engleski

Thyroid remnant ablation in patients with papillary cancer : a comparison of low, moderate and high activities of radioiodine

The consensus about optimal activities of I-131 for thyroid remnant ablation has not yet been achieved. The aim of this study was to compare ablation rates obtained with different I-131 activities. The study included 466 patients divided into four groups according to I-131 activities given after total thyroidectomy for papillary thyroid cancer: group A (168 patients who received 888MBq/24 mCi), group B (125 patients who received 1480MBq/40 mCi), group C(65 patients who received 1850MBq/50 mCi), and group D(108 patients who received 4440MBq/120 mCi). Ablation outcome was assessed by whole- body scan in hypothyroid state 6– 9 months after ablation and finally 18– 21 months after the treatment. The rate of successful ablation was similar in the group of patients who received 24 and 40 mCi (75 and 71.2%, respectively). The higher rate of ablation was achieved in the groups treated with 50 and 120 mCi of radioiodine (87.69 and 90.74%, respectively). The ablation rates at the first follow-up examinations (59.5, 67.2, 73.9, 80.6%) were lower than at second control study (75.0, 71.2, 87.7, 90.7%) in all groups. Time required for thyroid remnant ablation seems to be >18 months. Our study indicates that activity of 50 mCi seems to be optimal to achieve a successful ablation rate (approximately 90%). Low I-131 activities are acceptable for lower risk patients because of satisfactory ablation rate (> 70%), lower expenses, and minimal radiation burden to patients as well as lower radiation exposure to clinical staff. The ablative use of high activities seems neither justified nor optimized.

I-131 activities ; remnant ablation ; thyroid cancer

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