Some infections of the liver are caused by hepatitis C virus (HCV). Hepatitis C produces scar tissue in the liver, a condition known as cirrhosis. Cirrhosis is closely associated with the development of liver cancer. Doctors have observed that the risk for liver cancer decreases when patients with HCV infection are given the antiviral medication interferon. However, liver cancer is very difficult to cure. One of the treatments used to treat liver cancer involves injecting the cancerous nodules with alcohol, which kills the tumor cells. But even after the tumor cells have been killed, the cancer tends to recur. Doctors don't know whether patients with HCV infection who already have liver cancer will benefit from interferon treatment in addition to alcohol injections.