Survival rates after liver transplants
Mar 2, 2007 - 12:57:59 PM
Survival rates are similar among patients with hepatitis B who are listed for liver transplantation, whether or not they have hepatocellular carcinoma (HCC), according to a new study in the March 2007 issue of Liver Transplantation. An accompanying editorial suggests that these results affirm the current policy on the allocation of donor livers.
The study and the editorial appear in the March 2007 issue of Liver Transplantation, the official journal of the American Association for the Study of Liver Diseases (AASLD) and the International Liver Transplantation Society (ILTS). The journal is published on behalf of the societies by John Wiley & Sons, Inc. and is available online via Wiley InterScience athttp://www.interscience.wiley.com/journal/livertransplantation.
The United Network for Organ Sharing (UNOS) utilizes the Model for End-Stage Liver Disease (MELD) to determine allocation of available organs. Patients with hepatocellular carcinoma have higher MELD scores, and may be more likely to receive transplants quickly compared to patients with other types of liver disease. Without transplant, many HCC patients die or become unsuitable for transplantation because of tumor progression.
Led by Anna S. Lok, M.D. of the Division of Gastroenterology at the University of Michigan, researchers set out to compare clinical outcomes for hepatitis B patients awaiting a liver transplant, whether or not they had HCC. They enrolled 279 patients from the National Institutes of Health-sponsored HBV-OLT study between November 2001 and June 2005. Of these patients 183 had HBV with cirrhosis, and 96 had HBV with HCC. Most were receiving antiviral therapy. The researchers collected demographic and laboratory data for all participants, and computed a MELD score for each. They then followed the patients for a median of 30.2 months.
The patients with HBV-HCC were older, more likely to be Asian and had less severe liver impairment than patients with HBV-cirrhosis; 78 percent underwent liver transplantation, compared to 51 percent of patients with HBV-cirrhosis. Despite this difference, 5-year survival rates were similar: 73 percent of the HBV-HCC group, compared to 78 percent of the HBV-cirrhosis group. The 5-year survival rates for patients who did not receive a transplant were also very similar: 82 percent of the HBV-HCC group versus 79 percent of the HBV-cirrhosis group. It should be noted that 71% of the patients in the HBV-HCC group who had not been transplanted had received some form of HCC treatment including surgical resection and the number of patients alive without transplant 5 years after listing was very small (n=6).
"Despite more advanced liver disease and a lower rate of transplantation, intention-to-treat survival of patients listed for HBV-cirrhosis was comparable to those with HBV-HCC, possibly related to beneficial effects of antiviral therapy. However, these data may not apply to patients with liver disease due to other etiologies for which safe and effective therapies that can improve or stabilize liver disease in those with decompensated cirrhosis are not available" the authors conclude.
In an accompanying editorial, Myron Schwartz and colleagues from the Mount Sinai Liver Cancer Program at the Mount Sinai School of Medicine in New York say the study vindicates UNOS policy while reporting a surprising finding: survival without transplantation was excellent and equal between the two groups, with 5-year survival in patients not transplanted actually better than the survival for the entire cohort.
"This figure calls into question the basis for placing these patients on the waiting list in the first place," the authors write. Furthermore, since previous studies have shown that 5-year survival for HCC patients without treatment is unusual, "the accuracy of the diagnosis of HCC in these is questionable," they say.
The Wong study does show that UNOS policy helps patients with high MELD scores get a liver transplant, and that their prioritization does not affect outcomes for non-HCC patients with HBV. "The refinement of the UNOS algorithm to optimally balance the risks for HCC and non-HCC liver transplant candidates remains a work in progress," conclude the authors.
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