Hepatocellular carcinoma and cholangiocarcinoma - Different prognosis, pathogenesis and therapy

Primary liver cancer is one of the most common cancer worldwide. Beside hepatocellular carcinoma (HCC), accounting for more than 80%, cholangiocarcinoma (CC) is the second most frequent primary malignant epithelial liver tumor. Combined hepatocellular-cholangiocarcinoma (HCC/CC) is a rare form of liver cancer with a frequency of 1%. Both, hepatocellular carcinoma and cholangiocarcinoma, show a wide geographical variation with low-incidence areas in North America and Europe and high incidence areas in Africa and Asia. Whereas hepatocellular carcinomas develop by malignant transformation of hepatocytes, cholangiocarcinomas arise from the small intrahepatic bile duct epithelium. The UICC-TNM classification of malignant liver tumors is applied for both tumor entities. 70-80% of hepatocellular carcinoma occur in cirrhotic liver. In high incidence areas, such as Asia and Africa, HCC is strongly associated with chronic viral hepatitis B and C and liver cirrhosis. Nutritional factors, toxins and metabolic diseases contribute also to hepato-carcinogenesis. The etiology of cholangiocarcinoma remains unclear, most occur in absence of known etiological factors. But several risk factors including hepatolithiasis, liver fluke infection, and anatomical abnormalities associated with inflammation of the biliary tract have been described.