Thyrotropic function of hypophisys and i odine status in patients w ith thyroid cancer before I‑131 treatment

Abstract

The aim was to study thyrotropic function of pituitary gland and iodine status in patients with differentiated thyroid cancer a day before radioiodine therapy. Materials and methods. There were examined 110 patients with papillary and follicular thyroid cancer who were subjected to thyroidectomy in 2016-2017 years and radioiodine therapy was started in radiological department of the Institute. Study included 90 women aged 40Ѓ}12.34 years and 20 men aged 42.0Ѓ}11.0 years. One month prior to admission to the radiological department, suppressive therapy with L-thyroxine was canceled and a low-iodine diet was prescribed in patients. Clinical and laboratory examinations of patients were carried out directly before hospitalization. Results. TSH level in women was 79.0Ѓ}28.5 mIU/liter, in men — 83.0Ѓ}27.0 mIU/l at the time of study onset. Median thyroglobulin in whole group was 4.1 ng/ml, the Tg levels lower or equal 2 ng/ml were observed in 44.64% of patients and can be positively estimated regarding to the prognosis after radioiodine (I131) ablation. The Tg levels higher 2 ng/ml were observed in 55.35% patients, 17.86% of them had values higher 50 and 7.14% — higher 100 ng/ml. The median value of the urinary excretion level of iodine in the in the examined subjects was 92.87 mg/l, ranging from 9.34 to 851 μg / l (from 19.0 to 588.41 μg/24 h). More than 75% patients had ioduria lower 100 μg/l of creatinine, 20% of patients had an ideal result, iodine excretion level — lower than 30 mcg/L, a quarter part of patients probably did not adhere to necessary low iodine diet and represented ioduria higher than 100 μg/L of creatinine. All patients were taken I‑131, the average dose 3844.15Ѓ}227.89 MBq (from 2180 to 6000 MBq), depending on body mass and clinical diagnosis. Conclusion. The need for more strict adherence to low-iodine diet and I131 therapy after patient reach a satisfactory low-iodine status have been established.