Efficiency of radioiodine therapy for thyroid cancer metastasizing to the mediastinum and lung

Abstract

Thyroid cancer (ТС) accounts for 0.4-2% of all malignancies. The lung is a more frequent site of distant metastases. The use of ¹³¹I is prominent in the treatment of distant TC metastases. The Department of Radiosurgical Treatment with Open Radionuclides, Medical Radiology Research Center, Russian Academy of Medical Sciences, made a retrospective analysis of the results of radioiodine therapy (RIT) in 126 adult patients with TC metastasizing to the lung and mediastinum. The treatment was performed after thyroidectomy when levothyroxine was discontinued. Repeated courses of RIT with an activity of 1-1.5 mCu of ¹³¹I per kg body weight were performed at an interval of 3-6 months. Analysis of the findings showed the high efficiency of RIT in patients with differentiated TC metastasizing to the lung and mediastinum. Five- and ten-year survival rates were 95.1 and 79.3%, respectively. A complete effect could be achieved in 66 (71.7%) patients. The high efficiency of RIT was observed in patients with TC with metastases to the mediastinum, with X-ray-negative and small-focal metastases to the lung, with the high accumulation of radiopharmaceuticals in the metastatic foci and in those with a thyroid-stimulating hormone level of more than 30mU/L.