Aim: To study efficacy of thyroxine (TX) and potassium iodide (PI) in the treatment of benign nodular thyroid lesions (BNTL).
Material and methods: 118 patients with BNTL (colloid or colloid hypercellular as shown by thin needle aspiration biopsy, 'cold" or "warm" by scyntigraphy findings) were randomized into two groups: 59 patients were given thyroxin and the other 59 patients PI. The day dose of TX (75-150 mcg) was prescribed according to serum concentration of TTH trying to diminish it to 0.5 mIU/l and lower. PI dose was 200 mcg/day. Most of the patients were treated for 6 months. The response was evaluated with ultrasound investigation which measured thyroid volume, the size and number of the nodes in it before and in the end of therapy. The treatment was found effective if the dominant node decreased in size by 50% and more compared to pretreatment values.
Results: The size of the dominant node decreased by 50% and more in 14 of 59 (23.73%) patients on TX and in 20 of 59 (33.90%) patients on PI. Both TX and PI prevented growth of the dominant node size and number of the nodes in approximately 2/3 cases. TX was more effective in young patients (40.92 +/- 3.45 years) vs older ones (47.50 +/- 1.46 years, p = 0.047) and patients with colloid nodes. PI was more effective in patients with shorter node existence (3.93 +/- 1.21 and 8.59 +/- 1.74 months, p = 0.02). TX reduced thyroid volume from 20.42 +/- 1.69 to 15.18 +/- 1.30 ml (p = 0.001), PI--from 18.34 +/- 1.57 to 15.36 +/- 1.25 ml (p = 0.001).
Conclusion: TX and PI can inhibit or prevent the growth of thyroid benign nodes in approximately 2/3 patients especially in young patients with colloid nodes (TX) and in short existence of the node (PI).