Combined hepatocellular-cholangiocarcinoma: An update on epidemiology, classification, diagnosis and management

Combined hepatocellular-cholangiocarcinoma (CHC) is a rare subtype of primary hepatic malignancies, with variably reported incidence between 0.4%–14.2% of primary liver cancer cases. This study aimed to systematically review the epidemiological, clinicopathological, diagnostic and therapeutic data for this rare entity. We reviewed the literature of diagnostic approach of CHC with special reference to its clinical, molecular and histopathological characteristics. Additional analysis of the recent literature in order to evaluate the results of surgical and systemic treatment of this entity has been accomplished. The median age at CHC's diagnosis appears to be between 50 and 75 years. Evaluation of tumor markers [alpha fetoprotein (AFP), carbohydrate antigen 19–9 (CA19–9) and carcinoembryonic antigen (CEA)] along with imaging patterns provides better opportunities for CHC's preoperative diagnosis. Reported clinicopathologic prognostic parameters possibly correlated with increased tumor recurrence and grimmer survival odds include advanced age, tumor size, nodal and distal metastases, vascular and regional organ invasion, multifocality, decreased capsule formation, stem-cell features verification and increased GGT as well as CA19–9 and CEA levels. In case of inoperable or recurrent disease, combinations of cholangiocarcinoma-directed systemic agents display superior results over sorafenib. Liver-directed methods, such as transarterial chemoembolization (TACE), percutaneous ethanol injection (PEI), hepatic arterial infusion chemotherapy (HAIC), radioembolization and ablative therapies, demonstrate inferior efficacy than in cases of hepatocellular carcinoma (HCC) due to CHC's common hypovascularity. CHC demonstrates an overlapping clinical and biological pattern between its malignant ingredients. Natural history of the disease seems to be determined by the predominant tumor element. Gold standard for diagnosis is histology of surgical specimens. Regarding therapeutic interventions, major hepatectomy is acknowledged as the cornerstone of treatment whereas minor hepatectomy and liver transplantation may be applied in patients with advanced cirrhosis. Despite all therapeutic attempts, prognosis of CHC remains dismal.