Hepatitis B tied to bile duct cancer outside liver

NEW YORK (Reuters Health) - The results of a study published in the International Journal of Cancer suggest 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.

In a population-based study conducted in Shanghai, Dr. Ann W. Hsing, of the National Cancer Institute, Bethesda, Maryland, and colleagues examined the prevalence of HBV and hepatitis C infection in 417 patients with biliary tract cancers, 517 with biliary stones, and 762 randomly selected healthy comparison subjects.

Among the population controls, HBV infection was detected in 7.3 percent. Patients with extrahepatic bile duct cancer were more likely to test positive for HBV (14.2 percent). 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.

The team found a low prevalence of HCV infection in this population (2 percent), which limited the ability to estimate the association between this infection and biliary disease.

HBV induces liver cancer primarily by causing chronic inflammation and tissue destruction with regeneration of liver cells, Hsing's team notes. A similar process may be involved in bile duct cancers," they suggest.

SOURCE: International Journal of Cancer, April 15, 2008.