Clinicopathological analysis of colorectal cancer liver metastasis and intrahepatic cholangiocarcinoma: are they just apples and oranges?

Intrahepatic cholangiocarcinoma and colorectal cancer liver metastasis are the most primary and secondary adenocarcinoma of the liver, respectively. A large-scale long-term comparative study of these two cohort patient is lacking.A total of 166 colorectal cancer liver metastasis patients and 206 intrahepatic cholangiocarcinoma patients who had undergone curative liver resection were retrospectively analysed. Among 206 intrahepatic cholangiocarcinoma, there were 47 intraductal growth type-intrahepatic cholangiocarcinoma and 159 non-intraductal growth type-intrahepatic cholangiocarcinoma. The demographics, clinicopathological data, immunohistochemical study and survival were analysed.The intrahepatic cholangiocarcinoma patients were more female-predominated, associated with hepatolithiasis, symptomatic, jaundiced, and with larger tumour size compared with those of colorectal cancer liver metastasis. Prognostic factors of intrahepatic cholangiocarcinoma were pathologic staging, histologic pattern and section margin; whereas prognostic factors of colorectal cancer liver metastasis were rectal origin, differentiation, section margin and bilobar distribution. CK7 and CK20 differentiated majority of intrahepatic cholangiocarcinoma from colorectal cancer liver metastasis, while CDX2 and MUC5AC helped to differentiate inconclusive cases. The 1-, 3-, 5- and 10-year survival rates of colorectal cancer liver metastasis were 77%, 31%, 20% and 14%, compared to 53%, 21%, 13% and 7% of intrahepatic cholangiocarcinoma (p=.0001). Furthermore, the survival of colorectal cancer liver metastasis was comparable to staged II intrahepatic cholangiocarcinoma (p=.8866) and intraductal growth type-intrahepatic cholangiocarcinoma (p=.1915).Demographics, precipitating factor, clinical manifestations, and prognostic factors of colorectal cancer liver metastasis and intrahepatic cholangiocarcinoma differed remarkably. High incidence of CDX2 and MUC2 expression in colorectal cancer liver metastasis and intraductal growth type-intrahepatic cholangiocarcinoma might explain their similar cytoarchitecture and survival.