Treatments and prognostic outcomes of combined hepatocellular-cholangiocarcinoma with distant metastasis: an analysis based on SEER data

Background: Combined hepatocellular-cholangiocarcinoma (cHCC-CCA) is a rare liver cancer with a poor prognosis, often diagnosed at an advanced stage. The management of cHCC-CCA with distant metastasis remains challenging, and prognostic factors are not well-defined. This study aimed to investigate prognostic factors and treatment outcomes for cHCC-CCA patients with distant metastasis. Methods: Retrospective analysis was conducted using data from the National Cancer Institute Surveillance, Epidemiology, and End Results (SEER) database. Patients with distant metastasis [stage M1, according to the American Joint Committee on Cancer (AJCC) 7th edition] between January 2010 and December 2020 were included. Their characteristics, clinical profiles, and prognostic information were evaluated. Cox multifactorial survival analysis and Kaplan-Meier survival curves were used for statistical analysis. Results: A total of 130 patients were included, with 78 (60%) receiving chemotherapy. Cox multivariate survival analysis revealed worse prognosis for Black individuals compared to White individuals (P<0.05). The median overall survival was 2 months for Black patients and 5 months for White patients. Chemotherapy significantly improved patient prognosis (P<0.05), while lung metastasis emerged as an independent risk factor (P<0.05). Kaplan-Meier survival curves confirmed the impact of lung metastasis and chemotherapy on overall survival. Patients with lung metastasis had lower survival rates (P<0.05), and those receiving chemotherapy had higher survival rates (P<0.05). Subgroup analysis based on age showed lower survival rates in patients aged 75 years or older compared to those below 75 years. Chemotherapy showed significant beneficial effects on the prognosis of patients below 75 years old, but no significant difference was observed in patients aged 75 years or above. Conclusions: Chemotherapy improves the prognosis of cHCC-CCA patients with distant metastasis, especially for those under 75 years old. Black race and lung metastasis are poor prognostic factors.