Viral elimination reduces incidence of malignant lymphoma in patients with hepatitis C.

Purpose: A high prevalence of malignant lymphoma among patients with hepatitis C virus (HCV) infection has been reported. The aim of this retrospective study was to determine the incidence of malignant lymphoma and the relationship between malignant lymphoma and viral elimination in patients with HCV.
Method: We studied 501 consecutive HCV-infected patients who had never received interferon therapy and 2708 consecutive HCV-infected patients who received interferon therapy.
Results: In the non-interferon group, the cumulative rates of malignant lymphoma development were 0.6% at the 5th year, 2.3% at the 10th year, and 2.6% at the 15th year. The cumulative rates of malignant lymphoma development in interferon-treated patients with sustained virologic response were 0% at the 5th year, 0% at the 10th year, and 0% at the 15th year. The cumulative rates of malignant lymphoma development with persistent infection were 0.4% at the 5th year, 1.5% at the 10th year, and 2.6% at the 15th year. The malignant lymphoma development rate was higher in patients with persistent infection than in patients with sustained virologic response (P=.0159). The hazard ratio of lymphomagenesis in 1048 patients with sustained virologic response was significantly lower than in patients with persistent infection (hazard ratio: 0.13; P=.049).
Conclusion: Our retrospective study is the first to determine the annual incidence of malignant lymphoma among patients with HCV at 0.23%. Our results indicate that sustained virologic response induced by interferon therapy protects against the development of malignant lymphoma in patients with chronic HCV.