Antiviral therapy against chronic hepatitis C is associated with a reduced risk of oral cancer.

To identify the risk factors of oral cancer, we investigated the association between chronic hepatitis C (CHC) and oral cancer, and the development of oral cancer after anti-hepatitis C virus (HCV) therapy. We conducted a nationwide, population-based cohort study from 2004 to 2012 from the Taiwan National Health Insurance Research Database. CHC patients without anti-HCV therapy were matched with those non-HCV patients by age, sex and comorbidities. Moreover, CHC patients who underwent pegylated interferon and ribavirin (PegIFN/RBV) anti-HCV therapy were matched with CHC patients without anti-HCV therapy. A total of 100,058 patients were included in the HCV cohort and non-HCV cohorts, respectively. Their mean age was 59 years and 50% of these were male. CHC infection significantly increased the cumulative incidence of lichen planus and oral cancer. After adjustment for confounders and competing mortality, CHC infection significantly increased the risk of oral cancer (hazard ratio [HR]: 1.677, 95% confidence interval [CI]: 1.392-2.020, p < 0.001). Another 23,735 CHC patients without anti-HCV therapy were matched with 23,735 CHC patients in the treatment cohort. After adjustment for confounders and competing for mortality, the risk of oral cancer was significantly reduced in CHC patients receiving anti-HCV therapy (HR: 0.652, 95% CI: 0.479-0.887, p = 0.007). To minimize the inclusion of pre-existing unidentified oral cancer, we excluded oral cancer developed within the first year of CHC or anti-HCV therapy and found these associations remained statistically significant. In conclusion, CHC significantly increases the risk of oral cancer. Moreover, PegIFN/RBV antiviral therapy significantly reduces the risk of HCV-related oral cancer.