Diferansiye tiroid kanseri tanılı I-131 ablasyon tedavisi verilen hastalarda hastaya ve hastalığa ait faktörlerin ablasyon başarısı üzerine etkileri

The effects of the factors related to the patient and the disease on the performance of ablation therapy in patients with differential thyroid cancer who have received I-131 ablation theraphy.Tarık ŞENGÖZ, Dokuz Eylül University, School of Medicine, Department of Nuclear Medicine, Izmir, Turkey,Aim and hypothesis: To investigate whether the factors related to the patient and the disease have any effect on the success of ablation therapy in patients with differential thyroid cancer who have received I-131 ablation therapy.Method: All the patients with differential thyroid cancer who had undergone total or near- total thyroidectomy referred for I-131 ablation therapy to the Nuclear Medicine Department between July 2007 and September 2009 were within the scope of this evaluation. The patients had at least the sixth month follow-up. Each patient was evaluated in terms of the following factors: age, gender, type of tumor, the presence of capsule and invasion, the size of tumor, the number of the tumors, the localization of the tumor, the invasion of thyroid capsule, lymph/vessels invasion, the presence of metastatic lymph nodes, the type of surgery, the preablation values of thyroglobulin (Tg), AntiTg, TSH, the images for the evaluation of metastatic diseases (thyroid and bone scan, neck and abdomen USG, thorax and brain CT), the administered dosage, postablation I-131 whole body scan (WBS), diagnostic I-131 WBS in the 6th month, neck USG in the 6th month, the values of Tg and AntiTg in the 6th month. The presence of residual thyroid activity on the 6th month diagnostic I-131 WBS image was accepted as the criterion for ablation performance. The patients with and without residual thyroid activity on I-131 WBS images were grouped as ablation negative and ablation positive, respectively. In the the ablation negative group I-131 WBS were re-evaluated independently by two experienced nuclear medicine physicians with the aim of confirming the presence of residual thyroid activity. Final decision was made by consensus. The variables related to the patient and the disease that might have effect on the success of ablation were grouped as quantitative and categorical variables. For statistic analysis, chi square test, Mann-Whitney U and for multivariant analysis, logistic regression test was used. The evaluation was made in SPSS 15.0.Results: 191 patients with differential thyroid cancer were evaluated in this study. The overall success rate of the first ablation therapy was 74.3%. The success rate of the first ablation therapy was 66% and 75% in metastatic group and non-metastatic group, respectively. The cumulative success rate of the ablation therapy was 93% in metastatic group and 80% in non-metastatic group. Despite significant correlation between pathologic lymph node number and the success of ablation was found (p=0.025), there was no significant correlation between the patients/disease related factors (age, gender, types of tumors, the number of the tumor focuses, the invasion of thyroid capsule, lymph and blood vessels et.) and the success of ablation therapy, except for .Discussion: There is a significant correlation between the number of the pathologic lymph node and the ablation therapy performance. However, it has been deemed that, this result can also be due to statistical error because of the limited sample size. There was no significant correlation between other patient/disease releated prognostic factors and the success of ablation therapy.Keywords; Differential thyroid cancer, I-131 ablation therapy, prognostic factors and ablation success.