Etiology and Risk Factors

393 H epatocellular carcinoma (HCC), or hepatoma, is the fifth most common of all malignancies worldwide and results in approximately one million deaths annually (Yu & Keeffe, 2003). Although the incidence of HCC is highest in parts of Africa and Asia, recent studies have documented a clear rise in the number of cases in Western Europe, Japan, and the United States (Di Bisceglie, 2002; Nakakura & Choti, 2000). The epidemiology and characteristics of HCC can differ depending on the biology of the cancer reflected in various geographic locations in the world (Llovet & Beaugrand, 2003; Omata et al., 2002; Rilling & Drooz, 2002; Venook, 2000); however, this article focuses on HCC in the United States. Although HCC is uncommon in the United States, its prevalence has increased by nearly 75% since the 1980s, with an overall incidence of 2.40–3.23 cases per 100,000 (Cha, DeMatteo, & Blumgart, 2002; Di Bisceglie, 2002; El-Serag & Mason, 1999; Hammett & Gollan, 2001; Hassan, Frome, Patt, & El-Serag, 2002). The recent rise in incidence has been linked to an increased prevalence of hepatitis and better diagnostic techniques (Cha et al.; El-Serag & Mason; Koea, 2001; Llovet & Beaugrand, 2003). In the United States, HCC occurs more frequently in men than women by a ratio of three to one, rates in African American populations are approximately twice as high as in Caucasians, and older age is associated with a higher incidence of HCC (Di Bisceglie; El-Serag & Mason). The reason for the difference in incidence between the sexes may be attributed to a higher incidence of hepatitis B virus (HBV), hepatitis C virus (HCV), and alcoholism in men. In addition, HBV and HCV are more prevalent among African Americans than Caucasians (El-Serag & Mason; Koea).