Prolonged, heavy drinking has been associated in many cases with primary liver cancer. However, it is liver cirrhosis, whether caused by alcohol or another factor, that is thought to induce the cancer. In areas of Africa and Asia, liver cancer afflicts 50 or more people per 100,000 per year, usually associated with cirrhosis caused by hepatitis viruses. In the United States, liver cancer is relatively uncommon, afflicting approximately 2 people per 100,000, but excessive alcohol consumption is linked to as many as 36 percent of these cases by some investigators.