Epidemiology

Hepatitis C virus infection associated with nonhepatic malignancies

Last Updated: 2005-02-28 14:35:03 -0400 (Reuters Health)

By Will Boggs, MD

NEW YORK (Reuters Health) - Patients infected with hepatitis C virus (HCV) face a higher risk of developing non-Hodgkin's lymphoma and other nonhepatic malignancies, according to Swedish researchers.

"In Swedish hepatitis C patients, the risk of Non-Hodgkin's lymphoma and multiple myeloma were about 2 times higher than in the general population, though the risk is still not very high," Dr. Ann-Sofi Duberg from Orebro University Hospital told Reuters Health. "I think this knowledge is useful for doctors."

After identifying a cluster of four cases of non-Hodgkin's lymphoma (NHL) in young, otherwise healthy hepatitis C patients, Dr. Duberg and colleagues used data from 27,150 HCV-infected Swedes to evaluate the association between HCV infection and NHL, multiple myeloma (MM), thyroid cancer, chronic lymphatic lymphoma (CLL), acute lymphatic leukemia (ALL), and Hodgkin's lymphoma. Their results appear in the March issue of Hepatology.

The risk of NHL was 99% higher and the risk of MM was 154% higher among patients with HCV infection than among the general population in Sweden, the authors report. The increased NHL risk was especially significant in the group infected for more than 15 years.

In contrast, the report indicates, the risks of CLL and thyroid cancer were not significantly increased in HCV-infected patients.

The paucity of patients with ALL or Hodgkin's lymphoma (only 1 each) precluded any conclusions about their association with HCV infection, the researchers note.

"The hypothesis that HCV is involved in lymphomagenesis is supported by the fact that HCV-RNA can be detected in hematopoietic cells, particularly in B cells and monocytes," the investigators explain. "However, there is no convincing evidence of viral replication in these cells, and it is unclear how the virus induces B-cell proliferation."

As for the clinical implications, "Be aware of these malignancies in patients with hepatitis C and other symptoms consistent with lymphoma or myeloma, and, on the other hand, think of hepatitis C in patients with non-Hodgkin's lymphoma or multiple myeloma," Dr. Duberg advised.

"As chronic hepatitis C may last for decades without symptoms, it is often diagnosed when the patient is on a medical examination for some other reason," she noted.

Hepatology 2005;41:652-659.