The predictive role of 24h RAIU with respect to the outcome of low fixed dose radioiodine therapy in patients with diffuse toxic goiter

Abstract

radioactive iodine uptake (rAIU) is a test used to differentiate hyperthyroidism from thyroiditis and to calculate the radioiodine dose for treatment of Graves' disease. We aimed to evaluate the predictive role of 24h rAIU with respect to the outcome of radioiodine therapy in patients with diffuse toxic goiter (DTG). METHODs: case records of patients with DTG treated with radioactive iodine were reviewed retrospectively. Patients were divided into two groups based on 24h rAIU (normal range: 15% -35% at 24 h): the first group included patients with 24h rAIU values equal to or less than 50%, while the second group included patients with 24h rAIU values of over 50%. Gland size, duration of disease, treatment with antithyroid drugs (ATD) and its duration were the other factors considered. success of the first dose of 131 I was defined as a euthyroid or hypothyroid status at 12 months post-therapy without the need for additional radioiodine or ATD therapy. Data were analyzed with 95% power and 1% type I error (α=0.01). rEsULTs: six hundred thirty-three (633) consecutive patients with DTG were given a fixed-dose (5mci) of radioiodine between January 1987 and December 2006. One hundred seventy-five patients (175) had an rAIU ≤50% and 458 patients had an rAIU >50%. Firstdose success rate in the former group was 81.7% and in the second group 68.6% (p=0.001). The overall first-dose success was 72%. Multivariate analysis confirmed the significant role of 24h rAIU data to predict a successful outcome. cONcLUsION: A 24h rAIU value of ≤50% appears to be associated with a significantly better outcome compared to that of a 24h rAIU value of >50% in patients with DTG given as treatment a fixed dose of 185 MBq radioiodine.

Is There Any Need for Adjusting 131I Activity for the Treatment of High Turnover Graves’ Disease Compared to Normal Turnover Patients? Results from a Retrospective Cohort Study Validated by Propensity Score Analysis

“…In their research, DeGroot et al also concluded that larger thyroid volumes need to be treated with higher dosages of 131 I per unit volume [44], and this has been confirmed by other studies too [45]. In our previous study, Damle et al [46], studied the effect of RAIU on 131 I therapy outcomes where the authors administered 5 mCi 131 I (mean activity) for the treatment of GD and reported the first-dose success rate of 81.7% in patients with 24-h RAIU < 50% and 68.6% in the group with 24-h RAIU > 50% (p < 0.001).…”

Comparison of Fixed versus Calculated Activity of Radioiodine for the Treatment of Graves Disease in Adults

“…Studies have addressed the response to radioiodine therapy in relation to the radioiodine uptake and generally a high radioactive iodine uptake value is considered as a favorable factor for the success of radioiodine therapy [ 8 ]. However, studies by Damle et al [ 8 ] and Walter et al [ 9 ] have yielded conflicting results that showed an inverse correlation of pre-therapeutic iodine uptake level and therapeutic outcome. Standards regarding fixed doses were mainly based on studies done in iodine-replete countries, which may cause a lower radioactive iodine uptake value.…”

Radioiodine therapy in patients with Graves′ disease and the effects of prior carbimazole therapy

“…[1112] The good cure rates with low dose in our study population could be attributed due to relatively small diffused toxic goiters, probable relatively lesser iodine turnover, and persistent iodine-deficient state in a significant segment of Indian population despite universal iodization program implementation. Allahabadia et al ., reported that males are less likely to respond to a single dose of RAI[7] which is in line with study results in group B.…”