Endocrine Abstracts

Introduction: Postoperative thyroglobulin (TgPO) has a well established position as the prognostic factor for the follow-up of patients with differentiated thyroid cancer (DTC) after total thyroidectomy. However, the presence of thyroid remnants after surgery may diminish predictive value of TgPO.

The aim of the study is to evaluate prognostic value of stimulated postablative thyroglobulin level (TgPA) measured after 6–9 months after radioacitve iodine ablation, and its possible superiority to TgPO assessment.

Material: The study involved 1200 patients with DTC, treated in the Holycross Cancer Centre in Kielce in the years 2000–2013. Exclusion criteria were: patients with no recommendation for radioactive iodine therapy; positive thyroglobulin antibodies; initial distant metastases and patients who did not attend their appointments.

Methods: Both TgPO and stimulated TgPA levels were retrospectively studied. Considering further clinical follow-up and using ROC curve analysis, the TgPO and TgPA levels, which reliably predict favourable diagnosis, were assessed and compared.

Results: TgPO level ≤6.99 ng/ml with sensitivity of 75.7% and specificity of 94.7% enables to predict remission of the disease.

TgPA level ≤1.16 ng/ml under TSH stimulation induced by thyroid hormone withdrawal enables to predict remission of the disease with sensitivity of 91.1% and specificity of 94.7%.

TgPA level ≤1.24 ng/ml under rhTSH stimulation enables to predict remission of the disease with sensitivity of 95.4% and specificity of 95.0%.

Conclusions: No significant difference in clinical usefulness of determining TgPO and stimulated TgPA levels was revealed in terms of remission of the disease. However stimulated TgPA level ≤1.24 ng/ml with higher sensitivity predicts favourable prognosis.