A new study has shown that evidence of past hepatitis B infection was twice as common in people with pancreatic cancer than in healthy controls. This study is the first to report an association between past exposure to the hepatitis B virus and pancreatic cancer, but researchers cautioned that more studies are necessary to evaluate the nature of the link.
"While our findings indicate that past exposure to hepatitis B is associated with the development of pancreatic cancer, more research is needed to determine whether this relationship is one of cause and effect," said lead author Manal M. Hassan, MD, PhD, assistant professor at the University of Texas M. D. Anderson Cancer Center. "If these findings can be confirmed by other studies, hepatitis B could be another risk factor for pancreatic cancer that is readily modifiable with treatment, and even preventable with a vaccine."
In this study, Hassan and her colleagues compared evidence of hepatitis B and C infection (as determined by blood tests assessing antibodies to these viruses) between 476 patients with pancreatic cancer and 879 matched healthy individuals. Evidence of past exposure to hepatitis B was found in 7.6 percent of patients with pancreatic cancer versus 3.2 percent of controls. The association between hepatitis B exposure and pancreatic cancer remained statistically significant even after controlling for other risk factors, such as smoking. People with both diabetes (an established risk factor for pancreatic cancer) and hepatitis B exposure had a seven-fold increase in pancreatic cancer risk, compared to controls. No association was observed between hepatitis C exposure and pancreatic cancer.
The authors noted that past studies have reported the presence of hepatitis B antigens in pancreatic fluids; others have identified impaired pancreatic function in people with chronic hepatitis B infection. These findings suggest that the hepatitis B virus may cause inflammation or DNA damage in the pancreas, which could increase cancer risk.
The researchers also indicated that there may be an increased risk of liver failure after chemotherapy treatment among patients with pancreatic cancer who have a history of hepatitis B infection. Dr. Hassan noted that if their findings are confirmed, oncologists may want to consider checking the hepatitis B status of their patients with pancreatic cancer before beginning chemotherapy.
Pancreatic cancer is estimated to strike 37,680 people in the U.S. in 2008, taking 34,290 lives. Because it is usually advanced by the time patients experience symptoms, it is very difficult to cure. Smoking and diabetes raise the risk of pancreatic cancer, but the disease also develops in people without these risk factors.
Two million people in the U.S. are currently living with chronic hepatitis B infection. While most new cases in previously healthy adults are cleared by the immune system within a few months, many people – especially those infected as newborns and children – develop chronic, lifelong infections.
Patrick J. Loehrer, Sr., MD, deputy director and medical director of the Indiana University Cancer Center, notes, “Pancreatic cancer is an aggressive disease that is very difficult to treat successfully. In large part, it is a result of the inability to prevent and diagnose early as treatment for advanced disease is palliative at best. If these data are confirmed by larger studies, they would highlight a new risk factor for this lethal cancer, a virus for which both treatment and a vaccine already exist. Whether this could then lead to an impact in the incidence of this disease requires further study."