Serum thyroglobulin determination in the follow-up of patients with differentiated thyroid carcinoma.

Thyroglobulin (Tg) is produced only by thyroid follicular cells. Following total thyroid ablation, it should be undetectable in serum and any detectable level then indicates the persistence or recurrence of neoplastic disease. This is the basis for the use of Tg as a postoperative tumor marker in the follow-up of thyroid cancer patients (1). The aim of follow-up is the early detection of persistent or recurrent disease, and this is made possible by the combined use of sensitive Tg measurement, neck ultrasound and a I total body scan (TBS) (2, 3). The results of Tg measurement are highly dependent on the method used. This paper therefore focuses ®rst on the methods used for the measurement of serum Tg level and then analyzes results obtained during the follow-up of patients with differentiated thyroid carcinoma, mainly based on experience at the Institut Gustave-Roussy, Villejuif, France.