Incidental thyroid carcinoma in surgery-treated hyperthyroid patients with Graves’ disease: a systematic review and meta-analysis of cohort studies

BACKGROUND: The association between Graves’ disease (GD) and thyroid carcinoma remains controversial. This study aimed to investigate incidental thyroid carcinoma (ITC) in surgery-treated hyperthyroid patients with and without GD. MATERIALS AND METHODS: We searched PubMed and EMBASE for cohort studies investigating ITC in surgery-treated hyperthyroid patients without prediagnosed thyroid carcinoma in accordance with the Meta-Analysis of Observational Studies in Epidemiology guidelines. The last search was updated to January 23, 2018. All statistical tests were performed using Review Manager 5.3 and STATA version 12.0. RESULTS: Eleven cohort studies involving 10,743 GD and 3,336 non-GD patients were included. The pooled prevalence of ITC was 7.0% (95% confidence interval [CI] 4.5–9.6), and was comparable in surgery-treated GD and non-GD hyperthyroid patients (GD vs non-GD: pooled odds ratio [OR], 1.0; 95% CI: 0.68–1.46; P=0.98). In the subgroup analysis, toxic adenoma and toxic nodular goiter showed no difference when comparing with GD (pooled OR, 0.53; 95% CI: 0.21–1.36; P=0.18 and pooled OR, 1.01; 95% CI: 0.65–1.57; P=0.95, respectively). CONCLUSION: Our study demonstrated that GD was not associated with increased risk of ITC in surgery-treated hyperthyroid patients.