title: Ability of the rhTSH stimulation test to predict relapse in patients with differentiated thyroid carcinoma, after long-term follow-up.
abstract: The analysis of serum thyroglobulin (Tg) following thyroid-stimulating hormone (TSH) stimulation (sTg) has been recommended in the follow-up of differentiated thyroid carcinoma (DTC) patients, however, its routine use remains controversial. The aim of the current study was to evaluate the accuracy of sTg testing following recombinant human (rh) TSH stimulation in DTC patients, with a follow-up of 12.4 years. Retrospective studies were conducted of 125 DTC patients, who underwent rhTSH stimulation testing between 1999 and 2002. The exclusion criteria were: Patients with anti-Tg antibodies, Tg levels >1 ng/ml under TSH suppression and the absence of radioactive iodine (RAI) ablation therapy following surgery. In total, 49 patients were included in the study and all had been previously treated with total or near total thyroidectomy (with or without central neck dissection) and RAI, postoperatively. The Tg functional sensitivity was 1.0 ng/ml. The follow-up for patients was performed annually. During the median follow-up of 12.4 years after the rhTSH stimulation test, nine patients exhibited recurrence (18.4%). Of the nine patients, six exhibited sTg levels >2 ng/ml (positive result) and three exhibited levels <2 ng/ml (negative result). Relapse occurred at a mean of 5.9 years following the rhTSH stimulation test. The positive predictive value and negative predictive value (NPV) of positive sTg were 50 and 91.9%, respectively, with a sensitivity of 66.6% and a specificity of 85.0%. The rhTSH-stimulated Tg levels have a high NPV, allowing the identification of the patients who are free of the tumour. These results are consistent with the previously published data; however, to the best of our knowledge, this is the study with the longest follow-up duration after rhTSH stimulation.
authors: Department of Endocrinology, Portugese Institute of Oncology, Lisbon 1600-608, Portugal ; Department of Endocrinology, Armed Forces Hospital, Lisbon 1649-020, Portugal.
authors: Mafalda
authors: M
authors: Marcelino
authors: Department of Endocrinology, Portugese Institute of Oncology, Lisbon 1600-608, Portugal.
authors: Ana Filipa
authors: AF
authors: Lopes
authors: Laboratory of Endocrinology, Portugese Institute of Oncology, Lisbon 1600-608, Portugal.
authors: Deolinda
authors: D
authors: Madureira
authors: Department of Nuclear-Medicine, Portugese Institute of Oncology, Lisbon 1600-608, Portugal.
authors: Teresa C
authors: TC
authors: Ferreira
authors: Department of Endocrinology, Portugese Institute of Oncology, Lisbon 1600-608, Portugal.
authors: Edward
authors: E
authors: Limbert
authors: Department of Endocrinology, Portugese Institute of Oncology, Lisbon 1600-608, Portugal.
authors: Valeriano
authors: V
authors: Leite
keywords: accuracy; differentiated thyroid carcinoma; follow-up; recurrence; rhTSH test