Hypothesis on effects of suppressive therapy in patients with papillary thyroid carcinoma

Abstract

The aim. To determine the effectiveness of the use of thyroid hormone suppressive therapy (TSH suppressive therapy) according to the data of the hospital register and to propose optimal conditions for its use. Material and methods. The study material was based on the results of observation of patients who underwent thyroidectomy at the SI «V.P. Komisarenko Institute of Endocrinology and Metabolism of the NAMS of Ukraine» regarding papillary thyroid carcinoma (PTC). The conditions for inclusion in the analysis group were the availability of data: TSH level, data from radioiodine therapy, sonographic examination and puncture biopsy, if such was performed. In total, there were 2781 such patients with a follow-up period of at least a year. The average follow-up period in the group of patients was 5.8 years, the maximum was 31 years. There were 576 patients using TSH suppressive therapy, 2205 without using suppression. There were 263 patients who experienced relapses during follow-up. Groups with and without TSH suppressive therapy were compared based on the occurrence of relapses. The analysis of the timing of the occurrence of relapses was carried out in separate periods from treatment (surgical or radioiodine) until the occurrence of relapse. Moreover, one patient could have several such periods. Comparison of terms was carried out using the Kaplan-Meier method by constructing the corresponding curves and calculating the statistical significance of the differences between them using the Log-Rank Test, Alternative Log-Rank Test, Wilcoxon Test and Tarone-Ware Test methods. Results. A statistically significant advantage in the presence of relapses among men was revealed, which coincides with the generally accepted fact that all thyroid carcinomas and, in particular, papillary carcinomas are more aggressive in them. No statistically significant difference was found in cases of TSH suppressive therapy, use. The distribution by age at the time of the primary surgery (children under
18 years of age and adults) and the presence of relapse revealed a statistically significant advantage for children, and a significant one, although the total number of patients under the age of 18 years in the study group was only 7.6%. It was shown that the total number of relapse cases in the groups with and without TSH suppressive therapy was not statistically different, but the time of relapse when analyzed by period was statistically significantly longer in the group using TSH suppressive therapy. Conclusions. In cases where TSH suppressive therapy is not effective, taking into account its negative consequences, including the tumor itself through the αVβ3 integrin, a switch to thyroxine replacement therapy can be considered. The authors propose a hypothesis that the use of TSH suppressive therapy only increases the time of recurrence manifestations, but does not affect the fact of their occurrence.