Natural history and pathogenesis of hepatitis C virus related hepatocellular carcinoma

Generally, 0.4-2.5% of patients with chronic hepatitis C virus (HCV) infection develop hepatocellular carcinoma (HCC). HCC occurs more often in patients with cirrhosis and in those with increased liver cell proliferation. HCV-related tumors occur in older patients and often have a less aggressive course than HCC, related to other etiological factors. Many HCV-related HCC are multifocal in origin. However, many tumors grow as a single hepatic nodule for years before generating satellite or distant tumor nodules. The growth pattern varies from one tumor to another, with tumor volume doubling times ranging from 1 to 20 months. Tumor progression and hepatic failure are the leading causes of death in most patients. Using the polymerase chain reaction technique, HCV-RNA has been almost invariably detected in serum and tumor tissue of anti-HCV patients with HCC. In many patients, HCV-RNA was found to belong to the possibly more pathogenic type Ib. However, it is unlikely that HCV plays a direct role in liver tumorogenesis, since no reverse transcriptase activity has been found in infected livers. One current opinion is that HCV may promote cancer through cirrhosis, which is per se an important risk factor for this tumor. In HCV carriers, the risk of developing HCC and having more severe tumor disease may be increased by coexisting hepatitis B virus (HBV) or alcohol abuse, further supporting the idea that both HCC and cirrhosis might be a result of the interplay of several risk factors. HCC could also be the consequence of HCV interacting with cellular genes that regulate cell growth and differentiation, independent of the effect of cirrhosis.