Management of metastases to the thyroid gland

: The thyroid gland is rarely the site of metastatic disease because the vascularization, high oxygenation and high iodine of arterial blood content in the thyroid gland inhibit the growth of cancer cells. The incidence of the metastases depends on the type of primary tumor. Metastases to the thyroid gland account for 1.5–3% (approximately 2%) of all malignancies, with their autopsy-confirmed incidence rate ranging from 1.25% to 24.2%. Clinical material predominantly demonstrates metachronous metastases of clear cell carcinoma of the kidney, autopsy results show a predominance of metastases of the lung, colon and breast cancers. Metastases to the thyroid gland are most commonly unifocal metachronous tumors. Multifocal synchronous tumors are associated with a considerably poorer prognosis. The diagnostic method of choice is ultrasound-guided fine needle aspiration biopsy (FNAB) combined with immunohistochemically tests. Total thyroidectomy allows for a thorough evaluation of local tumor grade and is an important factor in oncological radicality of the surgical procedure. The role of multidisciplinary team is essential because balancing between the features of the primary tumor, status of the health (patient’s comorbidities), age of the patient, clinical grade, histological structure and profile of metastases at the time of diagnosis are important factors influencing individualized survival rate.