PurposeThis study was undertaken to summarize the published data and to provide more robust estimates regarding the issue of core needle biopsy (CNB) for discriminating thyroid nodules with indeterminate fine-needle aspiration (FNA) results.MethodsThe systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The sources comprised studies published through November 2017. Original articles that investigated CNB in indeterminate thyroid lesions were searched. A random-effects model was used for statistical pooling of the data. The I2 index was used to quantify the heterogeneity among the studies. The Egger test was carried out to evaluate the possible presence of significant publication bias. Quality assessment of the studies was performed according to QUADAS-2.ResultsA total of 205 articles were retrieved, seven were initially selected, and the data of five papers were ultimately pooled in a meta-analysis. The overall cancer rate was 34%. The rate of cancers correctly diagnosed by CNB was 83% (95% confidence interval [CI], 76 to 89), with neither heterogeneity (I2=25%) nor publication bias (Egger test, P=0.918). The rate of benign nodules correctly assessed by CNB was 84% (95% CI, 65 to 97), with significant heterogeneity (I2=93.4%) and publication bias (Egger test, P=0.016).ConclusionEvidence was found that CNB can correctly diagnose the majority of nodules previously read as indeterminate on FNA.