Impact of regional metastases on prognosis of patients with thyroid carcinoma

Abstract

Background. According to many studies, the tumor size, the degree of extrathyroidal spread of the primary tumor to the organs and tissues of the neck and mediastinum, the degree of morphological differentiation of the tumor, as well as regional and distant metastasis are among the factors that worsen the prognosis of thyroid cancer treatment. The purpose is to study the regional metastasis indicators and the degree of their spread in patients with thyroid malignancies, and their influence on the prognosis of treatment depending on the spread of the primary tumor and the degree of morphological differentiation. Materials and methods. The study included 1,959 patients with a local primary tumor without invasion (group T1–3a), 171 patients with initial extrathyroidal spread of the primary tumor into the prethyroid muscles (group T3b), 132 patients with more widespread tumors, most often with the invasion into the trachea and/or larynx, internal jugular vein, esophagus, subcuta­neous fascia and tissue and skin, recurrent nerve (group T4a) and 38 patients with neglected disseminated primary tumors in the prevertebral fascia, carotid artery and/or with massive spread into the mediastinum (group T4b). Results. With the spread of the primary tumor, the number of patients with N1 regional metastases increased, along with percentage of more widespread N1b metastases in the lateral parts of the neck. Indicators of regional metastasis directly depend on the degree of spread of the primary tumor, which confirms it as the main factor affecting the prognosis of thyroid cancer treatment. In the group of non-invasive T1–3a tumors, the presence of N1 regio­nal metastases did not reliably affect the prognosis of treatment. In the group of more widespread tumors with initial T3b invasions, the presence of only widespread lateral regional N1b metastases worse­ned the prognosis. With the further spread of the primary tumor in the T4a group, the treatment prognosis worsened in patients, and equally for both N1a and N1b, in the group of neglected T4b tumors. Conclusions. The presence of regional metastases did not affect the prognosis of treatment, which was poor both in patients with and without regional metastases. Regional metastasis can be considered as a factor that worsens the treatment prognosis, but not as the main one, which remains the degree of spread of the primary tumor.