The Usefulness of Preoperative Thyroid-Stimulating Hormone for Predicting Differentiated Thyroid Microcarcinoma.

OBJECTIVE Thyroid-stimulating hormone (TSH) is a known thyroid growth factor, but the pathogenic role of TSH in thyroid tumorigenesis is controversial. The aim of this study is to examine the relationship between preoperative TSH and differentiated thyroid microcarcinoma (DTMC). DATA SOURCES We searched PubMed, EMBASE, Ovid, Web of Science, and the Cochrane Library from their inception to March 2015 and performed a systematic literature review of original studies. REVIEW METHODS Published studies that explored the relationship between preoperative TSH and DTMC were included for the review. We calculated odds ratio referring to different TSH concentrations between DTMC and control groups and used random effects model for the meta-analysis. RESULTS Nine eligible studies that included 6523 patients were identified. Meta-analysis revealed that DTMC was associated with high TSH concentration (odds ratio = 1.23, 95% confidence interval = 1.03-1.46, P = .001). Metaregression analysis indicated that the disparity of control groups was the possible factor resulting in heterogeneity among the studies. CONCLUSIONS The risk of DTMC increases significantly in parallel with TSH concentration. These results support the hypothesis that TSH is involved in tumorgenesis of differentiated thyroid cancer.