The thesis presents the results of a comprehensive clinical and laboratory investigation of patients suffering from nodular euthyroid goiter, their peculiarities in patients being operated on without relapse and with goiter relapse, which enabled to develop a new algorithm of therapeutic tactics based on the use of the gained prognostication scale assuming a substantiated choice concerning the volume of treatments of patients and prevention of goiter relapse.
Scientific novelty of the obtained results is that for the first time under clinical conditions a comprehensive comparative assessment of clinical data, thyroid status criteria, the findings of morphological, histochemical, cytochemical, immunohistochemical and immunocytochemical examinations was made in patients suffering from nodular euthyroid goiter and recurrent goiter. Concerning morphological characteristics, it was admitted that in the tissue of nodular goiter in its different variants in comparison with the thyroid gland without pathological changes the ratio between the parenchymal and stromal components of the goiter tissue changes statistically reliably (р<0,05) at the expense of the parenchymal specific volume. According to the immunohistochemical and immunocytochemical data a high activity of the new tissue formation processes in the tissue of nodular goiter was found which is most considerably marked with recurrent goiter. It is confirmed by the results of the studies concerning changes of Ki-67 protein index (р<0,05) in the thyroid cells which is indicative of an increased intensity of cellular proliferation. At the same time, the properties of proteins in these cells change which is manifested by the changes in the ratio between the amino groups and carboxyl groups in favor of the latter (р<0,05).
Scientific data concerning relations between the rate of growth of nodes, the process of relapse and changes of the thyroid homeostasis are specified. The rate of growth of nodes was found to possess a negative correlation dependence on the level of free triiodothyronine in the blood serum, ratio coefficient of free triiodothyronine to free thyroxin, total thyroid index (р<0,05). It demonstrates a positive correlation dependence on the level of thyroid-stimulating hormone, thyroid-stimulating hormone/ free triiodothyronine ratio, thyroid-stimulating hormone/ free thyroxin ratio, thyroglobulin level and titer of anti-thyroid antibodies (р<0,05). For the first time a method to predict probability of recurrent goiter development after surgery is suggested by means of a comprehensive assessment of clinical data, laboratory findings, results of morphological, cytochemical and immunocytochemical examinations of thyroid gland biopsy, which enable to substantially differentiate the groups of a low and high risk of recurrent goiter development. For the first time the algorithm of therapeutic tactics for patients with nodular forms of euthyroid goiter is suggested based on the application of the developed prognostication scale.
