Hepatitis B linked to bile duct cancer

There is an association between hepatitis B virus (HBV) infection and an increased risk of extrahepatic bile duct cancer. The extrahepatic bile duct collects bile from the liver, but is located outside of the liver. It joins with another duct coming from the gallbladder to form the common bile duct, which carries bile to the small intestine. Cancers of the extrahepatic bile duct are unusual and very difficult to treat. To understand this association better, American researchers examined the prevalence of HBV and hepatitis C (HCV) infection in 417 patients with biliary tract cancers, 517 with biliary stones, and 762 randomly selected healthy comparison controls. Among the population controls, HBV infection was detected in more than seven per cent patients. Patients with extrahepatic bile duct cancer were more likely to test positive for HBV (more than 14 per cent). This, in turn, resulted in a 2.4-fold increased risk of extrahepatic bile duct cancer. There was no significant association between HBV and gallbladder cancer, bile duct stones and gallbladder stones. It was also found that there was a low prevalence of HCV infection in this population (two per cent), which limited the ability to estimate the association between this infection and biliary disease. As HBV induces liver cancer primarily by causing chronic inflammation and tissue destruction with regeneration of liver cells, a similar process may be involved in bile duct cancers.