[Application of recombinant human TSH in the diagnostic protocol of differentiated thyroid carcinoma]

To describe the preliminary results of the application of this new technique in the diagnostic protocol in the management of differentiated thyroid cancer (DTC).

131I Whole body scan (WBS) was made under rhTSH stimulation in a group of 102 patients with DTC in follow-up, all treated by means of total thyroidectomy. The administration guideline was a dose of 0.9 mg of rhTSH (intramuscular) for two consecutive days, followed by oral activity of 185 MBq of 131I 24 hours after the last rhTSH injection, and later scintigraphic scan after 48 hours of the administration of 131I. Serum samples for TSH, thyroglobulin and antithyroglobulin antibodies determination were collected at 24 and 72 hours of the last administration of the rhTSH. Measures were made by means of immunometric assays.

TSH values at 24 hours after exogenous stimulation were 147.54 +/- 46.46 mIU/l. In 62 patients values of negative Tg were obtained (< 1 ng/ml), 50 of which presented negative WBS and 12 positive. 37 patients had positive Tg, 17 of whom presented negative WBS (confirming presence of disease in 7 patient by means of other imaging techniques) and 20 positive.

In every case, administration of rhTSH produced a significant increase of the TSH, making it possible to perform the usual controls of patient management (determination of serum Tg and WBS), similarly to the hormone withdrawal situation. There is no evidence of significant side effects, and its use makes it possible to avoid disadvantages derived from the hormonal withdrawal, maintaining a good quality of life in patients.