Radioiodine ablation of post-surgical thyroid remnants after preparation with recombinant human TSH: why, how and when.

AIMS: The use of recombinant human TSH (rhTSH) represents one of the most exciting innovations in the field of differentiated thyroid cancer (DTC) management, but the use of rhTSH for radioiodine post-surgical thyroid remnant ablation is still controversial. The aim of this review is to provide the reader with an analysis of the literature regarding the use of rhTSH for the radioiodine ablation of post-surgical thyroid remnants.
METHODS: We performed a literature search of the most relevant papers in the PubMed database. FINDINGS AND
CONCLUSIONS: To date, five prospective studies have been published regarding this topic and there is strong evidence of the effectiveness of rhTSH, at least when high doses of 131I are used. Vice-versa, data regarding the outcome of ablation using low doses (30 mCi) are quite different in the studies published. So the problem of the amount of 131I to be administered and the influence of iodine intake is still open. In fact, the results of some studies suggest that 131I uptake could be particularly dependent on iodine intake during the euthyroid state and when low doses of 131I are used. This could be the reason for the reduced radioiodine uptake observed in other studies. However, also when rhTSH stimulation had produced a reduced iodine uptake, this was at least partially compensated for by an increased half-time in thyroid cells. So rhTSH stimulation appears to have pathophysiological bases which all lead to a powerful destructive effect by 131I on thyroid cells. All the data in the literature appear concordant that rhTSH is safe and associated to a good quality of life and the problem of costs appears negligible when compared to the benefits for the patient. In most cases, the use of rhTSH, for radioiodine ablation of post-surgical thyroid remnants can represent the best therapeutic option that we can offer to the patient.