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Small-for-size graft in liver transplantation outside Milan criteria presents worse outcomes

Patients who received small-for-size grafts during liver transplantation for hepatocellular carcinoma outside Milan criteria had worse rates of recurrence and survival compared with patients within Milan criteria, according to a recently published study.

“A major limitation of [living donor liver transplantation (LDLT)] is the size of the liver graft that can be obtained safely from living donors,” the researchers wrote. “Small-for-size grafts (SFSGs) cannot appropriately deal with the portal flow in the recipient due to decreased liver volume. Shear stress caused by transient portal hypertension can cause acute mechanical injury, which then induces severe inflammatory responses to negatively affect the outcomes of liver transplantation (LT). Reports showed that SFSG causes graft dysfunction following LT and adversely affects graft survival despite rapid hepatic regeneration.”

The study comprised 246 patients with a graft-to-weight ratio of 0.8% or higher and 82 patients with a graft-to-weight ratio less than 0.8%. Mean patient age was 54.5 years and 82.3% were men; mean donor age was 33.4 years and 50.6% were men. The right lobe of the liver was used in all cases.

Among those with a graft-to-weight ratio less than 0.8%, the recurrence-free survival rates were 75.9% at 1 year, 73.3% at 3 years and 71.7% at 5 years . For those with a graft-to-weight ratio of 0.8% or higher, the rates were 86.4% at 1 year, 80.8% at 3 years and 77.9% at 5 years.

Similarly, the overall survival rates for those with a graft-to-weight ratio less than 0.8% were 87.8% at 1 year, 80.3% at 3 years and 78.7% at 5 years and, among those with a ratio of 0.8% or higher, the rates were 93.8% at 1 year, 87.1% at 3 years and 84.1% at 5 years.

Finally, the 30-day mortality rates were 1.2% in the lower graft-to-weight ratio group and 0.4% in the higher graft-to-weight ratio group. Between the two groups, the researchers observed no significant difference between recurrence-free, survival or 30-day mortality rates.

Outside Milan criteria

In a subgroup analysis of patients outside the Milan criteria, however, the results were significantly different.

Thirty-five patients with graft-to-weight ratio less than 0.8% and 112 patients with graft-to-weight ratio of 0.8% or higher were outside Milan criteria at time of transplantation.

The recurrence-free survival rates among patients with a graft-to-weight ratio less than 0.8% were 52.4% at 1 year, 49.3% at 3 years, and 49.3% at 5 years and, for those with a ratio of 0.8% or higher, the rates were 76.5% at 1 year, 68.3% at 3 years and 64.3% at 5 years, which was significantly worse than patients in Milan criteria (P = .049).

Further, the overall survival rates among those in the lower graft-to-weight ratio group were 77.1% at 1 year, 65.3% at 3 years and 61.5% at 5 years and in the higher graft-to-weight ratio group they were 90.2% at 1 year, 80.1% at 3 years and 77.5% at 5 years, which was significantly different compared with patients in Milan criteria (P = .047).

“The rates of not only intrahepatic recurrence but also extrahepatic recurrence were significantly increased for these patients,” the researchers wrote. “Considering that the extended criteria beyond the guidelines of Milan or [University of California, San Francisco (UCSF)] criteria are commonly applied in LDLT for HCC in many centers, recipients’ oncological outcomes can be improved by giving more care to liver graft size during donor selection.” – by Talitha Bennett

Disclosure: The authors report no relevant financial disclosures.