Circulating thyrotropin receptor messenger RNA for evaluation of thyroid nodules and surveillance of thyroid cancer in children

Purpose: The aim of this study was to determine the role of thyrotropin receptor messenger RNA as a novel blood test for evaluation of thyroid nodules and cancer in children. Methods: We reviewed thyroid disease management of patients younger than 18 years with thyrotropin receptor messenger RNA measurements identified from a prospective, institutional review board-approved registry during 2008 to 2010. Results: Thirty-nine thyrotropin receptor messenger RNA measurements were made in 21 female patients (12-17 years old; median, 16 years). Four patients with fine-needle aspiration only had benign thyroid cytology, and 3 of 4 had undetectable thyrotropin receptor messenger RNA. Seventeen patients underwent 22 thyroid operations. Preoperative thyrotropin receptor messenger RNA was measured in 9 patients: 3 of 4 with thyroid cancer had elevated levels and 3 of 5 with goiters undetectable. Postthyroidectomy surveillance (median, 16 months; range, 6-24) of 11 thyroid cancer patients (8 papillary, 3 follicular) showed that thyrotropin receptor messenger RNA was concordant with thyroglobulin in 14 (73%) of 19 measurements. In 3 (16%) of 19 measurements, thyrotropin receptor messenger RNA was the only blood test useful for disease assessment because of elevated antithyroglobulin antibodies. Overall, to predict thyroid cancer, thyrotropin receptor messenger RNA demonstrated 73% sensitivity, 82% specificity, 62% positive predictive value, 88% negative predictive value, and 79% accuracy. Conclusion: Thyrotropin receptor messenger RNA provides complementary evaluation to thyroglobulin and fine-needle aspiration for pediatric thyroid nodule management.