Antithyroid drugs as a factor influencing the outcome of radioiodine therapy in Graves' disease and toxic nodular goitre?

Abstract

There is controversy over the factors that may influence the outcome of radioiodine therapy for benign thyroid diseases. Antithyroid medication has been claimed to negatively influence the effectiveness of radioiodine therapy in Graves' disease. In a longitudinal study, we assessed the influence of sex, age, antithyroid drugs, target radiation dose, target mass, applied activity, delivered dose, interval between last meal and application, and TSH, FT3 and FT4 levels on the outcome of radioiodine therapy. One hundred and forty-four patients (111 female, 33 male) suffering from Graves' disease (GD) and 563 patients (434 female, 129 male) with toxic nodular goitre (TNG) were entered in the study and followed up until 8 months after therapy. Treatment was defined as successful when the TSH level was found to be normal or elevated. Ninety-eight GD patients and 418 TNG patients were successfully treated. Forward stepwise multiple regression analysis models retained only the target mass in GD and the applied activity in TNG as significantly associated with the outcome of therapy. The predictive value of all variables involved was extremely low in both disease groups. Whereas concomitant antithyroid medication had no influence in GD, it adversely influenced radioiodine therapy of TNG. This effect may be attributed to a radioiodine "steal phenomenon" induced by TSH-stimulated normal thyroid tissue, which causes overestimation of the uptake in toxic nodules.

Radiojodoterapia w chorobie Gravesa-Basedowa — czynniki wpływające na skuteczność leczenia w oparciu o analizę retrospektywną

“…This is because young people usually have larger goitres and higher blood concentrations of antithyroid antibodies (TRAb), which stimulate hyperthyroidism [10]. Our analysis shows, in accordance with what numerous other authors have found, that neither age (P < 0.094) nor gender (p < 0.378) have a significant influence on the outcomes of the therapy [11][12][13].…”

Outcome of radioiodine therapy without, on or 3 days off carbimazole: a prospective interventional three-group comparison

“…Thiamazoles and thiouracils have been found to reduce the success of radioiodine treatment in Graves' disease [3,5,[23][24][25][26]. In contrast, studies including both patients with Graves' disease and patients with toxic nodular goitre revealed propylthiouracil or multiple thyrostatics to have no effect in Graves' disease but an adverse influence in toxic nodular goitre [21,22]. However, the influence of simultaneous carbimazole medication alone on radioiodine therapy in toxic nodular goitre has not yet been investigated.…”

“…Anti-thyroid drugs are routinely used in the management of both Graves' disease and toxic nodular goitre [2,21,22]. There is controversy over whether their effect on radioiodine treatment is similar in both diseases.…”

Resumption of methimazole after 131I therapy of hyperthyroid diseases: effect on thyroid function and volume evaluated by a randomized clinical trial

“…Similarly to other recent studies (12,29,30) performed in order to evaluate the efficacy of 131 I therapy, we included patients with both autoimmune (Graves' disease) and non-autoimmune hyperthyroid diseases. Our finding of no radioprotection of methimazole, among patients with either Graves' disease or toxic nodular goitre, is in contrast to the findings by Körber et al (30).…”