Epidemiology

Hepatitis B viral load, genotype affect risk of liver cancer

Last Updated: 2005-02-18 12:57:16 -0400 (Reuters Health)

By Megan Rauscher

NEW YORK (Reuters Health) - Prospective study findings indicate that blood hepatitis B virus DNA levels and genotype are important markers for defining high-risk patients for antiviral treatment among HBV carriers 30 years of age or older.

According to the study, published in the February 16th issue of the Journal of the National Cancer Institute, higher plasma HBV DNA levels and infection with HBV genotype C are independently and additively associated with an increased risk of hepatocellular carcinoma (HCC).

"HBV is probably the etiological agent for approximately 60% of all HCCs," Dr. Ming-Whei Yu from National Taiwan University in Taipei noted in comments to Reuters Health. "The HCC risk is 20-fold higher for HBV carriers than for HBV noncarriers, but only a fraction of HBV carriers are expected to develop HCC in their lifetime."

In a long-term follow-up study of 4841 Taiwanese male HBV carriers age 30 years or older, Dr. Yu's team found that men with blood HBV DNA levels of 4.23 log10copies/mL or greater had between a two- to seven-fold higher risk of developing HCC than those with blood HBV DNA levels of 3.62 log10copies/mL or less.

Additionally, infection with HBV genotype C was associated with an approximately five-fold increased risk for HCC compared with infection with other genotypes (almost all type B). Moreover, there was an additive effect between HBV DNA levels and genotype.

For example, men infected with genotype C HBV and HBV DNA levels greater than 5.90 log10copies/mL had a 26.5-fold higher risk of HCC than men with other HBV genotypes and HBV DNA levels less than 4.23 log10copies/mL.

"The observation that HBV carriers with HBV DNA levels greater than 4.22 log10 copies/mL have at least a two-fold excess risk of HCC compared with HBV carriers with lower HBV DNA levels provides information to define a virologic response representing the long-term clinical improvement for future anti-HBV therapy," Dr. Yu told Reuters Health.

In an editorial, Dr. James J. Goedert from the National Cancer Institute in Bethesda, Maryland says this study "provides strong evidence that HBV genotypes matter."

"Despite advances in pharmacology, virology, and epidemiology, challenges to reducing HCC incidence and mortality abound," he writes.

"The slow, but sure, approach to reducing liver cancer mortality over the next 50 years is primary prevention of HCC by universal HBV vaccination," he contends.

J Natl Cancer Inst 2005;97:245-246,265-272.