Response to antiviral therapy for chronic hepatitis C and risk of hepatocellular carcinoma occurrence in Japan: a systematic review and meta-analysis of observational studies

In Japan, hepatocellular carcinoma (HCC) is a leading cause of cancer mortality and hepatitis C virus infection is a major cause of HCC. We conducted a systematic review and meta-analysis of published studies evaluating patient response to antiviral therapy for chronic hepatitis C on the risk of HCC occurrence in Japan. Articles were searched using terms determined a priori through PubMed, screened by title and abstract, and selected by full-text assessment according to criteria determined a priori, including HCC occurrence in response to interferon (IFN)-based or IFN-free therapy, Japanese study, and 2 or more years of follow-up. We excluded studies on HCC recurrence. We calculated the pooled estimate of the crude incidence rate ratio with data from the selected studies using the person-years method with Poisson regression model and pooled estimate of the hazard ratio adjusted for potential confounders reported by the studies using a random effects model. A total of 26 studies were identified, all of which examined only IFN-based therapy as a result of the selection process. The pooled estimate (95% confidence interval [CI]) of 25 studies was 0.37 (0.33–0.43) for sustained virologic response (SVR) and 1.70 (1.61–1.80) for non-SVR for the HCC incidence rate per 100 person-years, and 0.22 (0.19–0.26) for the incidence rate ratio (SVR vs. non-SVR). The pooled estimate of the hazard ratio (95% CI) of HCC incidence adjusted for potential confounders of 8 studies was 0.25 (0.19–0.34). SVR to interferon therapy for chronic hepatitis C reduces the risk of HCC occurrence.