engleski

Thyroid remnant ablation in papillary cancer

Despite many years of experience in thyroid cancer treatment the optimal dose of iodine-131 necessary for successful ablation is not established. The aim of the study was to compare the rate of ablation with different doses of radioiodine. The rate of ablation was compared in four groups of patients. Statistical differences were evaluated with Mann-Whitney U-test, Kruskal-Wallis test or Pearson’ s chi-square exact test and a P value less than 0.05 was considered to indicate statistical significance. 466 consecutive patients with papillary thyroid cancer (404 women, median age 47 years ; range 14-79 years), who have undergone total thyroidectomy were retrospectively studied. Ablative doses of I-131 were applied 4-6 weeks after the surgery. Patients were hypothyroid, with TSH more than 30 mIU/L. Patients were randomized into four groups according to 131 I administered activity, starting at 24 mCi (168 patients), then 40 mCi (125 patients), 50 mCi (65 patients), until 120 mCi (108 patients). The outcome of thyroid ablation was assessed by conventional 5 mCi whole body-scan, performed in hypothyroid state 6-9 months after ablation (first control study), and finally 12 months after (second control study). Successful ablation has been defined as the absence of residual thyroid uptake in thyroid bed. The rate of successful ablation was similar in the group of patients received 24 and 40 mCi (75% and 71.2% respectively). The higher rate of ablation (87.69% and 90.74%) was achieved in the groups treated with 50 and 120 mCi of radioiodine. In conclusion, our study indicates that a 50 mCi dose of radioiodine is a sufficient for a satisfactory thyroid ablation rate. Use of low effectively 24 and 40 mCi dose for initial ablation is justified by the convenience of administration, the lower expence and the lower whole-body radiation dose, and in our opinion this modality is convenient for group of patients with low risk of recurrent disease.

thyroid cancer; remnant ablation

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