Serum thyroglobulin mesurement in the follow-up of patients treated for differentiated thyroid cancer

Determination of thyroglobulin (Tg)in serum represents a key element in the follow-up of patients treated for differentiated thyroid cancer (DTC). The sensitivity and the specificity of the assay strongly affects the clinical impact.Most of patients are disease-free after thyroidectomy and iodine ablation; 15% of them show over time persistent or recurrent disease; of these, 5% due to worsening of disease. This implies that the follow-up procedures should have a high negative predicitve value to reduce as possible the unnecessary diagnostic tools and a high positive predictive value to identify the few patients with persistent/recurrent disease. The recent international guidelines are based on thyroglobulin measurement after thyroid-stimulating hormone (TSH) stimulation. More recent studies suggest that follow up based on serial measurements of basal (i.e. unstimulated)Tg show a higher predictive value than the single measurement after stimulation. Large and multicenter studies are necessary to modify the current guidelines