Abstract

Papillary and follicular thyroid cancers, together termed differentiatedthyroid cancers (DTC), comprise the majority of thyroid carcinomas and have an optimal prognosis. MostDTCs appear as asymptomatic thyroid nodules. Fine-needle aspiration (FNA) cytology is the first diagnostictest for a thyroid nodule in a euthyroid patient. Surgery is the primary treatment for thyroid cancers.Most clinicians recommend near-total or total thyroidectomy, and then [sup]131[/sup]I ablation therapy, sinceits consequences are minimal and follow-up is facilitated. A total body scan (TBS) is performed 4 to7 days after [sup]131[/sup] I treatment. At a later stage, all patients should be treated with L-tiroxine so asto suppress TSH, and must undergo a periodic evaluation of TSH and thyroglobulin (Tg), the most sensitiveand specific marker of DTC. After 6-12 months, TBS with [sup]131[/sup]I is performed, a technique complementaryto serum Tg evaluation. For this technique, it is also necessary to have a high serum TSH concentration,obtained by withdrawing thyroxine therapy for 4 to 6 weeks. This standard method induces hypothyroidism.An alternative method to the withdrawal of thyroid hormones in the follow-up of DTC patients is to administerrecombinant human TSH (rh-TSH). After the dose of rhTSH, [sup]131[/sup]I is administered, and then TBS can beperformed 48-72 hours later. Currently, several authors have explored the possibility that rh-TSH-stimulatedTg levels may represent the only necessary test to differentiate patients with persistent disease fromdisease-free patients, without performing a diagnostic TBS.

Keywords: Carcinoma - therapy, Risk Factors, Thyroid Neoplasms - therapy