PREOPERATIVE PROGNOSIS OF RADIOIODINE-RESISTANCE OF PAPILLARY THYROID CANCER

Aim. On the basis of detection of cytomorphological and immunocytochemical characteristics of thyrocytes of radioiodine - resistant metastases of papillary thyroid carcinoma to develop methods of their preoperative prediction and effectiveness of radioiodine therapy. Material and methods. Cytomorphological and imuno-cytochemical studies using monoclonal antibody against thyroid peroxidase, thyroglobulin, cytokeratins 7,8, antigen Ki-67, adhesion molecules of the epithelium were perfomed on the material of Fine Needle Aspiration Biopsy of 60 papillary thyroid carcinomas and their metastases detected in the postoperative period (70 – radioiodine - resistant metastases, 25 - radioiodine – sensitive metastases). Results. As a result of the conducted researches, the phenotypic heterogeneity of thyrocytes of radioiodine resistant metastases was revealed, in contrast to radioiodine-sensitive metastases, which is manifested by the presence of specific cell subpopulations and structures that are absent in radioiodine-sensitive metastases and primary papillary carcinomas. The correlation between the presence of cystic degeneration in punc-tuates of postoperative thyroid metastases and radioiodine re-sistance was revealed. Based on this, a method for preoperative prediction of radioiodine resistance of postoperative metastases has been developed. The statistically significant difference in the expression of thyroid peroxidase between radioiodine resistant and radioiodine-sensitive papillary thyroid carcinoma metastases is shown, on the basis of which the methods of preoperative prediction of radioiodine resistance of postoperative metastases is established. The tendency to increase the content of proliferating thyroiditis in punctates of recurrent papillary carcinoma metastases with repeated metastases is revealed. Conclusions: 1. For the first time the complex cytological and immunocytochemical researches of radioiodine-resistant metastases of papillary thyroid carcinoma were performed in comparison with radioiodine – sensitive metastases and primary papillary thyroid carcinoma and phenotypic features of radioio-dine-resistant metastases were discovered, on the basis of which methods of their preoperative prediction were developed. 2. As a result of the conducted studies, the correlation between the presence of cystic degeneration in the puncture material of postoperative metastases, and their radioiodine resistance. On the basis of which the method of preoperative prediction of the effectiveness of radioiodine therapy has been developed. 3. The sign of the phenotypic heterogeneity of the thyroid population, together with the low expression of the thyroid peroxidase, can be cytological factors of preoperative prediction of radioiodine resistance of papillary thyroid metastases, which arose in the postoperative period and the effectiveness of radio-iodine therapy. 4. A simple method for determining of thyroid peroxidase in punctuates of thyroid metastases detected in the postoperative period will allow for the prediction of the effectiveness of radioiodine therapy and discuss the implementation of neck dissection in patients with radioiodine resistance of papillary thyroid metastases and the feasibility of further radioiodine therapy in patients with radioiodine – sensitive metastase. This approach allows predict response of metastases on radioiodine therapy to choose proper therapeutic approach.