| Povzetek: | A serum thyroid-stimulating hormone (TSH) level of > 30 mU/L, which is necessary for reliable testing and efficient radioiodine therapy in patients with differentiated thyroid carcinoma, may be achieved by a 4-6 week-L-thyroxin withdrawal or by application of recombinant human TSH (rh TSH). The purpose of our study was to test the efficacy of 131-I therapy (RIT) using recombinant human TSH (rhTSH) as an alternative in the patients with differentiated thyroid carcinoma (DTC) in whom endogenous TSH stimulation was not an option due to the poor patient’s physical condition during the hypothyroid state or due to the disease progression during L-thyroxin withdrawal. The study comprised 18 patients (13 females, 5 males, aged 37-79, median 73 years), with histologically proven DTC, in whom the primary diagnosis was established between 1993-2000. These patients underwent total or near-total thyroidectomy and received radioiodine ablation and 1-12 (median 5) RITs after L-thyroxin withdrawal, with a cumulative dose ranging 1.1 – 50.73 GBq (median 24.70 GBq). While on L-thyroxin after rhTSH administration (rhTSH RIT) they received altogether 46 RITs: four patients received one, 6 had 2, 3 had 3, 4 had four and 1 had 5 rhTSH–aided RITs. rhTSH (0.9 mg, i.m.), administered in two consecutive days, was followed by 131-I therapeutic dose (5.2-7.6 GBq) on the third day; 2-5 days later, post-therapeutic whole-body scan (PTWBS) was performed. The efficacy of rhTSH RIT was evaluated by thyroglobulin (Tg) measurement and/or follow-up radioiodine whole body scans (WBS) 2 to 12 months after rhTSH RIT. Results: Altogether 60 131-I-avid lesions were detected on PTWBS. Six to 12 months after the first rhTSH-aided RIT, partial response was achieved in 4/18 (22%). Stable disease was achieved in 3/18 patients (17%). In most patients (n=11, 61%), disease progressed despite rh TSH-aided RITs: a continuous progression was seen and Tg increased up to max 3500%, the Tg level changes being consistent with the results of post-RIT WBSs and the other follow-up modalities. The rhTSH was well-tolerated by most of the patients and side effects in all but one were mild. Conclusion: rhTSH-aided RIT proved to add some therapeutic benefit in at least 39% of our patients with metastatic DTC, who otherwise could not be efficiently treated with 131-I. The diversity of the other therapeutic approaches (previous RITs under endogenous TSH stimulation, external-beam radiotherapy, chemotherapy) applied within a relatively short time before rhTSH-aided RIT even in well-responding patients did not allow us to attribute the tumor and metabolic response just and only to RIT under rhTSH stimulation. |
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