The finding comes from a retrospective analysis published online January 10 in the Journal of the American College of Surgeons.
Lead author Clark Gamblin, MD, Medical College of Wisconsin, Milwaukee, said the new findings are “intriguing” but need to be validated.
“It is certainly premature to recommend a change in compatibility screening criteria based on our findings alone,” Gamblin said in a press statement.
Currently, race is not a factor in compatibility screening of donors for liver transplant, he said.
The study authors also acknowledged that the study offers no insight into any “potential, suspected mechanism driving these results and whether the increased survival is the result of specific unknown genetic similarity, biochemical process or from a more loosely-defined socioeconomic or cultural phenomenon.”
However, they also say that the significance of the race-related findings is in part derived from the fact that long-term survival from liver cancer is worse for black Americans than for other racial groups.
Compared to other races, overall survival is worse for black American liver cancer patients who undergo liver transplant — and that was the case in the new study, too.
Specifically, in the new results, among American patients with liver cancer who underwent transplant, the 5-year survival rate for blacks was 58.6%, compared with 68.1% for whites, 71.4% for Hispanics, and 74.7% for Asians (P < .001).
Thus, anything that might improve survival among black liver cancer patients who undergo transplant is worth investigating, suggested Gamblin.
He and his coauthors also note that liver transplant is a curative treatment option for some patients with early-stage liver cancer.
In the new study, the authors reviewed the Organ Procurement and Transplantation Network database and identified 15,141 adults of all races with hepatocellular carcinoma who received a liver transplant from 1994 to 2015.
A total of 1384 of the transplant recipients (9.1%) were black. Of those, 325 patients (23.5%) received livers from African American donors (matched). The other 1059 black patients (76.5%) received livers from other races (unmatched).
Among these black transplant recipients, matched patients experienced significantly better median overall survival, which was the primary outcome, when compared to the unmatched cohort (135 vs 78 months; P = .007).
For matched patients, 5-year survival was also better (64.2% vs 56.9%; P = .019)
Multivariate analysis, which controlled for characteristics important to transplant success and subsequent survival, showed an adjusted hazard ratio of 0.66 for race-matched transplants (95% confidence interval: 0.49 – 0.88; P = .004). However, this survival advantage with race-matching did not emerge until after 1 year.
In their article, the authors place their findings in a larger context. The most recent national data (2011-2015) show that 18% of liver donors in the United States were black and that only 25% of black patients received a liver from a black donor.
“The survival advantage shown in the current analysis provides evidence that the observed increase in race-matched transplants over time may contribute to improved long-term survival for the African American population,” they comment.
Gamblin emphasized that these data alone are not yet enough to lead to protocol changes and that “recipients should not turn down a liver based on the race of the donor, because they may not get another one,” referring to the nationwide organ shortage.
“There are not enough donors, and people on the waiting list are dying every day waiting for an organ,” he said.
Data from the Organ Procurement and Transplantation Network suggest that more than 13,500 people were waiting to undergo a liver transplant at the end of 2018.
Gamblin said that it was his “hope that everyone consider liver donation; there are not enough donors, and people on the waiting list are dying every day waiting for an organ.”
The study was first presented in August 2018 at the Sixth Annual Solid Organ Transplant Symposium in Milwaukee.
The study authors have disclosed no relevant financial relationships.
J Am Coll Surg. Published online January 10, 2019. Abstract