Mortality after Transplantation for Hepatocellular Carcinoma: A Study from the European Liver Transplant Registry.

Background and Aims: Prognosis after liver transplantation differs between hepatocellular carcinoma (HCC) arising in cirrhotic and non-cirrhotic livers and aetiology is poorly understood. The aim was to investigate differences in mortality after liver transplantation between these patients. Methods: We included patients from the European Liver Transplant Registry transplanted due to HCC from 1990 to November 2016 and compared cirrhotic and non-cirrhotic patients using propensity score (PS) calibration of Cox regression estimates to adjust for unmeasured confounding. Results: We included 22,787 patients, of whom 96.5% had cirrhosis. In the unadjusted analysis, non-cirrhotic patients had an increased risk of overall mortality with a hazard ratio (HR) of 1.37 (95% confidence interval [CI] 1.23-1.52). However, the HR approached unity with increasing adjustment and was 1.11 (95% CI 0.99-1.25) when adjusted for unmeasured confounding. Unadjusted, non-cirrhotic patients had an increased risk of HCC-specific mortality (HR 2.62, 95% CI 2.21-3.12). After adjustment for unmeasured confounding, the risk remained significantly increased (HR 1.62, 95% CI 1.31-2.00). Conclusions: Using PS calibration, we showed that HCC in non-cirrhotic liver has similar overall mortality, but higher HCC-specific mortality. This may be a result of a more aggressive cancer form in the non-cirrhotic liver as higher mortality could not be explained by tumour characteristics or other prognostic variables.