According to a report published in the Journal of the American Medical Association, research points to a new risk of Hepatitis C- the chance of contracting lymphoma.
The cancer of the immune system-lymphoma or non-Hodgkin's lymphoma is found to be 30 percent times higher in patients with hepatitis C, and for another cancer Waldenstrom's macroglobulinemia, the risk of a hepatitis C patient contracting it is 300 times higher.
More than 4 million Americans have hepatitis C, and about 26,000 new cases are diagnosed each year, according to the U.S. Centers for Disease Control and Prevention.
Lymphomas are cancers that originate in the lymphatic system, a part of the body's immune system. The two most common forms of lymphoma are Hodgkin's and non-Hodgkin's lymphoma. About 8,000 Americans develop Hodgkin's lymphoma and more than 56,000 develop non-Hodgkin's lymphoma each year, according to the Leukemia and Lymphoma Society.
Non-Hodgkin's lymphoma is cancer that originates in the lymphoid tissue that makes up the lymph nodes, spleen and other organs of the immune system, with tumors developing from white blood cells. It is more common in men than women.
Says study author Dr. Thomas Giordano, assistant professor of medicine at Baylor College of Medicine in Houston: "If I had hepatitis C, this would be one more piece of evidence that might make me consider treatment, though hepatitis C treatment can be difficult and is often unsuccessful. On the other hand, the risk of these cancers is so small; I wouldn't panic if wasn't getting treatment either. The overall risk is low."
According to Giordano ,chronic stimulation of the immune system caused by hepatitis C might be contributing to the development of certain lymphomas.
The study subjects recruited were 150,000 veterans from the Veteran Administration (Vietnam War). The scientists marked those with a diagnosis of hepatitis C, and then they matched by age and sex four healthy veterans for each person infected with hepatitis C. Nearly all of the veterans included in the study were male, and the average age was 52.
The researchers found that just fewer than 1,400 people included in the study developed non-Hodgkin's lymphoma and 165 developed Waldenstrom's lymphoma.
The risk of non-Hodgkin's lymphoma was 28 percent higher for those with hepatitis C, and the risk of Waldenstrom's was 276 percent higher.
While women only comprised 3 percent of the study population, Giordano believes the results would probably apply to women as well.
According to Marshall Lichtman, executive vice president for research and medical progress for the Leukemia & Lymphoma Society, the study could help scientists better understand the connection between infection and cancer. Several infectious agents — the Epstein-Barr virus, HIV and bacteria called Helicobacter pylori — are all associated with lymphoma.
Experts say that these organisms could cause cancer this way: Immune cells flock to the infection site, then make lots of copies of themselves to outnumber the viruses or bacteria that they want to kill. Most of the copies are normal, but a few have genetic mistakes, or mutations, that lead to cancer.
Worldwide, about one in five cancers are caused by infection. Doctors can prevent some of these cancers with vaccines, such as the hepatitis B vaccine, which can reduce the risk of liver cancer, or the new vaccine against human papillomavirus, which protects against most cervical cancers.
Giordano says that as there's no standard screening tool for lymphoma, there aren't any immediate practical implications from the findings. He said the findings may help researchers, and they may alert physicians to think of the possibility of lymphoma in their hepatitis C patients.