Liver transplantation versus resection for patients with combined hepatocellular cholangiocarcinoma: A retrospective cohort study

Background: Combined hepatocellular cholangiocarcinoma (CHC) is a rare primary liver cancer, and whether liver transplantation should be implemented among CHC patients is still controversial. We intend to conduct a retrospective cohort study based on the Surveillance, Epidemiology, and End Results (SEER) database to investigate the prognosis of liver transplantation vs. liver resection among CHC patients.Methods: Patients diagnosed with CHC (ICD-O-3:8180/3) and treated with transplantation or hepatectomy were extracted from the SEER database (2000-2018). We utilized Propensity Score Matching to control confounding bias. Kaplan-Meier curve was used for survival analysis, and Cox regression was used to find independent factors associated with prognosis.Results: We identified 123 (transplantation: 49; resection: 74) patients with CHC who were treated between 2004 and 2015. In the entire cohort, survival analysis demonstrated transplantation group was associated with better overall survival and cancer-specific survival (log-rank p = 0.004 and p = 0.003, respectively). In addition, liver transplantation still conferred better overall and cancer-specific survival than liver resection after Propensity Score Matching (log-rank p = 0.024 and p = 0.048, respectively). However, this advantage didn't appear in the subgroup, regardless of whether the tumor size was greater than 3 cm or not. (<= 3 cm: OS log-rank p = 0.230, CSS log -rank p = 0.370; >3 cm: OS log-rank p = 0.110, CSS log-rank p = 0.084). Multivariate analysis validated the finding that liver transplantation was a protective factor for overall survival (HR = 0.55 [0.31-0.95], p = 0.032).Conclusions: Liver transplantation may be an option in individuals with CHC and should be taken into consideration due to its advantages in terms of overall survival and cancer-specific survival. However, a sizable sample is required for future studies to determine which subset of CHC pa-tients may benefit more from liver transplantation.