Use of a dosimetry-based RAI protocol for treatment of benign hyperthyroidism optimises response while minimising exposure to ionising radiation.

BACKGROUND: The optimal treatment strategy for radioiodine (RAI) treatment protocols for benign hyperthyroidism remains elusive. Although individualised activities are recommended in European Law, many centres continue to provide fixed activities. Our institution implemented a dosimetry protocol in 2016 following years of fixed dosing which facilitates the calculation of individualised activities based on thyroid volume and radioiodine uptake. METHODS: This was a retrospective study comparing success rates using a dosimetry protocol targeting an absorbed dose of 150 Gy for Graves' disease (GD) and 125 Gy for Toxic Multinodular Goiter (TMNG) with fixed dosing (200MBq for GD and 400MBq for TMNG) among 204 patients with hyperthyroidism. Success was defined as a non-hyperthyroid state at 1 year for both disease states. Results were analysed for disease specific or patient specific modulators of response. RESULTS: This study included 204 patients; 74% (n = 151) received fixed activities and 26% (n = 53) of activities administered were calculated using dosimetry. A dosimetry-based protocol was successful in 80.5% of patients with GD and 100% of patients with TMNG. Differences in success rates and median activity administered between the fixed (204Mbq) and dosimetry (246MBq) cohort were not statistically significant (p = .64) however 44% of patients with GD and 70% of patients with TMNG received lower activities following treatment with dosimetry as opposed to fixed activities. Use of dosimetry resulted in successful treatment and reduced RAI exposure for 36% of patients with GD, 70% of patients with TMNG, and 44% of patients overall. CONCLUSION: This retrospective clinical study demonstrated that treatment with a dosimetry-based protocol for TMNG and GD achieved comparable success rates to fixed protocols while reducing RAI exposure for over a third of patients with GD and most patients with TMNG. This study also highlighted that RAI can successfully treat hyperthyroidism for some patients with activities lower than commonplace in clinical practise. No patient or disease specific modulators of treatment response were established in this study; however, the data supports a future prospective trial which further scrutinises the individual patient factors governing treatment response to RAI.

Prospective study to evaluate radioactive iodine of 20 mCi vs 10-15 mCi in Graves' disease.

OBJECTIVES: To assess whether increasing radioactive iodine dose can increase treatment efficacy in Graves' disease. METHODS: A prospective study was conducted, including 106 patients receiving 20 mCi (740 MBq) radioactive iodine (RAI), compared with a retrospective data, including 113 patients receiving 10-15 mCi (370-555 MBq) RAI. Remission and failure rates were evaluated at 6 months post-RAI. Statistical analysis was performed using logistic regression and Kaplan-Meier curves. RESULTS: Patients receiving 20 mCi RAI demonstrated a significantly higher remission rate compared to the 10-15 mCi group (82.1% vs 66.4%, p = 0.009). Median time to remission was shorter in the 20 mCI group (3 vs 4 months, p = 0.002). Hypothyroidism at 6 months was more prevalent in the 20 mCi group (67% vs 53%, p = 0.03). Larger thyroid size (> 60 g) was associated with treatment failure (p = 0.02). CONCLUSIONS: Higher dosage (20 mCi) RAI showed superior efficacy in achieving remission compared to lower dosages (10-15 mCi) in Graves' disease treatment.

Factors affecting timing of hypothyroidism following radioactive iodine therapy (RAIT) for patients with Graves' disease: A 12-month observational study.

BACKGROUND: This retrospective study analyzed factors influencing hypothyroidism development after radioactive iodine therapy for Graves' disease. PATIENTS AND METHODS: Three hundred and three patients with Graves' disease treated with radioactive iodine (RAI) from 2013 to 2022 at two Egyptian hospitals were included. Data collected included demographics, lab values, thyroid imaging, RAI doses, and outcomes. Patients were followed for ≥1 year to assess hypothyroidism onset. RESULTS: At the end of 1 year, around 79.5% of the individuals developed hypothyroidism while 12.5% continued to experience hyperthyroidism. The onset of hypothyroidism occurred earlier in those with thyroid volume (≤75.5 cm 3 ), lower thyroid weight (≤84.7 g), thyroid uptake (≤18.8%), and higher RAI dose/volume (≥0.1022 mCi/ml) ( P  < 0.001). Additionally, there was a correlation between anti-thyroid peroxidase (anti-TPO) antibodies and faster development of hypothyroidism compared to those who were negative for antibodies (2.9 vs 8.9 months, P  = 0.001). When considering factors in analysis it was found that anti-TPO antibodies were the only independent predictor, for developing hypothyroidism (hazard risk 30.47, P  < 0.001). Additionally, thyroid volume and uptake independently predicted successful treatment outcomes ( P  < 0.05). CONCLUSION: Positive anti-TPO antibodies strongly predict hypothyroidism risk after RAI therapy for Graves' disease. Smaller thyroid size, lower uptake, and higher RAI dose/volume correlate with earlier hypothyroidism onset but are less significant predictors than anti-TPO status. Findings can guide RAI therapy personalization to optimize outcomes.

Cancer Risk in Graves Disease with Radioactive 131I Treatment: A Nationwide Cohort Study.

Radioactive 131I (RAI) therapy has potential effects for the treatment of Graves disease (GD). However, whether RAI therapy for GD increases cancer risk remains controversial in medicine and public health. We aimed to investigate whether the risk of cancer increases in patients with GD receiving RAI therapy compared with those who did not. Methods: We used the Korean National Health Insurance Service's National Health Information Database from 2004 to 2020 and defined GD as prescribing antithyroid drugs, RAI, or thyroidectomy as a treatment for GD (International Classification of Diseases, 10th revision, E05 group). We investigated the hazard ratios (HRs) of overall and site-specific cancers associated with RAI in patients with GD. Subsequent cancer was defined as a primary malignancy treated at least 1 y after RAI therapy. Results: In total, 10,737 patients with GD who received RAI therapy (7,193 women, 67.0%; mean age, 43.7 ± 13.4 y) were matched to 53,003 patients with GD who had never received RAI treatment (35,471 women, 66.9%; mean age, 43.8 ± 13.2 y) in a 1:4-5 ratio by age, sex, and health checkup data. The median follow-up duration was 8.7 y (interquartile range, 5.2-12.1 y), and the median cumulative RAI dose was 555 MBq (interquartile range, 370-630 MBq) in the RAI therapy group. During 2004-2020, the overall subsequent cancer rates were 5.66 and 5.84 per 1,000 person-years in the RAI and non-RAI groups, respectively, with an unadjusted HR of 0.97 (95% CI, 0.88-1.06); this remained at 0.96 (95% CI, 0.83-1.10) after adjustment for multiple clinical confounding factors. For cancer subtypes, the risk of leukemia was significantly increased, with an HR of 2.39 (95% CI, 1.17-4.91). However, a loss of statistical significance was observed after adjusting for confounding factors, which may be attributed to the limited number of absolute events. Moreover, cancer-specific mortality was not different between the RAI and the non-RAI groups, with an adjusted HR of 0.99 (95% CI, 0.66-1.47). Conclusion: This study identified that the overall cancer risk in patients with GD who received RAI therapy compared with those who did not was not significant in Korea. Further long-term studies are needed to determine the risks and advantages of RAI therapy in patients with GD.

Radioactive Iodine Therapy of Graves' Disease in Patients Pretreated With Methimazole Without Radioiodine Uptake for Dose Estimation.

OBJECTIVE: To assess response predictors to radioactive iodine (RAI) therapy without using thyroid uptake for dose estimate in patients pretreated with methimazole. METHODS: Retrospective analysis was performed of patients with Graves' disease treated with RAI doses determined without using uptake studies. RESULTS: In 242 patients (median age, 41.9 years; 66.1% female), initial mean free thyroxine (FT4) level was 4.7 ng/dL with an estimated thyroid size of 49.15 g. Prior to RAI therapy, average methimazole dose was 22.7 mg/day. Mean RAI dose was 737.0 ±199.4 MBq (19.9 ± 5.4 mCi). Two hundred eight patients (85.9%) responded to RAI therapy; 185 (88.9%) became hypothyroid and 23 (11.1%) became euthyroid. The majority (90.4%) responded within 6 months of therapy with a quicker response (13.9 ± 8.3 vs 17.5 ± 13.5 weeks) for those treated with doses per gram of ≥14.8 MBq (0.4 mCi). Thirty-four nonresponders had a higher initial FT4 level and larger thyroid size with a lower RAI dose per gram of thyroid tissue. In multivariate analysis, the independent response predictor to therapy was dose per gram of thyroid tissue of ≥14.8 MBq (0.4 mCi) (hazard ratio, 3.18; 95% CI, 1.1-9.7). Doses per gram of 14.8 to 18.1 MBq (0.4-0.5 mCi) achieved maximal response rate without added advantage of higher doses. Thyroid size prior to RAI therapy, FT4 levels at diagnosis, and age were inversely related to response. CONCLUSION: RAI therapy for Graves' disease without uptake studies for dose estimates is an effective treatment method. In patients pretreated with methimazole, an RAI dose per gram of thyroid tissue of ≥14.8 MBq (0.4 mCi) showed high response rate. Prospective studies are needed to confirm the viability of this simplified and cost-effective approach.

Predictive factors for the outcome of radioiodine therapy in patients with benign thyroid diseases.

PURPOSE: Radioiodine therapy (RIT) of benign thyroid diseases is an established therapy. This study aimed to identify factors predictive for outcome in patients with non-toxic goiter (NTG), unifocal (UFA), multifocal (MUFA) or diffuse autonomy (DISA) and Graves' disease (GD). METHODS: Retrospective analysis of 205 patients with benign thyroid disease (54 NTG, 46 MUFA, 24 DISA, 26 UFA, 55 GD) who underwent RIT. Follow up time was 12 months for determining treatment outcome. RESULTS: The type of disease was predictive for volume reduction after 12 months (NTS 66%, DISA 67%, MUFA 58%, UFA 51%, GD 71%, p<0.001) and post-treatment hypothyroidism (NTS 48%, DISA 33%, MUFA 15%, UFA 15%, p=0.006). Initial volume, intra-therapeutic uptake and intra-therapeutic half-life were independent prognostic factors for volume reduction 12 months after RIT. In patients with NTG, UFA, MUFA, DISA post-treatment hypothyroidism was significantly correlated with extent of volume reduction 12 months after RIT, achieved dose, higher pre-therapeutic TSH values and younger age. Two different strategies for pre-therapeutic dosimetry used in MUFA showed no differences regarding the therapeutic outcome. In GD, effective half-life, initial volume and Graves' ophthalmopathy were predictive for treatment failure. CONCLUSION: Reduction of thyroid volume and the percentage of hypothyroid patients one year after RIT was primarily dependent on the type of disease. In MUFA and DISA we could identify volume reduction after 3 months as a reliable predictor for hypothyroidism while in patients with GD a short intra-therapeutic half-life, a large pre-therapeutic volume and active Graves' ophtalmopathy were relevant predictors for treatment failure suggesting an intensified follow-up scheme in these patients.

Factors predicting remission in hyperthyroid patients after low-dose I-131 therapy: 20 years retrospective study from a tertiary care hospital.

OBJECTIVE: To assess the therapeutic outcome and factors predicting remission in hyperthyroid patients treated with low-dose I-131 (radioactive iodine) from a tertiary care hospital in South India. METHODS: This 20-year single-institutional retrospective study was carried out on 3891 hyperthyroid adult patients. Only those patients with complete clinical records were audited. Selection criteria were based on patients with scintigraphic diagnosis of either Graves' disease (GD), toxic multinodular goitre (TMNG) or autonomous toxic nodule (ATN) and the records of those who received low-dose I-131 therapy (LDT) between March 2000 and 2020 at Amrita Institute, Cochin were analysed. SPSS 10 software was used for statistical analysis. RESULTS: The records of 3891 hyperthyroid predominantly female patients were analysed. 65% patients had GD, 33% had TMNG and 3% were ATN. High rates of remission as early as 12 weeks (in 61% patients) was observed with a single dose of LDT while on strict iodine-free diet for 3-4 weeks prior to LDT. Study reveals that those with lower free T4 (fT4), small goitre (thyroid volume < 25 cm3), < 15% thyroid trapping function, shorter time duration from onset of hyperthyroidism to LDT, and treatment-naïve patients were factors determining high remission rates. Mann Whitney U test and Chi-square test was used to correlate variables in the remission and relapse groups. We found a positive correlation between fT4, thyroid volume (r = 0.35, p < 0.01) and trapping function (r = 0.34, p < 0.01), which were independent of age, sex, body mass index and TSH levels in our study. CONCLUSION: High therapeutic outcome was observed with a single dose of LDT while on iodine-free diet. Remission with single dose of LDT occurred in 90% patients by 5th month. Of them 56% patients were treatment naive prior to LDT. LDT is thus a safe and effective therapy in hyperthyroid patients and can be recommended as a primary modality of management.

Quality of life and decision regret in patients with late-hypothyroidism after radioiodine treatment for Graves' disease.

OBJECTIVE: Patients with Graves' disease often engage in shared decision-making to select an individualised treatment regimen from multiple options. Radioactive iodine (RAI) is one of the treatment choices for their condition, aims to improve quality of life and well-being. Likewise, dissatisfaction with treatment outcomes can result in decision regret. We employed validated questionnaires to assess the prospective quality of life, decision regret and relative factors involved in decision-making of patients with late hypothyroidism after RAI therapy. METHODS: A questionnaire survey was conducted among patients in hypothyroidism status for more than 1 year after RAI therapy. Disease-specific and generic QoL were assessed using the short form of thyroid-related patient-reported outcome (ThyPRO-39) questionnaire. Patient satisfaction regarding their decision to undergo RAI was assessed using the Decision Regret Scale (DRS) and patients were asked about the importance of relative factors in decision-making. RESULTS: Of 254 patients who responded to the survey, the mean age of patients was 45.3 years (range: 18-78 years) and the median time from RAI therapy to survey was 4 years (range: 1-30 years). Patients' median and mean DRS score were 34.4 and 38.8 (range: 0-100), respectively. A total of 100 (39.4%) patients express absent-to-mild regret (score: 0-25), 154 (60.6%) patients express moderate-to-severe regret (score: >25). The mean score of the absent-to-mild regret group were significantly higher than those of the moderate-to-severe regret group on most ThyPRO-39 scales. A statistically significant positive correlation was observed between DRS score and most ThyPRO-39 scale score. There was a significant positive association between higher DRS score and longer time intervals after RAI treatment, a brief duration of hyperthyroidism, and the significance of long-time outpatient follow-up. More decision regret was negatively associated Iodine-free diet, ineffectiveness of ATD, fear of surgery. CONCLUSION: Impairment of quality of life was positively correlated with decision regret in patients with late-hypothyroidism after radioiodine therapy. Patients with insufficient information support before decision-making are more likely to have higher decision regret after treatment. Our findings suggest that health providers should fully communicate with patients and provide information support in multiple dimensions during the shared-decision-making process.

Effect of previous administration of potassium iodine and different durations of low iodine diets for radioiodine therapy on the treatment of Graves' disease in iodine-rich areas.

PURPOSE: To examine whether adherence to a low-iodine diet (LID) enhances the therapeutic efficacy of radioiodine therapy (RAI) in Graves' hyperthyroidism (GH) in iodine-rich areas. METHODS: We retrospectively evaluated 185 patients with GH from Aichi (n = 114) and Hokkaido (n = 71) Prefectures. Patients aged ≥ 18 years with GH who underwent RAI between December 2012 and March 2022 were divided into subgroups based on pretreatment with anti-thyroid drug (ATD) or potassium iodide (KI). Patients were followed up with LID from 18 days (group A) or 7 days (group H) before RAI to 3 days after RAI. The dose of radioactive iodine 131 (131I) was adjusted to deliver > 100 Gy to the thyroid. The associations between urinary iodine concentration on UIC2 vs. 24hRU and UIC2 vs. the 1-year RAI success rate (SR) were investigated. RESULTS: Compared with UIC1, UIC2 was significantly decreased in all subgroups (P < 0.01). An inverse correlation between UIC2 and 24hRU was observed in the four groups; however, the difference was insignificant. The SR in groups A and H was 85% and 89%, respectively. Univariate analysis revealed no association between UIC2 and SR in each group. Additionally, stratification of the 185 patients into quartiles using UIC2 yielded no significant differences in SR (p = 0.79). CONCLUSIONS: LID sufficiently reduced UIC in patients undergoing RAI. Although a lower UIC2 may increase 24hRU, it did not increase the success of RAI. The benefit of LID in enhancing the efficacy of RAI in GH treatment remains uncertain.

Radioactive iodine treatment for Graves' hyperthyroidism: incidence of Graves orbitopathy.

PURPOSE: There are limited recent data on the effect of radioactive iodine (RAI) for Graves' disease on Graves' orbitopathy (GO) development or reactivation. This audit investigates the GO incidence in patients with Graves' disease after RAI treatment, and explores risk factors present, and steroid prophylaxis use. METHODS: A retrospective audit of Graves' disease patients treated with RAI over a 5-year period. Data collected: smoking status, thyroid-stimulating hormone receptor antibody (TRAb) status, GO history, Graves' disease duration, eye features pre- and post-treatment, prophylactic corticosteroids, RAI dose given, post-RAI thyroid status, duration until hypothyroid. RESULTS: One hundred one patients were included, with a median Graves' disease duration 36 months. 34/101 (33.7%) were active/ex-smokers, 86/101 (85.1%) were TRAb-positive, 11/101 (10.9%) had a GO history; 32 (31.7%) had eye features present. Median RAI dose given was 596MBq. 8/101 (7.9%) patients received prophylactic corticosteroid; 89/101 (88.1%) achieved hypothyroid state in the year after RAI. GO developed in 5/101 (5.0%), of which 4/5 (80%) were de novo in high-risk individuals who did not receive steroids. One was a GO reactivation despite steroids. Two required intravenous steroids with/without orbital radiotherapy, one completed oral steroid taper; the remainder were treated conservatively. CONCLUSION: Our cohort had a lower GO incidence in patients with Graves' disease receiving RAI, with majority arising de novo . It is essential that all patients are assessed for Graves orbitopathy risk factors and counselled adequately prior to RAI. The decision to initiate steroids should be undertaken in a multi-disciplinary setting involving endocrinologists and ophthalmologists.

The influence of thionamides on intra-thyroidal uptake of 131I during radioiodine-131 treatment of Graves' disease.

Graves' disease is one of the most common causes of hyperthyroidism. Guideline recommendations advocate the intake of thionamides for at least 1 year. If hyperthyroidism persists, subsequent radioiodine-131 treatment (RIT) is a therapeutic option. Thionamides are known to influence intra-thyroidal bio-kinetics of iodine and should therefore be discontinued at least 3 days prior to RIT if possible. However, the required therapeutic activity has to be calculated individually by pre-therapeutic measurement of the uptake prior to RIT [radioiodine-131 uptake test (RIUT)] in Germany according to national guidelines. Therefore, the aim of this study was to quantify the influence of thionamides on intra-therapeutic uptake. A cohort of 829 patients with Graves' disease undergoing RIUT and RIT was analysed. Patients were subdivided into three groups. Group A: patients with carbimazole medication (n = 312), group B: patients with methimazole medication (n = 252) and group C: patients without thionamides (n = 265). Group A and B were further subdivided depending on the reduction of dosage of thionamides. In order to analyse the influence of thionamides, the variance of the determined individual extrapolated maximum intra-thyroidal uptake (EMU) between RIUT and RIT within the single groups and within the subgroups was statistically evaluated. When administering an equal dose of thionamides or no thionamides in RIUT and RIT (groups A1, B1 and C) no significant differences were detected when comparing EMU in RIT to EMU in RIUT (p > 0.05). In the subgroups A2-A4 (reduced dosage of carbimazole prior to RIT) EMU was significantly increased in RIT compared to RIUT [21% for a reduction of 0 to < 10 mg/d (A2), 39% for a reduction of 10-15 mg/d (A3) and 80% for a reduction of > 15 mg/d (A4)]. In the subgroups B2-B4 (reduced dosage of methimazole prior to RIT) EMU was as well significantly increased in RIT compared to RIUT [26% for a reduction of 0 to < 10 mg/d (B2), 36% for a reduction of 10-15 mg/d (B3) and 59% for a reduction of > 15 mg/d (B4)]. A significant dose-dependent increase of EMU in RIT compared to EMU in RIUT in patients discontinuing or reducing thionamides was detected. Therefore, thionamides should be discontinued at least 2 days prior to RIUT in order to achieve the designated target dose more precisely and to minimize radiation exposure of organs at risk.

[Clinical and immunological predictors of Graves' orbitopathy after radioiodine therapy of Graves' disease].

BACKGROUND: Data on the effect of 131I on the course of Graves' orbitopathy (GO) are contradictory. A number of studies indicate a deterioration in the course of GO against the background of RAIT, in other studies such a connection has not been established. Cytokines that regulate inflammation could potentially be biomarkers for assessing GO activity and predicting the course of GO after RAIT. AIM: The purpose of this study was to evaluate the dynamics of eye symptoms and analyze immunological parameters: cytokine TGF-ß1 and cytokine receptors: sTNFα-R1, sTNFα-R2, sIL-2R, sIL-6R over time after RAIT, as possible predictors of GO activation. MATERIALS AND METHODS: The study included 59 patients (118 orbits) with GD in the state of euthyroidism and subclinical hyperthyroidism and low active and inactive GO, aimed at conducting RAIT. Concentrations of cytokine TGF-ß1, sTNFα-RI and sTNFα-R2, sIL-2R, sIL-6R, TSH receptor antibodies (rTSH-Ab), free thyroxine (FT4) and free triiodothyronine (FT3), -thyroid-stimulating hormone (TSH) in the blood serum were determined. Ultrasound examination of the thyroid gland, multispiral computed tomography (MSCT)/magnetic resonance imaging (MRI) of the orbits was performed. The examination was carried out 3, 6, 12 months after the RAIT. RESULTS: The deterioration of the course of the GO (1-2 points according to CAS) was noted after 3 months. (32.5%) and to a lesser degree after 6 and 12 months (13.2% and 8.45%, respectively). Dynamics were not noted, approximately, in the same number of patients (40.5%, 41.5%, 45.8%, respectively). An improvement in the course of the GO was noted after 6 and 12 months (45.3, 45.8, respectively). After 3 and 6 months, the achievement of hypothyroidism and a significant increase in the level of rTSH-Ab were noted. In the analysis of cytokines and their receptors a significant decrease in the level of TGF-ß1 was noted after 3, 6 and 12 months. There was also a significant decrease in sTNF-R1 and sIL-2R at 3 and 6 months. The level of sTNFα-R2 significantly decreased 3 months after RAIT. The level of sIL-6R has not changed significantly. After 3 months in patients with positive dynamics of image intensification, the level of TGF-ß1 did not significantly change compared with the level before RAIT, in patients with worsening of the course of GO or without dynamics, the level of TGF-ß1 significantly decreased. After 6 months, there was the same trend, not reaching statistical significance. The IgG4 level and the IgG4/IgG ratio increased to 6 and 12 months, which corresponded to an increase in diplopia index. CONCLUSION: The main limiting factor in the conduct of RAIT is the activity of the autoimmune process in the orbits. Since patients with inactive (CAS 0-2) or low activity (CAS 3-4) GO were referred for RAIT, there was no pronounced activation of GO after RAIT. There was a slight deterioration in the course of GO by only 1-2 points according to CAS after 3 months. (32.5%) and to a lesser degree after 6 months (13.2%). In the study, it was found that the main predictors of the deterioration of the course of GO after RAIT are uncompensated hypothyroidism, a high level of rTSH-Ab and a decrease in the level of cytokine TGF-ß1.

Thyroid volume is the key predictor of hyperthyroidism remission after radioactive iodine therapy in pediatric patients.

Graves' disease (GD) is the leading cause of hyperthyroidism in pediatric patients. Radioactive iodine therapy (RAIT) is widely used to treat GD. However, it is still unclear exactly what determines the efficacy of RAIT in childhood and adolescence. The objective of our study was to reveal the most significant predictors of the efficacy of RAIT in pediatric GD patients. A single-center prospective observational exploratory study enrolled 144 pediatric patients (124 females and 20 males) between 8 and 18 years of age who underwent dosimetry-guided RAIT for GD for the first time. The estimated parameters included sex, age, thyroid volume, thyroid stimulating hormone (TSH), free triiodothyronine (FT3), free thyroxine (FT4), thyroid-stimulating hormone receptor antibodies (TRABs) at baseline and 12 months after RAIT, 10- to 20-min 99mTc thyroid uptake (%), maximum thyroid 131I uptake (%), specific 131I uptake (MBq/g), and therapeutic activity of 131I (MBq), which was limited to 1100 MBq. The Fisher's exact test, Mann-Whitney U-test, Wilcoxon signed-rank test, ROC analysis, and the Youden index were used for statistical analysis. Twelve months after RAIT, 119 patients (83%) successfully achieved remission, 6 patients (4%) had euthyroidism, and hyperthyroidism persisted in 19 patients (13%). Thyroid volume decreased from 17.6 [14.6; 24.1] to 9.3 [7.6; 13.3] mL 12 months after the treatment (p < 0.001). The main predictor that showed a statistically significant difference between the groups of patients who achieved and did not achieve remission of GD hyperthyroidism after RAIT was the initial thyroid volume. Using the Youden index, the optimal cut-off point for the initial thyroid volume at 45.4 mL was determined.     Conclusion: The dosimetry-guided RAIT in pediatric GD patients was 83% effective at 12 months after the treatment, and the initial thyroid volume of less than 45.4 mL was the most important predictor of RAIT success. Other predictors identified in our work included FT4 levels, TRABs levels, 99mTc-pertechnetate uptake, and specific 131I uptake. What is Known: •Radioiodine therapy is a common, effective, and safe treatment for pediatric patients with Graves' disease. What is New: •The initial thyroid volume in pediatric GD patients is an important predictor of achieving hypothyroidism following radioiodine therapy. If the thyroid volume is less than 45.4 ml, radioiodine therapy limited to 1100 MBq will be effective definitive treatment.

Efficacy of single-session radiofrequency ablation (RFA) in rendering euthyroidism for persistent/relapsed Graves' disease, a pilot study.

OBJECTIVES: Graves' disease (GD) is the most common cause of hyperthyroidism. Antithyroid drug (ATD) is often the first-line treatment but > 50% patients suffer a relapse when ATD is discontinued. Surgery or radioiodine remains the current options of definitive treatment in these patients. This pilot study examined the short-term efficacy of single-session thyroid radiofrequency ablation (RFA) as a novel definitive treatment for persistent/relapsed GD. METHODS: Consecutive patients with persistent/relapsed GD requiring ATD were considered. Those with a clear surgical indication, either thyroid lobe volume ≥ 20 mL; those who were pregnant or lactating; and those who had any severe medical conditions that would pose extra treatment risks were excluded. Eligible patients received ultrasound-guided RFA of the entire bulk of thyroid gland. Thyroid function tests were monitored bi-monthly. The primary outcome was disease remission rate, defined as a state of biochemical euthyroidism or hypothyroidism without ATD. Secondary outcomes were complication rates. RESULTS: Of the 68 patients considered, 15 (22.1%) patients were eligible. Most were females (93.3%). The median age was 37 (IQR 31-48) years old. The disease remission rates were 79.0% at 6 months and 73.3% at 12 months. Among the 4 patients who relapsed after RFA, three required less ATD dose than before RFA. RFA was well-tolerated in the ambulatory setting. There were no vocal cord palsy, skin burn, hematoma, or thyroid storm after RFA. CONCLUSIONS: In well-selected patients, single-session RFA of the thyroid gland may be a potential treatment for patients with persistent/relapsed GD. It is a safe and well-tolerated ambulatory procedure. KEY POINTS: • Radiofrequency ablation of the thyroid gland is an efficacious treatment for persistent/relapsed Graves' disease in well-selected patients. • Radiofrequency ablation of the thyroid gland for the treatment of persistent/relapsed Graves' disease is a safe and well-tolerated ambulatory procedure. • Radiofrequency ablation of the thyroid gland may be a potential alternative treatment for well-selected patients with persistent/relapsed GD who do not wish to undergo either thyroidectomy or radioactive iodine or continue antithyroid drugs.

Effect tracking of 131I treatment in Graves' hyperthyroidism patients within 1 year and analysis of the factors that may influence the cure.

OBJECTIVE: To observe the disease development and outcome of Graves' disease (GD) patients within 1 year after iodine-131 (131I) treatment, and analyze the factors affecting the treatment effect. SUBJECTS AND METHODS: Clinical data of 221 patients who received the first treatment with 131I in our department from June 2016 to October 2018 were retrospectively analyzed and they were followed up at 3 months, 6 months and 1 year after the treatment. According to the three follow-up records, the cure rate was calculated and the follow-up chart was drawn. The factors that may affect the clinical cure were analyzed according to the follow-up results after 1 year: Independent risk factors affecting the prognosis were screened out by Logistic regression analysis, and the effects of the above factors on the prognosis were further analyzed by Chi-square test, and the cure multiple relationship caused by the influencing factors was analyzed by Logistic regression analysis. RESULTS: The cure rate was 58.82% and the effective rate was 71.95%. At the 3-month follow-up, 11 patients (4.98%) presented complete response, 99 patients (44.80%) presented hypothyroidism, 93 patients (42.08%) presented partial response, and 18 patients (8.14%) presented no effect or recurrence. At 6 months, 18 cases (8.14%) had complete response, 90 cases (40.72%) had hypothyroidism, 59 cases (26.70%) had partial response, and 54 cases (24.43%) had no effect or recurrence. At 12 months, 36 cases (16.29%) had complete response, 94 cases (42.53%) had hypothyroidism, 29 cases (13.12%) had partial response, and 62 cases (28.05%) had no effect or recurrence. Thyroid weight and thyroid peroxidase antibody (TPOAb) were the influencing factors. Among all patients, patients with thyroid weight ≤28.70g were 4.25 times more likely to achieve clinical cure than patients with >28.70g [OR (95%CI):4.252 (2.383-7.588), P<0.01)], female patients with the thyroid weight ≤28.70g was 5.78 times than those with >28.70g [OR (95%CI): 5.776 (2.951-11.308), P<0.01]. In male, patients with TPOAb≤449.00IU/mL were 0.27 times more likely to achieve clinical cure than those with >449.00IU/mL [OR (95%CI): 0.274 (0.081-0.919), P<0.05]. CONCLUSION: Iodine-131 was an effective treatment to GD. Thyroid weight before treatment was the influencing factor for all patients and female patients, while TPOAb was the influencing factor for male patients.

Radioiodine uptake after monotherapy with potassium iodide in patients with Graves' disease.

The effect of potassium iodide (KI) on radioiodine uptake (RAIU) before radioisotope therapy in Graves' disease (GD) patients was investigated. A total of 82 patients who had been treated with KI monotherapy before 24-hour RAIU (24 h RAIU) were evaluated and 354 of those who had been treated with thiamazole (MMI) monotherapy were extracted from the 1,130 GD patients who were identified as having had appropriate iodine restriction based on urinary iodine excretion. Urinary iodine excretion (UIE) <200 µg/day was confirmed in all subjects. Propensity score-matching was performed to identify the difference in 24 h RAIU between the KI group and the MMI group. In addition, multiple regression analysis was performed to evaluate related to 24 h RAIU. Propensity score-matching resulted in 57 matched patients in each group. After matching, 24 h RAIU was still significantly lower in the KI group than in the MMI group (median 53% (interquartile range 47-61%) vs. 63% (56-66%); p = 0.001). In addition, KI monotherapy was weakly negatively correlated with 24 h RAIU, whereas the female sex and FT3 were very weakly positively correlated on multiple regression analysis. The results suggest that KI monotherapy likely suppressed 24 h RAIU more than MMI monotherapy in GD patients with appropriate iodine restriction, given the difference in the mechanism of hormone suppression.

Long-Term Follow-up of Graves Orbitopathy After Treatment With Short- or Long-Term Methimazole or Radioactive Iodine.

OBJECTIVE: The aim of this study was to compare long-term outcomes in terms of new onset or worsening of Graves orbitopathy (GO) in patients with Graves disease treated with different therapeutic modalities for hyperthyroidism. METHODS: A total of 1163 patients with Graves disease were enrolled in this study; 263 patients were treated with radioiodine and 808 patients received methimazole (MMI) therapy for a median of 18 months, of whom 178 patients continued MMI for a total of 96 months (long-term methimazole [LT-MMI]). The thyroid hormonal status and GO were evaluated regularly for a median of 159 months since enrollment. RESULTS: The rates of relapse, euthyroidism, and hypothyroidism at the end of follow-up were as follows: radioiodine treatment group: 16%, 22%, and 62%, respectively; short-term MMI group: 59%, 36%, and 5%, respectively; and LT-MMI group: 18%, 80%, and 2%, respectively. During the first 18 months of therapy, worsening of GO (11.5% vs 5.7%) and de novo development of GO (12.5% vs 9.8%) were significantly more frequent after radioiodine treatment (P <.004). Overall worsening and de novo development of GO from >18 to 234 months occurred in 26 (9.9%) patients in the radioiodine group and 8 (4.5%) patients in the LT-MMI group (P <.037). No case of worsening or new onset of GO was observed in patients treated with LT-MMI from >60 to 234 months of follow-up. CONCLUSION: Progression and development of GO were associated more with radioiodine treatment than with MMI treatment; GO may appear de novo or worsen years after radioiodine treatment but not after LT-MMI therapy.

A retrospective study of clinical features and prognosis of patients with Graves' disease and ophthalmopathy.

OBJECTIVE: To retrospectively investigate the clinical characteristics of patients with Graves' disease (GD) accompanied by ophthalmopathy (GO) and the prognosis of single 131I therapy. METHODS: In total, 665 patientswith Graves' disease were enrolled in this study, including 115 patients with GO and 550 patients without GO. On the one hand, the clinical characteristics of the two groups were recorded. On the other hand, the prognosis after more than 6 months of 131I therapy was divided into three groups: recovered, hypothyroidism and unhealed. RESULTS: Compared with GD-alone patients, GD patients with GO were younger, had a higher thyrotrophin receptor antibody (TRAb), heavier thyroid mass and higher dose of single 131I therapy (all P < 0.05). Furthermore, patients were younger in the clinical active score ≥3 group and had higher FT4 level in the mild GO group (all P < 0.05). Among these, age and TRAb were independent risk factors for GO in GD patients (P < 0.05). When age was <52.5 years and TRAb was >24.01 IU/L, GD patients were more likely to develop GO (P < 0.001). After at least 6 months of single 131I therapy, compared with GD-alone patients, the prognosis was poor in GD patients with GO (P < 0.05). CONCLUSION: Young GD patients with heavy thyroid mass and high TRAb are more likely to have GO. Younger GO patients are more likely to be active stage and the level of thyroid function was inversely correlated with the severity of GO. When the age and TRAb have exceeded the cutoff value, we should pay more attention to the occurrence of GO and shorten the follow-up interval appropriately. Patients with GD combined with GO have a poor prognosis.