Thyroglobulin levels and thyroglobulin/thyrotropin ratio could predict the success of the ablative/therapeutic 131I in the differentiated thyroid cancers. (2nd January 2017) - Trevizam, Paula Grasiele Carvalho
ABSTRACT: Background : Stimulated thyroglobulin (STg) levels in patients with differentiated thyroid carcinomas (DTCs) after total thyroidectomy (TT) and before radioactive iodine ( 131 I) ablation/therapy (RIT) are predictive of therapeutic success but can be influenced by the thyroid-stimulating hormone (TSH) level. Objectives : This study compared the reliability of the STg/TSH ratio and STg measurement in predicting the success of RIT. Methods : Sixty-three DTC patients submitted to TT were assessed retrospectively to compare the ability of STg level and the STg/TSH ratio to predict successful RIT. Results : In this study 48 (76.2%) patients had successful RIT. The successful and unsuccessful groups received different 131 I doses and had different STg levels and STg/TSH ratios. The STg and STg/TSH ratio cutoff values that predicted successful RIT were 4.41 ng/mL (sensitivity of 86.7% and specificity of 77%) and 0.093 (sensitivity of 80% and specificity of 79.2%), respectively. Age, STg level, STg/TSH ratio, and 131 I dose were associated with successful RIT, but after multivariate analysis only STg remained associated ( p < 0.05). Conclusion : In conclusion, our data suggest that the STg/TSH ratio and measurement of STg are equally reliable in predicting successful RIT in DTC patients.