Department of Diagnostic Imaging, Hokkaido University Graduate School of Medicine, Kita 15 Nishi 7, Kita-Ku, Sapporo, Hokkaido, 060-8638, Japan.
Department of Nuclear Medicine, Hokkaido University Hospital, Kita 14 Nishi 5, Kita-Ku, Sapporo, Hokkaido, 060-8648, Japan.
Ann Nucl Med. 2022 Nov;36(11):923-930. doi: 10.1007/s12149-022-01781-1. Epub 2022 Aug 16.
Radioactive iodine (RAI) therapy is a useful treatment for Graves' disease (GD). Most RAI sessions administer ≤ 500 MBq of iodine (I)-131. Sometimes patients require repeated RAI, often for longer periods of remission. We investigated the characteristics of patients for whom high dose (mostly 1110 MBq of I-131) RAI was effective as RAI therapy for GD.
We retrospectively analyzed the cases of 79 patients who underwent RAI for GD in a multicenter setting. We divided the patients into two groups based on the I-131 dose administered: the low dose (LD) group who received ≤ 500 MBq (n = 44) and the high dose (HD) group who received > 500 MBq (n = 35). The therapeutic effect was defined as achieving remission and reaching the point of participating in thyroid hormone replacement therapy within 1 year after RAI. We compared the LD and HD groups' remission rates and conducted a multivariate logistic regression analysis of predictive factors for remission. In a simulation, using the formula for predicting the probability of remission obtained from the analysis results, we estimated how much the remission rate would change if the I-131 dose is increased from 500 to 1110 MBq.
The mean ± standard deviation I-131 dose administered in the LD group was 480 ± 6 MBq, and that of the HD group was 1054 ± 265 MBq. Thirty-five patients (80%) in the LD group and 26 patients (74%) in the HD group achieved remission; this difference in the remission rate was not significant. The multivariate analysis results demonstrated that the absorbed dose and thyroid-stimulating antibody (TSAb) were independent predictors of remission. Seven patients (8.9%) showed an increased probability of remission from < 50% to > 50% when the higher RAI dose was applied (1110 MBq instead of 500 MBq). The thyroid volume and TSAb values in these patients were relatively large at 54.7 ± 34.2 mL and 1378.4 ± 586.3%, respectively.
Although the overall remission rate was not significantly different between the patients who received high- or low-dose I-131, treatment with high-dose RAI may improve the probability of remission in patients with a massive thyroid volume and/or high-TSAb Graves' disease.
放射性碘（RAI）治疗是 Graves 病（GD）的有效治疗方法。大多数 RAI 疗程给予≤500MBq 的碘（I）-131。有时患者需要重复 RAI，通常是为了更长时间的缓解。我们研究了那些接受高剂量（大多为 1110MBq I-131）RAI 作为 GD 的 RAI 治疗有效的患者的特征。
我们回顾性分析了在多中心环境中接受 RAI 治疗 GD 的 79 例患者的病例。我们根据给予的 I-131 剂量将患者分为两组：低剂量（LD）组，接受≤500MBq（n=44）；高剂量（HD）组，接受>500MBq（n=35）。治疗效果定义为在 RAI 后 1 年内达到缓解并达到开始甲状腺激素替代治疗的点。我们比较了 LD 和 HD 组的缓解率，并对缓解的预测因素进行了多变量逻辑回归分析。在模拟中，使用从分析结果中获得的预测缓解概率的公式，我们估计如果 I-131 剂量从 500 增加到 1110MBq，缓解率会发生怎样的变化。
LD 组的平均±标准偏差 I-131 剂量为 480±6MBq，HD 组的剂量为 1054±265MBq。LD 组 35 例（80%）患者和 HD 组 26 例（74%）患者达到缓解；缓解率无显著差异。多变量分析结果表明，吸收剂量和甲状腺刺激抗体（TSAb）是缓解的独立预测因素。当应用更高的 RAI 剂量（1110MBq 代替 500MBq）时，7 例（8.9%）患者的缓解概率从<50%增加到>50%。这些患者的甲状腺体积和 TSAb 值分别为 54.7±34.2mL 和 1378.4±586.3%，相对较大。
尽管接受高或低剂量 I-131 的患者总体缓解率无显著差异，但高剂量 RAI 治疗可能会提高甲状腺体积大且/或 TSAb 高的 Graves 病患者的缓解概率。
