Chronic hepatitis B virus infection is associated with the risk for nonliver cancers, especially digestive system cancers, according to findings from a population-based cohort study published in JAMA Network Open.
“In a large prospective Chinese cohort of 496,732 adults, we found that participants who were (hepatitis B surface antigen (HBsAg)] seropositive were at an increased risk of developing [hepatocellular carcinoma (HCC)] and several nonliver cancers, including stomach cancer, oral cancer, colorectal cancer, pancreatic cancer, and lymphoma,” Ci Song, MD, from Nanjing Medical University in China, and colleagues wrote.
Song and colleagues analyzed the China Kadoorie Biobank (CKB) — a study from 2004 to 2008 that investigated the primary environmental and genetic causes of common chronic diseases in the Chinese population. In the study, researchers used a dipstick assay to detect serum HBsAg among the nearly 500,000 participants to determine the association between HBV infection and risk for all cancer types, according to the study.
The mean age of the cohort was 51.5 years, and 59% of participants were women. Participants who were HBsAg seropositive (n = 15,355) had a higher risk for HCC (HR = 15.77; 95% CI, 14.15-17.57), stomach cancer (HR = 1.41.; 95% CI, 1.11-1.8), colorectal cancer (HR = 1.42; 95% CI, 1.12-1.81), oral cancer (HR = 1.58; 95% CI, 1.01-2.49), pancreatic cancer (HR = 1.65; 95% CI, 1.03-2.65) and lymphoma (HR = 2.1; 95% CI, 1.34-3.31) compared with participants who were HBsAg seronegative (n = 481,377), according to the study.
Hepatitis B virus infection affects more than 2 billion people worldwide.
Source: CDC/ Dr. Erskine Palmer
The researchers analyzed two smaller cohort studies to validate the associations they found in the CKB study. A cohort from Qidong County in Jiangsu Province (n = 37,336) validated associations between HBV and HCC (HR = 17.51; 95% CI, 13.86-22.11) and stomach cancer (HR = 2.02; 95% CI, 1.24-3.29). The second small cohort (n = 17,723), a nested case-control study from Changzhou City, also in Jiangsu Province, validated only an association between HBV infection and stomach cancer (OR = 1.76; 95% CI, 1.04-2.98).
“This study provides compelling evidence for the association between HBV infection and all types of cancer,” Song and colleagues wrote. “Strengths of the CKB study included its prospective design, the inclusion of a geographically widespread Chinese population living in urban and rural areas, and careful adjustment for potential confounders.”
However, they also noted some study limitations, including the rate of HBsAg positivity among the CKB cohort, which was 3.1% lower than a rate found in a national serosurvey.
“The low detection rate may lead to a neglectable false-negativity,” the researchers wrote.
They also said further tests involving more nonliver tissues are warranted to confirm the HBV DNA-positive rate and the strength of the association they found between HBV and extrahepatic cancer. – by Joe Gramigna
Disclosures: The authors report no relevant financial disclosures.