Characteristics and outcome of incidental hepatocellular carcinoma after liver transplantation: a cohort study.

INTRODUCTION Despite advances in imaging diagnostic modalities, hepatocellular carcinoma is sometimes incidentally diagnosed on histological examination of the liver explant. Our objectives were: 1) To compare the characteristics between incidental and known hepatocellular carcinoma and 2) To estimate survival and tumor recurrence after liver transplantation. MATERIAL AND METHODS Retrospective, single-center study. The inclusion criteria were 1) cirrhotic patients, age≥18 years, 2) Liver transplantation between 1998 and 2018, and 3) hepatocellular carcinoma diagnosed on the histopathologic examination of the explanted liver. Cholangiocarcinoma and patients with early retransplantation were excluded. Multivariate analysis was performed using binomial logistic regression to assess the factors associated incidental hepatocellular carcinoma. Kaplan-Meier curves were plotted to explore the impact on overall survival and recurrence free survival. RESULTS 269 patients were enrolled. The prevalence of incidental hepatocellular carcinoma was 4.18% (95% CI: 2.89-6.01%) of all liver transplants performed in cirrhotic patients. The median diameter of the main nodule was smaller in incidental hepatocellular carcinoma (20 vs 27 mm, p=0.004) although they were more likely to be beyond the Up-to-Seven criteria on explant examination (22.2% vs 7.5%, p=0.001), showing no differences in any other histological features. No differences were found in overall survival rates (incidental 70.2% vs 70.4%, p=0.87) nor recurrence-free survival (incidental 100% vs 83.8%, p=0.07) at 5 years. CONCLUSION Incidental hepatocellular carcinoma has a smaller size and is more frequently found to be beyond the Up-to-Seven criteria. However, no differences were found in overall survival rates nor recurrence-free survival, although there was no tumor recurrence in incidental hepatocellular carcinoma group.