability in explant treatment response was observed prepolicy with recipients in previously short-wait regions having more frequent tumor viability at transplant. Postpolicy, there were no differences in the prevalence of recipients with ≥1 tumor with 100% or 0% necrosis across regions (P = 0.9 and 0.2, respectively).

Conclusions.

The 2015 T2 exception policy has led to reduced geographic variability in the use of pretransplant LRT and in less frequent tumor viability on explant for recipients in previously short-waiting times.

The rise and fall of the model for end-stage liver disease score and the need for an optimized machine learning approach for liver allocation

PURPOSE OF REVIEW

The Model for End-Stage Liver Disease (MELD) has been used to rank liver transplant candidates since 2002, and at the time bringing much needed objectivity to the liver allocation process. However, and despite numerous revisions to the MELD score, current liver allocation still does not allow for equitable access to all waitlisted liver candidates.

RECENT FINDINGS

An optimized prediction of mortality (OPOM) was developed utilizing novel machine-learning optimal classification tree models trained to predict a liver candidate's 3-month waitlist mortality or removal. When compared to MELD and MELD-Na, OPOM more accurately and objectively prioritized candidates for liver transplantation based on disease severity. In simulation analysis, OPOM allowed for more equitable allocation of livers with a resultant significant number of additional lives saved every year when compared with MELD-based allocation.

SUMMARY

Machine learning technology holds the potential to help guide transplant clinical practice, and thus potentially guide national organ allocation policy.

Disparities in the treatment of hepatocellular carcinoma based on geographical region are decreasing

BACKGROUND AND AIM

Geographic differences have existed in the management of hepatocellular carcinoma (HCC), and efforts to reduce regional disparities have been initiated. The aim of this study is to use the Nationwide Inpatient Sample to determine if regional disparities in the treatment of HCC continue to exist.

METHOD

A retrospective database analysis using the Nationwide Inpatient Sample was performed that included patients with a primary diagnosis of HCC. Logistic regression models were utilized to determine geographic disparities in liver decompensation, treatment, inpatient mortality, and metastatic disease.

RESULTS

This study's locational reach of 62 604 patients included 22 769 patients from the South (36%), 14 554 in the Northeast (23%), 14 041 in the West (22%), and 11 240 in the Midwest (18%). Patients who received treatment in the West were more likely to have inpatient mortality (OR 1.28, 95% CI 1.03, 1.53) than patients who received treatment in the Midwest. No significant differences were observed between rates of resection, ablation, and transarterial chemoembolization when comparing by region. Rates of liver transplantation were lower in the West compared with the Midwest (OR 0.51, 95% CI 0.29, 0.87). There was no significant difference between other regions.

CONCLUSION

Geographic disparities in the treatment of HCC are improving.

Proposal of a novel MELD exception point system for hepatocellular carcinoma based on tumor characteristics and dynamics

BACKGROUND & AIMS

Patients listed with exception points for hepatocellular carcinoma (HCC) have been more likely to be transplanted than those listed for chronic liver failure (LF) based on the model for end-stage liver disease (MELD) score. The aim of this study was to determine outcomes in the 5-year experience of a scoring system designed to reflect heterogeneity of tumor load of patients listed for HCC.

METHODS

A novel MELD exception point system based on size and number of HCC was implemented in July 2009. This system allows stratification of patients based on risk of dropping out from the waiting list according to Milan criteria. LF patients were listed according to biological MELD sodium score; HCC patients were reassigned points every three months upon repeat imaging.

RESULTS

Among 624 patients listed for liver transplant (LT), 505 were eligible. 94 (18.6%) were assigned MELD HCC points. Only 24.7% required changes in allocated points over time. Transplantation rates (HCC 83% vs. LF 73%, p=0.04) and waiting time in days (HCC 258 vs. LF 325; p=0.07) were similar. The method of competing risk analysis revealed that HCC patients were more likely to be transplanted than LF during the 5-year period preceding implementation, whereas transplant rates became equivalent for HCC and non-HCC in 2009-2014. One- and two-year survivals were similar between the two groups.

CONCLUSIONS

Our study demonstrates that a novel MELD point system for HCC, taking into account dynamics in tumor size and number, allows for equitable liver allocation without compromising graft and patient survival.

LAY SUMMARY

It has historically been difficult to achieve equitable liver allocation for liver cancer and chronic liver failure with the allocation systems currently in place in many countries worldwide. We designed a new system to help improve access to organs for liver failure patients in Québec, Canada. Our 5-year experience demonstrates that this unique system renders access to transplant similar for both liver cancer and liver failure indications.

First-Degree Living-Related Donor Liver Transplantation in Autoimmune Liver Diseases

Liver transplantation (LT) is the treatment of choice for end-stage autoimmune liver diseases. However, the underlying disease may recur in the graft in some 20% of cases. The aim of this study is to determine whether LT using living donor grafts from first-degree relatives results in higher rates of recurrence than grafts from more distant/unrelated donors. Two hundred sixty-three patients, who underwent a first LT in the Toronto liver transplant program between January 2000 and March 2015 for autoimmune liver diseases, and had at least 6 months of post-LT follow-up, were included in this study. Of these, 72 (27%) received a graft from a first-degree living-related donor, 56 (21%) from a distant/unrelated living donor, and 135 (51%) from a deceased donor for primary sclerosing cholangitis (PSC) (n = 138, 52%), primary biliary cholangitis (PBC) (n = 69, 26%), autoimmune hepatitis (AIH) (n = 44, 17%), and overlap syndromes (n = 12, 5%). Recurrence occurred in 52 (20%) patients. Recurrence rates for each autoimmune liver disease were not significantly different after first-degree living-related, living-unrelated, or deceased-donor LT. Similarly, time to recurrence, recurrence-related graft failure, graft survival, and patient survival were not significantly different between groups. In conclusion, first-degree living-related donor LT for PSC, PBC, or AIH is not associated with an increased risk of disease recurrence.

Patient-reported outcomes in liver transplant recipients with hepatocellular carcinoma

BACKGROUND

The effect of awarding MELD exception points for hepatocellular carcinoma (HCC) on patient-reported outcomes (PROs) is unknown. We evaluated the physical and mental health-related quality of life (HRQOL) and symptoms of anxiety and depression in liver transplant recipients with HCC compared to patients without HCC.

METHODS

The single-center sample measured PROs before and after transplant, which included 1521 multisurvey measurement points among 502 adults (67% male, 28% HCC, follow-up time: <1-131 months). Data were analyzed using multivariable mixed-effects models.

RESULTS

Longitudinal PRO values did not differ between persons who received HCC exception points and those who did not have HCC. Patients with HCC who did not receive exception points had reduced physical HRQOL (P=.016), a late decline in mental HRQOL, and delayed reduction in anxiety (time-by-outcome interaction P<.050) compared to patients with HCC who received exception points.

CONCLUSION

Transplant recipients who received HCC exception points had PROs that were comparable to those of patients without HCC, and reported better physical HRQOL and reduced symptoms of anxiety compared to patients with HCC who did not receive exception points. These analyses demonstrate the impact of HCC exception points on PROs, and may help inform policy regarding HCC exception point allocation.

Management of Hepatocellular Carcinoma: Current Status and Future Directions

Hepatocellular carcinoma (HCC) is the second most common cause of cancer death worldwide. This cancer commonly arises against a background of chronic liver disease. As a result, a patient with HCC requires multidisciplinary care. Treatment options vary widely based on tumor burden and metastases. The most widely utilized staging system is the Barcelona Clinic Liver Cancer staging system, which recommends treatments based on tumor size and the underlying liver disease and functional status of the patient. Treatment options range from surgical resection or transplantation to locoregional therapies with modalities such as radiofrequency ablation and transarterial chemoembolization to systemic chemotherapies. Future care involves the development of combination therapies that afford the best tumor response, further clarification of the patients best suited for therapies and the development of new oral chemotherapeutic agents.

Patterns and Outcomes Associated with Patient Migration for Liver Transplantation in the United States

Background

Traveling to seek specialized care such as liver transplantation (LT) is a reality in the United States. Patient migration has been attributed to organ availability. The aims of this study were to delineate patterns of patient migration and outcomes after LT.

Study Design

All deceased donor LT between 2008–2013 were extracted from UNOS data. Migrated patients were defined as those patients who underwent LT at a center in a different UNOS region from the region in which they resided and traveled a distance > 100 miles.

Results

Migrated patients comprised 8.2% of 28,700 LT performed. Efflux and influx of patients were observed in all 11 UNOS regions. Regions 1, 5, 6, and 9 had a net efflux, while regions 2, 3, 4, 7, 10, and 11 had a net influx of patients. After multivariate adjustment for donor and recipient factors, graft (p = 0.68) and patient survival (p = 0.52) were similar between migrated and non-migrated patients.

Conclusion

A significant number of patients migrated in patterns that could not be explained alone by regional variations in MELD score and wait time. Migration may be a complex interplay of factors including referral patterns, specialized services at centers of excellence and patient preference.

Comparison of Liver Transplant-Related Survival Benefit in Patients With Versus Without Hepatocellular Carcinoma in the United States

BACKGROUND & AIMS

Patients with T2 hepatocellular carcinoma (HCC) can obtain an exception that allows them to undergo liver transplantation with much lower actual Model for End-Stage Liver Disease (MELD) scores than patients without HCC. We compared patients who received liver transplants, with and without HCC, with regard to transplantation-related survival benefit.

METHODS

We modeled the post-transplantation survival of adult, first-time liver transplant recipients with HCC (n = 9135) or without (n = 25,890) from 2002 through 2013 using Cox proportional hazards regression. We modeled waitlist survival of patients listed for transplantation with HCC (n = 15,605) or without (n = 85,229) using competing risks analysis and combined outcomes of death or liver failure (defined as MELD score ≥30). We used these survival models to calculate monthly transition probabilities and 5-year life expectancies. Survival benefit was calculated as the difference between post-transplantation and waitlist life expectancy.

RESULTS

The 5-year survival benefit increased with actual MELD score for patients with and without HCC, ranging from just a few months in patients with low MELD scores (ie, 6-8) to 4 years in patients with the highest MELD scores (ie, 36-40). The survival benefit of patients with HCC was similar to that of patients without HCC who had the same actual MELD score, irrespective of tumor burden or serum level of α-fetoprotein. However, because patients with HCC received liver transplants when they had a lower mean MELD score (13.3 ± 6.2) than patients without HCC (21.8 ± 8.0), a much lower mean 5-year survival benefit was achieved by providing liver transplants to patients with HCC (0.12 years/patient) than patients without HCC (1.47 years/patient).

CONCLUSIONS

The HCC MELD exception policy has unintentionally resulted in a large reduction in transplantation-related survival benefit.

Impact of geography on organ allocation: Beyond the distance to the transplantation center

AIM

To illustrate the application and utility of Geographic Information System (GIS) in exploring patterns of liver transplantation. Specifically, we aim to describe the geographic distribution of transplant registrations and identify disparities in access to liver transplantation across United Network of Organ Sharing (UNOS) region 1.

METHODS

Based on UNOS data, the number of listed transplant candidates by ZIP code from 2003 to 2012 for Region 1 was obtained. Choropleth (color-coded) maps were used to visualize the geographic distribution of transplant registrations across the region. Spatial interaction analysis was used to analyze the geographic pattern of total transplant registrations by ZIP code. Factors tested included ZIP code log population and log distance from each ZIP code to the nearest transplant center; ZIP code population density; distance from the nearest city over 50000; and dummy variables for state residence and location in the southern portion of the region.

RESULTS

Visualization of transplant registrations revealed geographic disparities in organ allocation across Region 1. The total number of registrations was highest in the southern portion of the region. Spatial interaction analysis, after adjusting for the size of the underlying population, revealed statistically significant clustering of high and low rates in several geographic areas could not be predicted based solely on distance to the transplant center or density of population.

CONCLUSION

GIS represents a new method to evaluate the access to liver transplantation within one region and can be used to identify the presence of disparities and reasons for their existence in order to alleviate them.

Model for end-stage liver disease score and MELD exceptions: 15 years later

The model for end-stage liver disease (MELD) score has been used as an objective scale of disease severity for management of patients with end-stage liver disease; it currently serves as the basis of an urgency-based organ-allocation policy in several countries. Implementation of the MELD score led to a reduction in waiting-list registration and waiting-list mortality and an increase in the number of deceased-donor transplants without adversely affecting long-term outcomes after liver transplantation (LT). The MELD score has been used for management of non-transplant patients with chronic liver disease. MELD exceptions serve as a mechanism to advance the needs of subsets of patients with liver disease not adequately addressed by MELD-based organ allocation. Several models have been proposed to refine and improve the MELD score as the environment within which it operates continues to evolve toward transplantation for sicker patients. The MELD score continues to serve and be used as a template to improve upon as an objective gauge of disease severity and as a metric enabling optimization of allocation of scarce donor organs for LT.

MELDEQ : An alternative Model for End-Stage Liver Disease score for patients with hepatocellular carcinoma

Multiple studies have demonstrated an advantage for hepatocellular carcinoma (HCC) patients under the current liver allocation system, such that the United Network for Organ Sharing (UNOS) recently voted in support of a proposal to delay granting Model for End-Stage Liver Disease (MELD) exception points to all HCC patients for 6 months, independently of a candidate's native MELD score or alpha-fetoprotein (AFP) level. We obtained UNOS data on adult patients who were added to the wait list between January 22, 2005 and September 30, 2009, and we explored the relationship between HCC, MELD, AFP, and other factors that contribute to not only dropout on the wait list but posttransplant survival as well. The aim was to establish an equivalent Model for End-Stage Liver Disease (MELDEQ ) score for HCC patients that would reduce the disparity in access to transplantation between HCC and non-HCC patients. We determined risk groups for HCC patients with dropout hazards equivalent to those of non-HCC patients, and we evaluated projections for HCC wait-list dropout/transplantation probabilities on the basis of the MELDEQ prioritization scheme. Projections indicate that lower risk HCC patients (MELDEQ  ≤ 18) would have dropout probabilities similar to those of non-HCC patients in the same MELD score range, whereas dropout probabilities for higher risk HCC patients would actually be improved. The posttransplant survival of all HCC risk groups is lower than that of their non-HCC counterparts, with 1-year survival of 0.77 (95% CI, 0.70-0.85) for MELDEQ scores ≥ 31. These results suggest that HCC patients with a combination of a low biochemical MELD score and a low AFP level (MELDEQ  ≤ 15) would receive a marked advantage in comparison with patients with chemical MELD scores in a similar range and that a delay of 6 months for listing may be appropriate. In contrast, patients with MELDEQ scores > 15 would likely be adversely affected by a universal 6-month delay in listing.

Competition in liver transplantation: helpful or harmful?

Improved outcomes of liver transplantation have led to increases in the numbers of US transplant centers and candidates on the list. The resultant and ever-expanding organ shortage has created competition among centers, especially in regions with multiple liver transplant programs. Multiple reports now document that competition among the country's transplant centers has led to the listing of increasingly high-risk patients and the utilization of more marginal liver allografts. The transplant and medical communities at large should carefully re-evaluate these practices and promote innovative approaches to restoring trust in the allocation of donor organs and confirming that there is nationwide conformity in the guidelines used for evaluating and listing potential candidates for this scarce resource.

Excess mortality on the liver transplant waiting list: unintended policy consequences and Model for End-Stage Liver Disease (MELD) inflation

The Model for End-Stage Liver Disease (MELD) allocation system for liver transplantation provides "exceptions" for diseases such as hepatocellular carcinoma (HCC). It was the aim of this study to assess equipoise between exception candidates and nonexception candidates on the waiting list and to assess if the exception system contributes to steadily increasing regional MELD at transplant. In all, 78,595 adult liver transplant candidates between January 2005 and December 2012 were analyzed. Yearly trends in waiting list characteristics and transplantation rates were analyzed for statistical association with MELD exceptions. Regional variations in these associations and the effect of exceptions on regional MELD scores at transplant were also analyzed. 27.29% of the waiting list was occupied by candidates with exceptions. Candidates with exceptions fared much better on the waiting list compared to those without exceptions in mean days waiting (HCC 237 versus non-HCC 426), transplantation rates (HCC 79.05% versus non-HCC 40.60%), and waiting list death rates (HCC 4.49% versus non-HCC 24.63%). Strong regional variation in exception use occurred but exceptions were highly correlated with waiting list death rates, transplantation rates, and MELD score at removal in all regions. In a multivariate model predicting MELD score at transplant within regions, the percentage of HCC MELD exceptions was the strongest independent predictor of regional MELD score at transplant.

CONCLUSION

Liver transplant candidates with MELD exceptions have superior outcomes compared to nonexception candidates and the current MELD exception system is largely responsible for steadily increasing MELD scores at transplant independent of geography.

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.

Toward a better liver graft allocation that accounts for candidates with and without hepatocellular carcinoma

In some countries where the Model for End-Stage Liver Disease (MELD) score is used for graft allocation, selected patients with hepatocellular carcinoma (HCC) receive a fixed number of exception points at listing, and increasing priority on the list by accruing additional exception points at regular time intervals. This system originally aimed at balancing the risks of HCC patients of developing contraindications and of non-HCC patients of dying before transplantation, is not ideal because it appears to offer an advantage to HCC patients, regardless of tumor characteristics and response to loco-regional treatment. Scores modulated by HCC characteristics have been proposed. They are based on a more refined estimate of the risk of pretransplant drop-out or of the posttransplant transplant benefit expressed as the life-years gained for each graft. This review describes the newly proposed systems, and discusses their advantages and drawbacks. We believe that the current exception points allocation should be revised and that drop-out-equivalent or transplant benefit-equivalent models should be studied further. As with all policy changes, these should be done under close monitoring that allows subsequent revisions.

Waiting time and explant pathology in transplant recipients with hepatocellular carcinoma: a novel study using national data

Risk factors for hepatocellular carcinoma (HCC) recurrence after liver transplantation have been well described. It has been surmised that longer time on the waitlist may select for tumors with a lower-risk of recurrence posttransplant, as patients with unfavorable tumor characteristics would be delisted due to tumor progression. Utilizing national explant pathology records from transplant recipients waitlisted with T2 HCC exception points, this study explored the correlation between waiting time and the development of pathologic HCC features associated with increased risk of tumor recurrence. Of 1976 explant pathology reports submitted nationally between April 8, 2012 and June 30, 2013, 1453 (73.5%) were from recipients with automatic T2 HCC exception points. There was no association between pretransplant waiting time and the proportion of HCC explants with either: (i) a poorly differentiated tumor; (ii) macrovascular invasion; (iii) HCC beyond Milan or University of California San Francisco criteria; (iv) HCC beyond the "up-to-seven" criteria; or (v) extra-hepatic or lymph node involvement. Though there was a statistically significant increase in microvascular invasion in recipients with pretransplant waiting 6-12 months, this association was not seen when adjusted for United Network for Organ Sharing region. These findings suggest that waiting time alone may not select for tumors with more favorable characteristics.