In its annual list of agents known to cause cancer, the U.S. government has included viruses for the first time. Hepatitis B and C were listed in the 11th edition of the U.S. Department of Health and Human Services' Report on Carcinogens.¹

"Hepatitis B virus (HBV) is known to be a human carcinogen based on sufficient evidence from studies in humans," the report stated. "Numerous cohort and case-control (epidemiological) studies conducted in populations differing by race or ethnicity and in various geographic regions have demonstrated that chronic HBV infection causes liver cancer."

The report described HCV in the same context, adding that this virus can cause liver cancer directly or indirectly, "the latter as a result of liver inflammation and regeneration associated with chronic hepatitis."

The newly added agents—hepatitis viruses, as well as lead and lead compounds, x-rays, compounds formed when meat or eggs are cooked at high temperatures, and various substances used in textile dyes, paints and inks—brings the total number of known carcinogens to 246.

The report cited an analysis of previous medical studies that found that people with HCV face 11.5 times the likelihood of developing hepatocellular carcinoma (the medical term for liver cancer) as those without HCV.

People diagnosed with hepatitis B face nearly 14 times the risk, the report noted.

1. U.S. Department of Health and Human Services (HHS). Public Health Service. National Toxicology Program. 11th Report on Carcinogens. Available at: http://ntp.niehs.nih.gov/ntp/roc/toc11.html. Accessed February 9, 2005.

John Martin is a long-time health journalist and an editor for Priority Healthcare. His credits include coverage of health news for the website of Fox Television's The Health Network, and articles for the New York Post and other consumer and trade publications.