Researchers at The University of Texas MD Anderson Cancer Center have discovered that exposure to the hepatitis B virus ( HBV ) may increase the risk of pancreatic cancer.
The study, published in the Journal of Clinical Oncology, also suggests that patients with this lethal form of cancer treated with chemotherapy may face danger of reactivation of their HBV.
Pancreatic cancer is diagnosed in 37,000 people in the United States each year, and more than 34,000 people die of the disease annually, according to the American Cancer Society. It is often diagnosed in the late stages and is especially perplexing because few risk factors are known.
HBV and hepatitis C virus ( HCV ) are major global health problems, affecting about 2 percent of the population worldwide. In the United States 1.25 million people have chronic HBV, while 3.2 million have chronic HCV. These systemic viruses can harm the body in a variety of ways, including traveling through the bloodstream and damaging tissues throughout the body.
Previous research has shown HBV and HCV are major causes of liver cancer. Little is known about their roles in other cancers. However, the proximity of the liver to the pancreas and the fact the pancreas and liver share common blood vessels and ducts make the pancreas a potential target for hepatitis viruses.
While this is the first study to examine whether exposure to HBV and HCV increases risk for pancreatic cancer, other research has indicated chronic HBV infection may impair pancreatic function and that HBV may replicate in the pancreas.
In this study, which began in 2000, 476 MD Anderson patients with early pancreatic cancer were identified. Additionally, 879 people without pancreatic cancer were matched with the patients by age, gender and race. All participants were interviewed for demographic and risk factors information.
Then researchers tested the blood of all participants for the presence of HCV and HBV antibodies, which indicate past exposure to HCV and HBV.
The prevalence of past exposure to HBV was significantly higher ( 7.6% ) in people with pancreatic cancer than in healthy people ( 3.2% ). However, exposure to HCV was not significantly different in the two groups.
In addition, the study confirmed previously reported risk associations of cigarette smoking, history of diabetes and a family history of pancreatic cancer.
People exposed to HBV may develop occult, or hidden, HBV infection. In these cases, the MD Anderson researchers say, there is a potential for reactivation of HBV during chemotherapy, the most common treatment for pancreatic cancer. Chemotherapy may suppress the immune system, leading to viral replication of the HBV, the researchers explained. ( Xagena )
Source: University of Texas MD Anderson Cancer Center, 2008