Embolization in combination with radioiodine therapy for bone metastases from differentiated thyroid carcinoma

BACKGROUND The outcome for patients with bone metastases from differentiate d thyroid carcinoma is worse compared to the overall prognosis of patients with differentiated thyroid carcinoma. The aim of this study is to evaluate the effect of embolization with concomitant radioiodine treatment on the s erum thyroglobulin (Tg) level, pain and neurological symptoms in patients w ith large bone metastases from differentiated thyroid carcinoma. PATIENTS AND METHODS Five symptomatic patients, who presented with a large unresectable bone metastasis of differentiated thyroid carcinoma were treat ed with radioiodine and embolization, The effect of this combined treatment was compared to the effect of radioiodine without embolization in a previo usly treated control group of 6 patients. Serum Tg levels, pain and neurolo gical symptoms were scored, Both groups were treated similarly with total t hyroidectomy followed by ablation with 5.55GBq I-131 and a second dose of 5 .55 GBq I-131 three months later, except for embolization in the embolizati on group, which took place between the 2 radioiodine treatments. RESULTS In the embolization group, serum Tg at the second I-131 therapy had decreased by 88.7% (median, range: 77.1-99.3%), which was significantly mo re compared to the decrease of serum Tg in the control group (18.6%, range: -4.7-95%, P<0.05). CT-scanning showed a median volume reduction of the met astasis after radioiodine treatment combined with embolization of 52.5% (ra nge: 39-80%). Both strategies resulted in a rapid relief of pain and neurol ogical symptoms. Embolization was not accompanied with severe complications . CONCLUSIONS This preliminary study suggests that embolization of bone metas tases of differentiated thyroid carcinoma in combination with radioiodine t reatment results in a significant initial reduction of serum Tg level compa red to radioiodine treatment alone. This suggests a beneficial reduction in tumour burden. In this patient category, embolization appears to be a safe and well tolerated procedure.