Hepatitis C increases risk for non-Hodgkin's lymphoma

May 8 2007

Researchers in the U.S. have found that an infection with the hepatitis C virus increases the risk of a person developing non-Hodgkin's lymphoma.

Hepatitis C has a rather bad track record as it has already been linked to an increased risk of liver cancer and cirrhosis.

The hepatitis C virus (HCV) is estimated to affect about 1.6 percent of the U.S. population but it is more common among U.S. military veterans who use the Veterans Affairs (VA) medical system, and approximately five percent of veterans are infected with HCV.

In their study the researchers tracked 146,394 U.S. military veterans infected with the virus and 572,293 veterans who were not, between 1997 to 2004; all but 3 percent were men, most were white, and their average age was 52.

They found that HCV infection boosted the risk for non-Hodgkin's lymphoma by 20 percent to 30 percent.

Non-Hodgkin's lymphoma is cancer that starts in the lymphoid tissue that makes up the lymph nodes, spleen and other organs of the immune system; tumors develop from white blood cells and the cancer is more common in men than women.

The researchers also found that HCV infection raised by 300 percent the risk for a rare slow growing form of non-Hodgkin's lymphoma called Waldenstrom's macroglobulinemia.

The risk for cryoglobulinemia where abnormal levels of certain antibodies appear in the blood, also rose.

The researchers found there were 1,359 cases of non-Hodgkin lymphoma, 165 cases of Waldenstrpm macroglobulinemia, 551 cases of cryoglobulinemia and 320 cases of thyroid cancer.

HCV is spread through the body by the blood and spread from one person to another through the exchange of bodily fluids, for example, by sharing needles during injection drug use or by sexual contact; it was also spread via blood transfusions before 1990, when screening for the virus began.

Dr. Thomas Giordano of Baylor College of Medicine in Houston, the lead author of the study, says hepatitis C is a chronic infection, and as such it results in chronic stimulation of the immune system and these cancers are essentially cancers of the immune system.

The study found that infection with HCV preceded the development of these cancers and the increased risk was long-lasting.

HCV infection was also associated with an increased risk of nonmalignant plasma cell disorders.

The researchers suggest that HCV-infected individuals should be regularly screened in order to identify pre-cancer conditions which might then be treated to prevent the progression to lymphoma.

The findings are published in the Journal of the American Medical Association.