Incidence of primary liver cancer and aetiological aspects: a study of a defined population from a low-endemicity area.

The prevalence of primary liver cancer (PLC) varies throughout the world. It has been attributed to variations in incidence of the predominant histological type, hepatocellular carcinoma (HCC). The incidence of PLC types other than HCC such as cholangiocellular carcinoma (CCC) is far less known, especially in low-incidence areas. The aetiology of HCC and other PLC types is obscure, with the exception of the association between HCC and cirrhosis as well as chronic viral hepatitis. The present retrospective incidence and aetiology study concerns a well-defined population from a period with a high autopsy frequency. Preserved biopsy specimens were re-evaluated histopathologically and patient records were studied. Among 590 histologically verified cases of PLC, HCC constituted 90%, CCC 8% and a mixed form of these types 1%. At the end of the study period the annual age-standardised incidence rate of HCC was 3.6 cases per 100,000 inhabitants. Other PLC types were hepatoblastoma (n = 3), fibrolamellar carcinoma (n = 2), angiosarcoma (n = 1) and infantile haemangioendothelioma (n = 1), each constituting less than 1% of the PLC cases. Comparing HCC with CCC we found that cirrhosis (70%) and alcoholism (21%) was significantly more frequent in HCC, and cholelithiasis was significantly more common (60%) in patients with CCC. In the majority of the PLC cases with liver cirrhosis this disorder was unknown before diagnosis of the tumour.