Hepatitis C Virus Studied as Risk Factor in Liver Cancer

Infectious Disease Special Edition ISSUE: JANUARY 2012 | VOLUME: 1

by George Ochoa

Two Mayo Clinic studies have clarified the importance of chronic hepatitis C virus (HCV) in the rising trend of liver cancer, or hepatocellular carcinoma (HCC).

One study (Yang et al. Mayo Clin Proc. 2012;87:9-16) analyzed longitudinal trends in the incidence, etiology, treatment of HCC and survival in community residents in Olmsted County, Minn. The researchers found that in earlier periods (1976-1990, 1991-2000), alcohol use was the most common risk factor, but, in 2001 to 2008, HCV filled that role. At the same time, HCC incidence rose dramatically, from 3.5 per 100,000 person-years for the 1976 to 1990 time period, to 3.8 for the period from 1991 to 2000, to 6.9 for the 2001 to 2008 period.

Study author W. Ray Kim, MD, associate professor of medicine, Mayo Clinic College of Medicine, Rochester, Minn., wrote in an email: “The biggest and unique risk factor of HCC is underlying liver disease. Our data showed that previously alcohol, more recently HCV has become the underlying cause.”

The second study (Shire et al. Mayo Clin Proc. 2012;87:17-24) investigated a sample of Somali immigrants seen at Mayo Clinic from July 1, 1996, to Oct. 31, 2009. Non-Somali Olmsted County residents served as controls. The frequencies of chronic hepatitis B virus (HBV) and HCV, and their associations with HCC, were studied. Both HBV and HCV occurred frequently in the sample of Somalis, but HCV was the major risk factor for HCC. There were significant differences in the HCV genotype distributions between Somalis and non-Somalis.

The high prevalence of HCV in the Somali sample came as a surprise to the researchers. “We didn’t expect it,” Abdirashid M. Shire, PhD, assistant professor of medicine, Division of Gastroenterology and Hepatology, Mayo Clinic College of Medicine, said in an interview. The study, Dr. Shire added, “supports the value of early detection” of HCV. “It’s very important to screen for HCV.” Dr. Kim reported that his study also “indirectly” supports the value of early detection and treatment to improve outcomes.

—Drs. Kim and Shire had no relevant financial disclosures.

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