Multiparametric analysis of the treatment and follow-UP of patients with well differential thyroid cancer WHO received radioactive iodine therapy

The aim of our study is to investigate the relationship between prognostic risk classification and laboratory parameters and treatment response in well-differentiated thyroid cancer, and to examine different methods that can be applied in follow-up. Patients who applied to our department between 2008 and 2020, who underwent total thyroidectomy with the diagnosis of thyroid cancer, whose pathology results were compatible with papillary or follicular thyroid carcinoma, and who were treated with radioactive iodine were analyzed retrospectively. 173 patients who met the inclusion criteria were included in the study. Stimulated TSH, Tg, AntiTg values at the time of first admission and before treatment, the ratio of neutrophil and lymphocyte values in the hemogram checked before treatment, Tg and ATg values measured at the end of the mean 1 year, neck ultrasonography examinations, diagnostic 5 mCi I-131 whole body scanning (WBS) FDG PET/CT and other anatomical images were examined. The patients were classified as pathologically low, intermediate and high risk according to the 2015 ATA guidelines. Based on the 2015 ATA guideline, patients were classified into perfect complete response, biochemical incomplete response, structural incomplete response, and indeterminate response, according to their response to treatment at a mean of 1 year. In order to perform statistical analysis, patients in the biochemical incomplete response, structural incomplete response and indeterminate response groups were combined in a common group as patients who did not have a perfect complete response, due to the difference in the distribution of the number of patients between the groups. The relationship between the stimulated Tg levels before the treatment, the uptake of I-131 WBS after the treatment, the pathological risk groups, the neutrophil/lymphocyte ratio before the treatment, and the radioactive iodine dose were investigated. The excellent complete response rate of patients with low pathological risk was found to be significantly higher than those of intermediate and high risk patients. When the treatment response relationship between 100 mCi administered in the low pathological risk group and lower doses was evaluated, no statistically significant difference was found. When the pre-treatment stimulated Tg values were investigated between patients with and without involvement compatible with the metastatic focus, the stimulated Tg value was statistically significantly higher in patients with metastatic focus. When the relationship between the neutrophil lymphocyte ratio (N/L) and the treatment response groups of the patients was examined, it was observed that the N/L value was significantly lower in the perfect complete response group.