Recombinant human thyrotropin preparation for adjuvant radioiodine treatment in children and adolescents with differentiated thyroid cancer

Aim: Although recombinant human thyrotropin (rhTSH) is widely used in treating differentiated thyroid cancer (DTC), almost all clinical investigation has been in adults. The aim of our retrospective study was to evaluate outcomes of adjuvant, rhTSH-aided radioiodine treatment in children/adolescents with DTC and to compare them to 131 I therapy during L-thyroxin withdrawal (THW). Methods: Patients with the diagnosis of DTC who were <= 18 years of age and had no signs of persistent disease at the time of 131 I treatment were included; 48 patients were treated after rhTSH (rhTSH group) and 82 after THW group. The median time of follow-up after therapy was 67 months and was longer in the THW group (99 vs 43 months, P<0.05). Results: On the day of I-131 administration, all but one patient had TSH levels above 25 mIU/ml. Peak TSH concentration was significantly higher in the rhTSH group (152 mu IU/ml vs 91 mu IU/ml). Similarly, the thyroglobulin concentration was higher in the rhTSH group (9.7 ng/ml vs 1.8 ng/ml). No side effects requiring medical intervention were recorded after rhTSH administration. The evaluation of disease outcomes during TSH stimulation (6-18 months after I-131 treatment) revealed equal rates of thyroid ablation (71%) in both groups. During subsequent follow-up, five patients showed recurrence (P>0.05). Conclusions: In children/adolescents, rhTSH-aided adjuvant radioiodine treatment is associated with rates of remnant ablation and short-term recurrence similar to THW. As this preparation has several advantages over THW, rhTSH may become the preferred method of TSH stimulation once studies of long-term outcomes show non-inferiority to THW in this age group.