RESUMO
Purpose: Several epidemiological studies investigated the relationship between hepatitis C virus [HCV] infection and risk of thyroid cancer, but the results were not consistent. A systematic review and meta-analysis was conducted to assess the impact of HCV infection on thyroid cancer risk
Methods: The literature was searched up to March 15, 2016 for case-control or cohort studies on the association between HCV infection and thyroid cancer risk. The summary relative risks [RR] and 95% confidence intervals [CI] were calculated
Results: Five studies [two case-control studies and three cohort studies] were included in the metaanalysis, with a total of 751,551 participants and 367 cases of thyroid cancer. Meta-analysis of those 5 studies found that there was no statistically significant association between HCV infection and thyroid cancer risk [summary RR = 2.09, 95%CI 0.78-5.64, p = 0.145; I[2] = 81.2%]. However, HCV infection was significantly associated with increased risk of thyroid cancer [summary RR = 2.86, 95%CI 1.63-5.03, p = 0.003; I[2] = 24.9%] after adjusting the heterogeneity
Conclusion: There is a possible association between HCV infection and increased risk of thyroid cancer, and more cohort studies are needed to validate the possible association