Predicting outcomes and complications following radioiodine therapy in Graves' thyrotoxicosis

Predictive Performance of 2 Immunoassays in Patients with Graves Disease Undergoing Radioiodine Therapy: Prospective Study

Context

Radioactive iodine (RAI) treatment is a well-established successful treatment for Graves disease (GD) but causes an increment in autoantibodies, particularly TSH receptor antibodies.

Objective

To assess the performance and prognostic role of Immulite thyroid-stimulating immunoglobulin (TSI) and Elecsys thyrotropin receptor antibodies (TRAbs) immunoassays in patients with GD undergoing RAI therapy.

Methods

Clinical and laboratory data of 188 patients (156 GD and 32 toxic nodule goiter), undergoing RAI therapy between January 2018 and January 2022 were prospectively collected over 12 months. Refractoriness was defined as persistent or recurrent hyperthyroidism 6 months post-RAI treatment without levothyroxine. Statistical analysis included descriptive statistics, logistic regression, and generalized estimated equations.

Results

Patients had a mean age of 46.4 years, and 78.2% were women. RAI therapy was indicated in 94.2% due to uncontrolled hyperthyroidism or ATD therapy relapse (median of 35 months). Immulite TSI showed higher clinical sensitivity and accuracy (area under the curve [AUC]: 0.98, sensitivity 92.0%, accuracy 98.4%) than Elecsys TRAb (AUC: 0.97, sensitivity 82.1%, accuracy 91.2%). Successful treatment was achieved in 112 of 126 GD patients (89%). Thyroid volume, 2-hour iodine-131 uptake, free thyroxine and thyroxine levels, Elecsys TRAb, and Immulite TSI were significantly higher in the refractory group (P < 0.05), despite most patients receiving >300 Gy of RAI. Longitudinal thyrotropin evaluation predicted treatment response at 12 months (P = .01), whereas autoantibodies did not.

Conclusion

Refractoriness to RAI therapy was associated with higher levels of Immulite TSI and Elecsys TRAb prior to treatment. Although AUCs for both assays were equivalent, Immulite TSI demonstrated superior clinical sensitivity and accuracy. Despite distinct autoantibody patterns emerging post-RAI, longitudinal monitoring did not predict treatment response after 1 year but indicated persistently high concentrations.

Assessing a Novel Thyroid-Stimulating Antibody Bioassay as a Predictor of Radioactive Iodine Therapy Efficacy in Graves' Disease

OBJECTIVE

No studies have reported the use of the Biosensor TSAb assay (TSAb (Bio)) for predicting the therapeutic efficacy of radioactive iodine therapy (RAIT) for Graves' disease (GD). Therefore, we evaluated the usefulness of this novel thyroid-stimulating antibody (TSAb) bioassay kit, which uses a cyclic adenosine monophosphate (cAMP) biosensor, in predicting the therapeutic efficacy of RAIT in 20 patients with GD.

METHODS

We defined the RAIT outcome using two criteria: (i) thyroid weight reduction to <8 g and (ii) thyroid weight reduction to >80% at 12 months post-RAIT. For criteria (i) and (ii), regression analysis was performed for thyroid-stimulating hormone (TSH) receptor autoantibody (TRAb), TSAb (Bio), TSAb (Bio)/TRAb, I-131 absorbed dose/TSAb (Bio), and I-131 absorbed dose/(TSAb (Bio)/TRAb). After evaluating the significance of each factor, receiver operating characteristic (ROC) analysis was also performed.

RESULTS

Among the five aforementioned anti-TSH receptor antibody parameters, only I-131 absorbed dose/(TSAb (Bio)/TRAb) showed statistical significance in the multivariate analysis (p = 0.004 and p = 0.021 for each criterion). Although I-131 absorbed dose/(TSAb (Bio)/TRAb) correlated significantly with the thyroid weight (r = -0.54, p = 0.015), it did not correlate with thyroid weight reduction rates at 12 months post-RAIT. ROC analysis also demonstrated a good predictive value (area under the curve of approximately 0.8 with a cut-off value of 3.9) for I-131 absorbed dose/(TSAb (Bio)/TRAb) in predicting thyroid weight at 12 months post-RAIT.

CONCLUSIONS

TSAb (Bio) is a useful predictor of RAIT efficacy when evaluated as I-131 absorbed dose/(TSAb (Bio)/TRAb). This index was defined by dividing a factor that positively affects RAIT outcomes (I-131 absorbed dose) by a factor negatively affecting it (i.e., (TSAb (Bio)/TRAb)). The therapeutic efficacy of RAIT can be expected with an I-131 absorbed dose/(TSAb (Bio)/TRAb) value of ≥3.9. Adjusting the I-131 dosage based on this index may lead to more effective treatment outcomes.

Predictive Factors for the Efficacy of Radioactive Iodine Treatment of Graves' Disease: An Experience From 613 Chinese Patients

Objective: The utilization of radioactive iodine-131I (RAI) has long been established as a cost-effective and conventional treatment for managing Graves' disease (GD). However, the accurate prediction of the clinical response to RAI treatment remains difficult. The successful resolution of GD through RAI therapy is typically characterized by the induction of hypothyroidism or euthyroidism. Thus, the principal aim of this study was to identify plausible predictors of RAI efficacy in the treatment of GD. Methods: The clinical data of 613 GD patients, who underwent RAI treatment for the first time, were retrospectively analyzed, including age, gender, duration of hyperthyroidism, presence or absence of ocular signs, thyroid volume, thyroid weight, thyroid function (FT3, FT4, and TSH), radioactive iodine uptake (RAIU) at 2 h/6 h/24 h (2-h/6-h/24-h RAIU) prior to RAI treatment, the highest RAIU (RAIUmax), and administered activity of 131I and 131I activity per gram of thyroid tissue. Success of RAI treatment was defined as achieving hypothyroidism or euthyroidism for more than 1 year after the initial treatment. Univariate and multivariate logistics regression analyses were conducted to identify factors that influence the efficacy of RAI treatment for GD. And at last, based on the results of the multivariate logistic regression analysis, a nomogram model was established. Results: In this study, the success rate of RAI treatment for GD was 91.2% (559/613). Univariate analysis demonstrated that several factors, including age (p=0.005), thyroid volume (p=0.001), thyroid-stimulating hormone (TSH, p=0.042), ratio of RAIU at 6 h to 24 h (6-h/24-h RAIU, p=0.048), total 131I activity (p=0.026), and 131I activity per gram of thyroid tissue (p=0.001), were significantly associated with treatment outcome. Multivariate logistic regression analysis indicated thyroid volume and 131I activity per gram of thyroid tissue as significant independent predictors of radioactive iodine therapy (RIT) efficacy. The area under the ROC curve of the established nomogram model was 0.769 (95% confidence interval [CI]: 0.692-0.846), indicating that the model has good discriminatory ability. Conclusion: Calculated-dose RAI is effective in the treatment of GD. The smaller thyroid volume and the higher 131I activity per gram of thyroid tissue are predictors of RAI efficacy in the treatment of GD.

The Role of miRNA in Hyperthyroidism Induced by Excessive Iodine in Drinking Water

In recent years, iodine deficiency-related diseases have been effectively controlled; the prevalence of excessive iodine-induced thyroid diseases has increased, such as hyperthyroidism. However, there are still several controversial outcomes regarding the relationship between excessive iodine intakes and hyperthyroidism. MicroRNAs (miRNAs) extensively participate in the progression of thyroid diseases; nevertheless, the relationship and mechanism between iodine exposure and miRNAs have not been explored in hyperthyroidism patients. In this study, a total of 308 pairs of hyperthyroidism patients and healthy controls were enrolled in. Logistic regression analysis showed that level of water iodine >100 μg/L was an independent risk factor for hyperthyroidism. Compared with the healthy control, the serum thyroglobulin (Tg) content and levels of interferon-γ (IFN-γ), interleukin 6 (IL-6), and tumor necrosis factor-α (TNF-α) were significantly elevated in hyperthyroidism patients. Further, high-throughput miRNA sequencing was applied to find crucial miRNAs involved in the occurrence of hyperthyroidism related to excessive water iodine. Based on the fold change and Q value, miR-144-3p, miR-204-5p, miR-346, miR-23b-5p, and miR-193b-3p were selected for validation by qRT-PCR. Our results showed that miR-346 and miR-204-5p in the case group were significantly lower than those of the control group, and the similar results found under the level of water iodine >300 μg/L. Nonetheless, no significant difference was found at 10-100 μg/L level of water iodine. Furthermore, the ROC curve indicated that miR-346 and miR-204-5p had the ability to diagnose hyperthyroidism patients. Taken together, excessive water iodine may decrease the expression of miR-346 and miR-204-5p, which mediate the elevation of Tg and cytokines, ultimately making contribution to the development of hyperthyroidism.

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.

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.

Predictive markers for anti-inflammatory treatment response in thyroid eye disease

Anti-inflammatory treatment is the primary and vital therapeutic approach for active, moderate-to-severe thyroid eye disease (TED). Accurate pretreatment prediction of treatment response is of paramount importance for the prognosis of patients. However, relying solely on the clinical activity score asa determinant of activity has led to unsatisfactory treatment outcomes. In recent years, significant advancements have been made in identifying predictive markers for anti-inflammatory treatment response in TED, clinical markers, body fluid biomarkers and imaging biomarkers. Several clinical studies have developed prediction models based on these markers. However, there is still a lack of comprehensive elucidation or comparison between the different markers. Therefore, this review aims to provide a detailed analysis of the definition, characteristics, and application of predictive markers for anti-inflammatory treatment response in TED. Through detailed literature search, 26 articles applying anti-inflammatory treatment effect prediction with a total of 1948 TED patients were used for analysis and discussion. By gaining a better understanding of the current research on predictive markers, we can accelerate and guide the exploration of treatment prediction strategies, leading us towards an era of precise therapy for TED.

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.

Long-term thionamide antithyroid treatment of Graves' disease

Thionamide antithyroid drugs (ATD) are the treatment of choice for Graves' hyperthyroidism. The major drawback of ATD treatment for 1-2 years is the relapse of hyperthyroidism in about 50% of patients. Recently, it has been shown that ATD treatment for more than five years is accompanied by long-term remission in majority of patients without additional major side effects in both adults and children. Compared to radioactive iodine therapy, long-term ATD results in more favorable outcomes. This review summarizes the evidence on long-term ATD therapy regarding the remission rate of hyperthyroidism, efficacy and safety, indications and mode of therapy in patients with hyperthyroidism.

Time to Symptom Resolution After Total Thyroidectomy for Graves' Disease

INTRODUCTION

Total thyroidectomy (TT) has been shown to be a safe and effective treatment for Graves' disease. However, the time course for improvement of symptoms has not been defined.

METHODS

With an institutional review board approval, we prospectively gathered survey data of all patients (n = 79) undergoing TT for Graves' disease at a single institution from 2019 to 2021. After informed consent was obtained, patients completed surveys preoperatively and at 2 wk followed by monthly postoperative visits/phone calls. Patient demographics and survey results were collected and analyzed. Symptom recovery time was evaluated using Kaplan-Meier analysis.

RESULTS

A total of 50 patients completed the survey on postoperative follow-up (response rate 63%). Average age was 38 y (range 12-80 y) and 88% of patients were female. The most common preoperative symptoms were fatigue (90%) and heat/cold intolerance (88%). Tremor (median time to resolution: 1 wk; interquartile range [IQR] 1-3), diarrhea (median 1 wk [IQR 1-3]), and palpitations (median 1 wk [IQR 1-3]) resolved the most rapidly followed by eye symptoms (median 3 wk [IQR 1-6]), heat/cold intolerance (median 3 wk [IQR 3-30]), memory deficits (median 3 wk [IQR 1-undefined]), and fatigue (median: 3 wk [IQR 1-14]). There were no significant differences in time to resolution of symptoms by gender or age (less than versus 40 y and older). Those with uncontrolled Graves' had more severe symptoms but no difference in time to resolution from the euthyroid Graves' patients.

CONCLUSIONS

Many Graves' disease symptoms improve rapidly following TT, with a median time to improvement of less than 1 mo.

Total thyroidectomy is more cost-effective than radioactive iodine as an alternative to antithyroid medication for Graves' disease

BACKGROUND

Patients with Graves' disease treated with radioactive iodine report worse quality of life than those treated by thyroidectomy. However, radioactive iodine is often selected due to lower risk of complications and lower cost. The objective of this study was to estimate the cost-effectiveness of radioactive iodine versus total thyroidectomy for treatment of Graves' disease.

METHODS

A Markov decision-analytic model was created to simulate clinical outcomes and costs of medication-refractory Graves' disease treated with radioactive iodine or total thyroidectomy. Complication rates and utilities were derived from published data. Costs were extracted from national Medicare reimbursement rates. We conducted 1-way, 2-way, and probabilistic sensitivity analyses to identify factors that influence cost-effectiveness and reflect uncertainty in model parameters. The willingness-to-pay threshold was set at $100,000/quality-adjusted life-years.

RESULTS

Total thyroidectomy yielded 23.6 quality-adjusted life-years versus 20.9 quality-adjusted life-years for radioactive iodine. The incremental cost-effectiveness ratio was $2,982 per quality-adjusted life-years, indicating that surgery is highly cost-effective relative to radioactive iodine. Surgery was more cost effective than radioactive iodine in 88.2% of model simulations. Sensitivity analyses indicate that the model outcomes are driven predominantly by posttreatment quality of life, with contributing effects from rates of treatment complications and the impact of these complications on quality of life.

CONCLUSION

For patients with Graves' disease who either cannot tolerate or are refractory to antithyroid drugs, thyroidectomy is more cost-effective than radioactive iodine. Future research should validate reported differences in quality of life between these 2 treatment modalities.

Postradioiodine Graves' management: The PRAGMA study

OBJECTIVE

Thyroid status in the months following radioiodine (RI) treatment for Graves' disease can be unstable. Our objective was to quantify frequency of abnormal thyroid function post-RI and compare effectiveness of common management strategies.

DESIGN

Retrospective, multicentre and observational study.

PATIENTS

Adult patients with Graves' disease treated with RI with 12 months' follow-up.

MEASUREMENTS

Euthyroidism was defined as both serum thyrotropin (thyroid-stimulating hormone [TSH]) and free thyroxine (FT4) within their reference ranges or, when only one was available, it was within its reference range; hypothyroidism as TSH ≥ 10 mU/L, or subnormal FT4 regardless of TSH; hyperthyroidism as TSH below and FT4 above their reference ranges; dysthyroidism as the sum of hypo- and hyperthyroidism; subclinical hypothyroidism as normal FT4 and TSH between the upper limit of normal and <10 mU/L; and subclinical hyperthyroidism as low TSH and normal FT4.

RESULTS

Of 812 patients studied post-RI, hypothyroidism occurred in 80.7% and hyperthyroidism in 48.6% of patients. Three principal post-RI management strategies were employed: (a) antithyroid drugs alone, (b) levothyroxine alone, and (c) combination of the two. Differences among these were small. Adherence to national guidelines regarding monitoring thyroid function in the first 6 months was low (21.4%-28.7%). No negative outcomes (new-onset/exacerbation of Graves' orbitopathy, weight gain, and cardiovascular events) were associated with dysthyroidism. There were significant differences in demographics, clinical practice, and thyroid status postradioiodine between centres.

CONCLUSIONS

Dysthyroidism in the 12 months post-RI was common. Differences between post-RI strategies were small, suggesting these interventions alone are unlikely to address the high frequency of dysthyroidism.

TPO antibody status prior to first radioactive iodine therapy as a predictive parameter for hypothyroidism in Graves' disease

Objective

We investigated whether a positive thyroid peroxidase antibody (TPO Ab) status before radioactive iodine (RAI) therapy in patients with Graves' hyperthyroidism is a predictive factor for developing hypothyroidism post RAI.

Methods

We performed a retrospective study of patients with Graves' hyperthyroidism with known TPO Ab status, receiving the first administration of RAI. Patients from four thyroid outpatient centres in Belgium receiving their first RAI therapy between the years 2011 and 2019 were studied. Clinical, laboratory, imaging, and treatment data were recorded from medical charts. Hypothyroidism and cure (defined as combined hypo- and euthyroidism) were evaluated in period 1 (≥2 and ≤9 months, closest to 6 months post RAI) and period 2 (>9 months and ≤24 months post RAI, closest to 12 months post RAI).

Results

A total of 152 patients were included of which 105 (69%) were TPO Ab-positive. Compared to TPO Ab-negative patients, TPO Ab-positive patients were younger, had a larger thyroid gland, and had more previous episodes of hyperthyroidism. In period 1, 89% of the TPO Ab-positive group developed hypothyroidism and 72% in the TPO Ab-negative group (P = 0.007). In period 2, the observation was similar: 88% vs 72% (P = 0.019). In the multivariate logistic regression analysis, a positive TPO Ab status was associated with hypothyroidism in period 2 (adjusted OR: 4.78; 95% CI: 1.27-20.18; P = 0.024). In period 1, the aOR was 4.16 (95% CI: 1.0-18.83; P = 0.052).

Conclusion

A positive TPO Ab status in patients with Graves' hyperthyroidism receiving the first administration of RAI is associated with a higher risk of early hypothyroidism.

Clinical Outcomes of Repeated Radioactive Iodine Therapy for Graves' Disease

BACKGRUOUND

Radioactive iodine (RAI) therapy is a successful therapeutic modality for Graves' disease. However, RAI therapy can fail, and RAI therapy after antithyroid drugs (ATDs) has a lower remission rate. Therefore, many patients require repeated RAI therapy. This study investigated the clinical outcomes of repeated RAI therapy for Graves' disease.

METHODS

Patients who underwent RAI therapy as second-line therapy after failure of ATD treatment between 2001 and 2015 were reviewed. Remission was defined as hypothyroid or euthyroid status without ATD, and with or without levothyroxine at 12 months after RAI therapy.

RESULTS

The 1-year remission rate after 2nd RAI therapy (66%, 152/230) is significantly higher than that after 1st RAI therapy (48%, 393/815) or long-term ATD treatment after 1st RAI therapy failure (42%). The clinical response to 2nd RAI therapy was more rapid. The median time intervals from the 2nd RAI therapy to ATD discontinuation (1.3 months) and to the start of levothyroxine replacement (2.5 months) were significantly shorter than those for the 1st RAI therapy. A smaller goiter size, a longer time interval between the 1st and 2nd RAI therapies, and a longer ATD discontinuation period predicted remission after the 2nd RAI therapy. Finally, in 78 patients who failed the 2nd RAI therapy, the mean ATD dosage significantly reduced 5.1 mg over 12 months.

CONCLUSION

Repeated RAI therapy can be a good therapeutic option, especially in patients with smaller goiters and those who are more responsive to the 1st RAI therapy.

Hypothyroidism

Hypothyroidism is the common clinical condition of thyroid hormone deficiency and, if left untreated, can lead to serious adverse health effects on multiple organ systems, with the cardiovascular system as the most robustly studied target. Overt primary hypothyroidism is defined as elevated thyroid-stimulating hormone (TSH) concentration in combination with free thyroxine (fT₄) concentration below the reference range. Subclinical hypothyroidism, commonly considered an early sign of thyroid failure, is defined by elevated TSH concentrations but fT₄ concentrations within the reference range. Hypothyroidism is classified as primary, central or peripheral based on pathology in the thyroid, the pituitary or hypothalamus, or peripheral tissue, respectively. Acquired primary hypothyroidism is the most prevalent form and can be caused by severe iodine deficiency but is more frequently caused by chronic autoimmune thyroiditis in iodine-replete areas. The onset of hypothyroidism is insidious in most cases and symptoms may present relatively late in the disease process. There is a large variation in clinical presentation and the presence of hypothyroid symptoms, especially in pregnancy and in children. Levothyroxine (LT4) is the mainstay of treatment and is one of the most commonly prescribed drugs worldwide. After normalization of TSH and fT₄ concentrations, a considerable proportion of patients treated with LT4 continue to have persistent complaints, compromising quality of life. Further research is needed regarding the appropriateness of currently applied reference ranges and treatment thresholds, particularly in pregnancy, and the potential benefit of LT4/liothyronine combination therapy for thyroid-related symptom relief, patient satisfaction and long-term adverse effects.

[Definitive treatment of Graves' disease in children]

BACKGROUND

Hyperthyreoidism due to Graves' disease is a rare disorder in pediatric practice. There is 2 treatment options in Graves' disease: medical treatment and definitive treatment, including surgery and radioactive iodine. Each method has its advantages and disadvantages. If medical therapy is ineffective the choice between radical treatment method is raised: radioactive iodine or total thyroidectomy. In this research we analyze treatment outcomes in pediatric Graves' disease patients after different radical treatment methods.

AIM

Comparative analysis of radical treatment outcomes in pediatric patients with Graves' disease.

MATERIALS AND METHODS

Retrospective and prospective one-center research of 122 patients with Graves' disease after radical treatment (between 2016 and 2021)RESULTS: The mean age was 13.5±3,5 year at the moment of examination. Patients were divided into 2 groups due to the radical treatments method: 1 group (n=60) were children after surgical treatment, 2 group (n=62) - after radioactive iodine. The mean dose of medical treatment in these groups did not reliably differ (p=0,06), duration of the medical treatment was reliably longer in patients after radioactive iodine (p=0,024). Graves' orbitopathy was diagnosed in 58 patients (47,5%) and met equally often in both groups, but active stage of Graves' orbitopathy was diagnosed only in patients from the 1st group. Thyroid size was reliable bigger in patients from the 1st group (p=0,004), and thyroid gland nodes were diagnosed only in patients from 1st group (p=0,0007).

CONCLUSION

RI can be considered an effective and safe treatment for GD. The effectiveness of RI depends on the volume of the thyroid gland; according to the results of the constructed ROC curve, the risk of repeated RI is higher with a volume of more than 55 cm3. Also radioactive iodine is undesirable if there is signs of ophatalmopathy due to its possible deterioration. According to the results of the study hypoparathyroidism after surgical treatment was diagnosed in 20%, recurrent laryngeal nerve injury was diagnosed after surgical treatment in 5% of patients. In patients with identified nodular goiter according to the results of ultrasound, surgical treatment is preferable due to the impossibility of excluding thyroid cancer.

Management of Graves' hyperthyroidism: present and future

INTRODUCTION

Graves' disease (GD) is an autoimmune disorder due to loss of tolerance to the thyrotropin receptor (TSHR) and ultimately caused by stimulatory TSHR antibodies (TSHR-Ab). GD may be associated with extrathyroidal manifestations, mainly Graves' orbitopathy. Treatment of GD relies on antithyroid drugs (ATDs), radioactive iodine (RAI), thyroidectomy. The major ATD limitation is the high recurrence rate after treatment. The major drawback of RAI and thyroidectomy is the inevitable development of permanent hypothyroidism.

AREAS COVERED

Original articles, clinical trials, systematic reviews, meta-analyses from 1980 to 2021 were searched using the following terms: Graves' disease, management of Graves' disease, antithyroid drugs, radioactive iodine, thyroidectomy, Graves' orbitopathy, thyroid-eye disease.

EXPERT OPINION

ATDs are the first-line treatment worldwide, are overall safe and usually given for 18-24 months, long-term treatment may decrease relapses. RAI is safe, although associated with a low risk of GO progression, particularly in smokers. Thyroidectomy requires skilled and high-volume surgeons. Patients play a central role in the choice of treatment within a shared decision-making process. Results from targeted therapies acting on different steps of the autoimmune process, including iscalimab, ATX-GD-59, rituximab, blocking TSHR-Ab, small molecules acting as antagonists of the TSHR, are preliminary or preclinical, but promising in medium-to-long perspective.

Utility of outpatient fractionated radioiodine therapy for Graves disease involving a large goiter measuring more than 100 mL in volume

Contrary to large multinodular goiters, reports on ¹³¹I radioiodine therapy (RIT) for Graves disease (GD) involving a large goiter are scarce. We retrospectively reviewed a total of 71 consecutive patients (25 males, 46 females) with GD involving a large goiter (>100 mL) who had received RIT in our clinic. Patients with a history of thyroid surgery or with large thyroid nodules and those who had dropped out less than one year after the initial RIT session were excluded. A fixed ¹³¹I activity of 481 MBq was administered in most cases. RIT was repeated at intervals of 1-47 months, typically 3-6 months. The follow-up duration after the initial RIT session was 13-233 (median: 81) months. The thyroid volume was estimated using ultrasound. The number of ¹³¹I doses were 1 dose in 13 patients, 2 doses in 29, 3 doses in 17, 4 doses in 5, 5 doses in 5, 6 doses in 1, and 8 doses in 1. Sixty-six patients had remission from overt hyperthyroidism after RIT: overt hypothyroidism in 45 patients, subclinical hypothyroidism or euthyroidism in 13, and subclinical hyperthyroidism in 8. Their thyroid volume decreased from 101-481 (median: 126) mL to 1.4-37 (8.2) mL. Three patients still had overt hyperthyroidism under treatment with methimazole after one to three doses, and two dropped out less than six months after the third or sixth dose. Even in GD patients with a large goiter (>100 mL), repeated RIT with an activity of 481 MBq could sufficiently shrink goiters and remit overt hyperthyroidism.

Clinical efficacy of fixed-dose radioactive iodine for the treatment of hyperthyroidism at a single centre: our experience

BACKGROUND

Iodine-131 is an effective treatment for thyrotoxicosis. In 2019, National Institute for Clinical Excellence guidelines (UK) suggested offering radioactive iodine as first-line definitive treatment for adults with Graves' disease, toxic nodular and multinodular goitre unless it is unsuitable or anti-thyroid drugs are likely to achieve remission. The aim of this study was to evaluate the clinical outcome 1 year after using fixed-dose Iodine-131 for hyperthyroidism and time (months) to response.

METHODS

Electronic patient records were studied retrospectively for all patients who were treated with radioiodine therapy for hyperthyroidism between July 2017 and March 2020 at a district general hospital in the UK. Response to radioiodine therapy was initially assessed at 6 weeks and then at 3, 6, and 12 months by a dedicated thyroid nurse-led virtual follow-up.

RESULTS

We identified 67 patients with a mean age of 55.9 years (range 18-84); 48 (72%) females, 19 (28%) males. Of these, 57 (85%) patients were cured at 12 months (93.7% in non-Graves', 82.3% in Graves' group). Gender, diagnosis and pre-treatment disease interval were not significantly associated with treatment success. Non-Graves' patients had a significantly shorter time to discharge than Graves' patients receiving Iodine-131 (8 versus 10.3 months, p = 0.0174).

CONCLUSION

The results of the present study demonstrate that a single fixed dose of Iodine-131 therapy is highly effective and comparable to outcomes from calculated dose therapy in literature. We propose the routine use of scoring system to calculate risk of relapse for all newly diagnosed hyperthyroid patients to tailor treatment modality.

Predictive factors of a worse response to radioactive Iodine-I131 treatment in hyperthyroidism: outcome analysis in 424 patients. A single centre experience

PURPOSE

Aim of our study was to search for variables associated with worse outcomes in patients treated with radioactive iodine (RAI) for hyperthyroidism by a dosimetric-based approach.

METHODS

Four hundred twenty-four patients with hyperthyroidism related to Toxic Multinodular Goiter (TMG; n = 213), Grave's disease (GD; n = 150) and toxic adenoma (TA; n = 61) treated with RAI between 2000 and 2018 and with at least 12 months follow-up were retrospectively evaluated. Association between outcomes (response vs. no response) at 6 and 12 months and baseline TSH values, anti-thyroid drugs (ATD) duration and posology, RAI absorbed dose and dimensional reduction of target mass at ultrasound was evaluated by Mann-Whitney test. Risk factors for response vs. no-response were analysed by binary logistic regression model.

RESULTS

Overall response rate was 78.7 and 83% at 6 and 12 months, respectively. Both at 6 and 12 months higher TSH baseline values (p < 0.001), lower ATD duration (p = 0.004 and p = 0.043), lower ATD posology (p = 0.014 and p = 0.005), and lower dose to target (D_T) (327 vs. 373 Gy, p = 0.003) were associated to response. Longer ATD duration and higher ATD posology were independent risk factors for no response at 6 and 12 months in GD and TMG, with no response at 6 months in TA subgroups.

CONCLUSIONS

Low TSH levels, longer duration and higher posology of ATD were associated with worse response to RAI. These data confirm that RAI therapy should be considered earlier in patients' management to allow better outcome and avoid ATD toxicity.

Predictive factors of radioiodine therapy failure in Graves' Disease: A meta-analysis

BACKGROUND

I-131 therapy is a common treatment modality for adults with Graves' Disease (GD). Utilizing meta-analysis, we examined patient specific factors that predict I-131 therapy failure.

METHODS

Literature search followed PRISMA. Comprehensive Meta-analysis (version 3.0) was used. Mantel-Haenszel test with accompanying risk ratio and confidence intervals evaluated categorical variables. Continuous data was analyzed using inverse variance testing yielding mean difference or standardized mean difference. Decision tree algorithms identified variables of high discriminative performance.

RESULTS

4822 collective patients across 18 studies were included. Male sex (RR = 1.23, 95%CI = 1.08-1.41, p = 0.002), I-131 therapy 6 months after GD diagnosis (RR = 2.10, 95%CI = 1.45-3.04, p < 0.001) and history of anti-thyroid drugs (RR = 2.05, 95%CI = 1.49-2.81, p < 0.001) increased the risk of I-131 therapy failure. Elevated free thyroxine, 24-h radioactive iodine uptake scan ≥60.26% and thyroid volume ≥35.77 mL were also associated with failure.

CONCLUSION

Patient characteristics can predict the likelihood of I-131 therapy failure in GD. Definitive surgical treatment may be a reasonable option for those patients.

Success rate of radioactive iodine treatment for children and adolescent with hyperthyroidism

PURPOSE

To assess the success rate of first dose radioiodine for treatment of hyperthyroidism in children and adolescent.

METHODS

This is a retrospective data analysis of children and adolescent with hyperthyroidism who received radioiodine (RAI) therapy from January 2013 to December 2017. Age, gender, family history of hyperthyroidism, duration of anti-thyriod drugs (ATDs) treatment, rapid turnover status, 2 h and 24 h I-131 radioiodine uptake (RAIU), thyroid volume, and treatment dose were also analyzed. The goal of RAI therapy was to achieve hypothyroidism within 3-6 months after treatment. Treatment result was evaluated at 6 months after treatment and divided into 2 groups: treatment success (hypothyroid and euthyroid) and treatment failure (hyperthyroid). The same parameters were compared between both groups.

RESULTS

32 hyperthyroid patients, 26 female with mean age at treatment of 13.84 ± 1.83 years. All patients had prior treatment with ATDs, with a median treatment duration of 32.5 months (range 2-108). The median estimated thyroid gland size was 24.62 g, range 9.29-72.8. RAI doses ranged from 4.1 to 29.9 mCi (median dose = 7.54 mCi). Significant difference in 24-h I-131 uptake and RI status was demonstrated. Successful treatment rate after single dose of therapeutic I-131 was 65.63%.

CONCLUSION

With the I-131 dose of 220 μCi/g of thyroid tissue, successful treatment rate after single dose of therapeutic I-131 was 65.63%. RAI therapy with I-131 dose of 250-400 μCi/g of thyroid tissue might be suitable in patients with medical failure from ATDs. Possible role of RI as the predictor for RAI therapy failure are needed to investigate in both adult and children clinical settings.

Radioiodine therapy of Graves' disease

Graves' disease (GD), the most common cause of hyperthyroidism, is an autoimmune disease directly caused by circulating autoantibodies that bind and activate the TSH receptor, inducing metabolic activation of the thyroid gland; this may be associated with important cardiac (atrial fibrillation) and ocular (ophthalmopathy) complications. Treating GD with real curative intent implies the full elimination of the functioning thyroid parenchyma using surgery or radioactive iodine therapy (RAI). RAI has been used in humans with hyperthyroidism since 1941, thanks to the pioneering work of a physician (Dr. Saul Hertz) and a physicist (Dr. Arthur Roberts). The rationale of RAI is based on the effect of radiation of ¹³¹I on target cells leading to DNA damage, both directly, through breakage of molecular bonds, and indirectly through the formation of free radicals. In particular, irradiation causes a broad spectrum of cellular damage due to the production of reactive oxygen species and lipid peroxidation of the plasma membrane. Thus, RAI-related cellular death takes place through both apoptosis and necrosis. The aim of this review was to summarize indications, efficacy, safety profile, and dosimetric aspects of RAI treatment in patients affected by GD.

Management of Graves Thyroidal and Extrathyroidal Disease: An Update

CONTEXT

Invited update on the management of systemic autoimmune Graves disease (GD) and associated Graves orbitopathy (GO).

EVIDENCE ACQUISITION

Guidelines, pertinent original articles, systemic reviews, and meta-analyses.

EVIDENCE SYNTHESIS

Thyrotropin receptor antibodies (TSH-R-Abs), foremost the stimulatory TSH-R-Abs, are a specific biomarker for GD. Their measurement assists in the differential diagnosis of hyperthyroidism and offers accurate and rapid diagnosis of GD. Thyroid ultrasound is a sensitive imaging tool for GD. Worldwide, thionamides are the favored treatment (12-18 months) of newly diagnosed GD, with methimazole (MMI) as the preferred drug. Patients with persistently high TSH-R-Abs and/or persistent hyperthyroidism at 18 months, or with a relapse after completing a course of MMI, can opt for a definitive therapy with radioactive iodine (RAI) or total thyroidectomy (TX). Continued long-term, low-dose MMI administration is a valuable and safe alternative. Patient choice, both at initial presentation of GD and at recurrence, should be emphasized. Propylthiouracil is preferred to MMI during the first trimester of pregnancy. TX is best performed by a high-volume thyroid surgeon. RAI should be avoided in GD patients with active GO, especially in smokers. Recently, a promising therapy with an anti-insulin-like growth factor-1 monoclonal antibody for patients with active/severe GO was approved by the Food and Drug Administration. COVID-19 infection is a risk factor for poorly controlled hyperthyroidism, which contributes to the infection-related mortality risk. If GO is not severe, systemic steroid treatment should be postponed during COVID-19 while local treatment and preventive measures are offered.

CONCLUSIONS

A clear trend towards serological diagnosis and medical treatment of GD has emerged.

A Clinical Debate: What Is the Therapeutic Choice for Recurrent Graves' Hyperthyroidism?

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Predictive factors for early hypothyroidism following the radioactive iodine therapy in Graves' disease patients

BACKGROUND

Radioactive iodine (RAI) therapy is an important treatment option for Graves' disease (GD), the main side effect of RAI treatment is hypothyroidism, and the factors resulting in hypothyroidism are still controversial. The purpose of this retrospective study was to clarify the possible risk factors of early hypothyroidism after RAI therapy in Graves' disease.

METHODS

We reviewed 312 GD patients treated with RAI between January 2017 to December 2018, collected the potential risk factors, and analyzed the relationship between these variables and early hypothyroidism.

RESULTS

After 6 months' follow-up, 218 (69.87%) patients were evaluated as early hypothyroid. Male gender, shorter duration of disease, smaller thyroid weight, lower 2-h radioactive iodine uptake (RAIU), 6-h RAIU, 24-h RAIU and 6/24-h uptake ratio, lower administered dosages were significantly associated with early hypothyroidism. Logistics regression analysis showed that male gender, smaller thyroid weight and lower 6-h RAIU were associated with early hypothyroidism. Multi-factors combined ROC curve analysis suggested that the predictive power of male gender, smaller thyroid weight and lower 6-h RAIU for early hypothyroidism was 0.711.

CONCLUSIONS

Our results show that RAI is an effective therapy for GD and most of the cured patients became to hypothyroid within 6 months. Male gender, smaller thyroid weight and lower 6-h RAIU are the main risk factors for early hypothyroidism.

Radioactive iodine therapy for pediatric Graves' disease: a single-center experience over a 10-year period

Introduction Only about 30% of pediatric patients with Graves' hyperthyroidism achieve remission with medical therapy, and therefore radioactive iodine (RAI) therapy is often used as a definitive treatment. Although the goal of RAI is permanent hypothyroidism, this is not consistently achieved. We conducted a chart review to determine the factors associated with the success of RAI. We also tried to determine optimal follow-up post RAI and if there was an optimal L-thyroxine dose that would normalize the hypothyroid state quickly. Methods This is a retrospective chart review of Graves' patients who underwent RAI between 2008 and 2017. We included age, sex, time from diagnosis, thyroid gland size, total dose of I-131 and dose in μCi/g of thyroid tissue. Patients were grouped based on outcome and analyzed using univariate and multivariate logistic regression. Follow-up thyroid levels post RAI and after starting l-thyroxine were analyzed. Results There were 78 ablations including six repeat ablations. Seventy-three percent became hypothyroid, 23% remained overtly or subclinically hyperthyroid, and 4% were euthyroid. Smaller thyroid size (36.5 vs. 47.4 g; p = 0.037) and higher dose of I-131 (242 vs. 212 μCi/g thyroid tissue; p = 0.013) were associated with a higher likelihood of hypothyroidism. Most patients remained hyperthyroid at 1 month post RAI, but by 3 months the majority became hypothyroid. There was no clear L-thyroxine dose that normalized hypothyroidism quickly. Conclusions An I-131 dose close to 250 μCi/g of thyroid tissue has a higher likelihood of achieving hypothyroidism. Testing at 2-3 months after RAI is most helpful to confirm response to RAI.

Update on pediatric hyperthyroidism

PURPOSE OF REVIEW

This review is intended to highlight recent studies which provide new data on the epidemiology and management of children with hyperthyroidism, including neonates.

RECENT FINDINGS

A French study demonstrates differences in age-related trends in incidence of hyperthyroidism in males versus females and suggests the overall incidence may be increasing. New studies confirm the effectiveness and safety of long-term medical therapy (up to 10 years), including from the first randomized trial of short-term versus long-term therapy. Radioiodine ablation (RAI) is the main alternative therapy, though surgery may have some advantages if done in a high-volume center; using higher weight-based doses of I-131 (250 μCI/g thyroid tissue) could increase proportion of patients achieving hypothyroidism and decrease repeat ablations. Maternal or neonatal thyroid-stimulating hormone (TSH) receptor antibodies in children of mothers with Graves' disease, and TSH at 3-7 days of age are good predictors of which neonates will have problems.

SUMMARY

More research is needed on the epidemiology of Graves' disease. Long-term medical therapy well past two years should be considered an option in compliant patients to decrease the number who need definitive therapy. For those receiving RAI, a dose of about 250 μCI/g thyroid tissue should result in fewer cases of persistent hyperthyroidism than lower doses.

The success rate of radioactive iodine therapy for Graves' disease in iodine-replete area and affecting factors: a single-center study

OBJECTIVE

Initial treatment options for Graves' disease include antithyroid drugs, radioactive iodine (RAI), and surgery. Because of similar effects of three modalities, initial treatment preferences differ by country to country. In Korea, iodine-replete area, RAI was used as a second-line option. For these reasons, the RAI success rate in Korea might differ from other countries.

METHODS

A total of 247 patients were enrolled. The primary outcome was cumulative success rate in the first year, and the secondary outcome was factors that affected the success. Delayed response, which included patients who attained successful RAI during the follow-up, after the first year without further RAI, and factors that affected the delayed response were reviewed.

RESULTS

The cumulative success rate in the first year was 62.8%. Higher RAI activity [odds ratio (OR) 2.56, P = 0.02], longer disease duration (OR 0.43, P = 0.01), larger goiter (OR 0.31, P = 0.01), and higher post-RAI fT4 (fT4 between upper normal limit (UNL) to 1.5 × UNL; OR 0.24; P < 0.01, 1.5 × UNL<; OR 0.08; P < 0.01) were associated with RAI success. Twenty-seven patients showed delayed response, and goiter size (P < 0.05), pre-RAI TSH receptor Ab (TRAb) level (P < 0.01) and post-RAI fT4 (P < 0.01) were associated.

CONCLUSION

The success rate of the first RAI in Korea was lower than that in other countries. Delayed response was observed in patients with smaller goiter, low pre-RAI TRAb, and low post-RAI fT4. In these patients, clinical follow-up with monitoring could be an option, and decision of optimal timing of first RAI is crucial.

Two-year outcomes of single-session high-intensity focused ultrasound (HIFU) treatment in persistent or relapsed Graves' disease

OBJECTIVE

To evaluate the longer-term disease relapse of ultrasound (US)-guided high-intensity focused ultrasound (HIFU) ablation as a treatment for persistent/relapsed Graves' disease (GD).

METHODS

After ethics approval, consecutive patients with persistent or relapsed GD who underwent bilateral US-guided HIFU ablation from 2016 to 2017 were retrospectively analyzed. Altogether, 75 patients received HIFU ablation of the central portion of the right and left thyroid lobes with areas near the trachea-esophageal groove and common carotid artery un-ablated. They were followed for 24 months or longer. Baseline thyrotropin (TSH), free T4, anti-thyroid autoantibodies, and TSH receptor (TSHR) antibody were checked. Primary outcome was the 24-month relapse rate. Relapse referred to hyperthyroidism (free T4 (FT4) > 23 pmol/L) afterwards. Variables associated with relapse were analyzed by binary logistic regression.

RESULTS

The cohort comprised mostly females (84.0%) with a mean age of 42.05 ± 10.74 years. The 24-month relapse rate was 41.3% with 31 patients suffering a relapse. No patient suffered from hypothyroidism. Three patients (4.0%) suffered from temporary vocal cord palsy but these injuries recovered spontaneously after 2 months. In univariate analysis, higher daily dose of carbimazole (OR = 1.125, 95% CI = 1.023-1.237, p = 0.015) and higher baseline TSHR level (OR = 1.085, 95% CI = 1.022-1.152, p = 0.007) were significant factors for disease relapse. In the multivariate analysis, higher baseline TSHR level was a significant independent factor for disease relapse within 24 months (OR = 1.079, 95% CI = 1.014-1.148, p = 0.016).

CONCLUSIONS

US-guided HIFU of the thyroid gland was a safe and relatively efficacious treatment in the longer term for patients with persistent or relapsed GD.

KEY POINTS

• US-guided HIFU ablation is relatively efficacious in the longer term. • US-guided HIFU ablation of the thyroid is safe. • Higher TSHR level may lead to higher disease relapse after treatment.

Graves' Disease: Can It Be Cured?

Whether or not Graves' hyperthyroidism can be really cured, depends on the definition of "cure." If eradication of thyroid hormone excess suffices for the label "cure," then all patients can be cured because total thyroidectomy or high doses of ¹³¹I will abolish hyperthyroidism albeit at the expense of creating another disease (hypothyroidism) requiring lifelong medication with levothyroxine. I would not call this a "cure," which I would like to define as a state with stable thyroid stimulating hormone (TSH), free thyroxine, and triiodothyronine serum concentrations in the normal range in the absence of any thyroid medication. Surgery and radioiodine are unlikely to result in so-defined cures, as their preferable aim as stated in guidelines is to cause permanent hypothyroidism. Discontinuation of antithyroid drugs is followed by 50% recurrences within 4 years; before starting therapy the risk of recurrences can be estimated with the Graves' Recurrent Events After Therapy (GREAT) score. At 20-year follow-up about 62% had developed recurrent hyperthyroidism, 8% had subclinical hypothyroidism, and 3% overt hypothyroidism related to TSH receptor blocking antibodies and thyroid peroxidase antibodies. Only 27% was in remission, and might be considered cured. If the definition of "cure" would also include the disappearance of thyroid antibodies in serum, the proportion of cured patients would become even lower.