Graves' disease and radioiodine therapy

Summary

Aim: This study was performed to analyse the impact of the choice of antithyroid drugs (ATD) on the outcome of ablative radioiodine therapy (RIT) in patients with Graves' disease. Patients, material, methods: A total of 571 consecutive patients were observed for 12 months after RIT between July 2001 and June 2004. Inclusion criteria were the confirmed diagnosis of Graves' disease, compensation of hyperthyroidism and withdrawal of ATD two days before preliminary radioiodine-testing and RIT. The intended dose of 250 Gy was calculated from the results of the radioiodine test and the therapeutically achieved dose was measured by serial uptake measurements. The end-point measure was thyroid function 12 months after RIT; success was defined as elimination of hyperthyroidism. The pretreatment ATD was retrospectively correlated with the results achieved. Results: Relief from hyperthyroidism was achieved in 96 % of patients. 472 patients were treated with carbimazole or methimazole (CMI) and 61 with propylthiouracil (PTU). 38 patients had no thyrostatic drugs (ND) prior to RIT. The success rate was equal in all groups (CMI 451/472; PTU 61/61; ND 37/38; p=0.22). Conclusion: Thyrostatic treatment with PTU achieves excellent results in ablative RIT, using an accurate dosimetric approach with an achieved post-therapeutic dose of more than 200 Gy.

Zusammenfassung

Ziel der Studie war die Überprüfung des Einflusses der thyreostatischen Medikation auf das Ergebnis der ablativen Radioiodtherapie (RIT) beim Morbus Basedow. Patienten, Material, Methoden: Im Zeitraum von Juli 2001 bis Juni 2004 konnten 571 Patienten 12 Monate nach Radioiodtherapie beobachtet werden. Einschlusskriterien waren ein gesicherter Morbus Basedow, die Rekompensation der Stoffwechsellage und das Absetzen der thyreostatischen Medikation zwei Tage vor dem Radioiodtest und der RIT. Die im Radioiodtest berechnete Zieldosis betrug 250 Gy. Peritherapeutisch wurde die tatsächlich an der Schilddrüse erreichte Dosis durch serielle Uptake-Messungen bestimmt. Endpunkt der Studie war die Schilddrüsenfunktion 12 Monaten nach RIT. Als Erfolg wurde die Beseitigung der Überfunktion gewertet. Die thyreostatische Medikation wurde retrospektiv mit dem Therapieergebnis verglichen. Ergebnisse: Das Therapieziel, die Beseitigung der Überfunktion wurde bei 96 % der Patienten erreicht. 472 Patienten waren mit Carbimazol oder Thiamazol (CMI) und 61 mit Propylthiouracil (PTU) vorbehandelt. 38 Patienten erhielten zum Zeitpunkt der RIT keine thyreostatischen Medikation (ND). Die Erfolgsrate war in allen Gruppen vergleichbar hoch (CMI 451/472; PTU 61/61; ND 37/38; p=0.22). Schlussfolgerung: Mit PTU vorbehandelte Patienten zeigen exzellente Therapieergebnisse bei ablativer RIT bei peritherapeutisch durchgeführter Dosimetrie und Erreichen einer posttherapeutischen Organdosis oberhalb von 200 Gy.

Keywords

Radioiodine therapy - Graves' disease - antithyroid drugs - thyrostatic medication - hyperthyroidism - dosimetry

Schlüsselwörter

Radioiodtherapie - Morbus Basedow - Thyreostase - Dosimetrie

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