Comparison of long-term antithyroid drugs versus radioactive iodine or surgery for Graves' disease: A review of the literature

Risk of recurrence at the time of withdrawal of short- or long-term methimazole therapy in patients with Graves' hyperthyroidism: a randomized trial and a risk-scoring model

PURPOSE

In Graves' disease, administration of low-dose methimazole for more than 60 months induces higher remission rates compared with the conventional duration of 12-18 months. However, the risk of recurrence and its predictors beyond 48 months of drug withdrawal are not known. The aims of this study were to determine the risk of recurrence during 84 months after withdrawal of short- or long-term methimazole therapy and a risk stratification for recurrence of hyperthyroidism.

METHODS

A total of 258 patients were treated with methimazole for a median of 18 months and randomized to discontinuation of the drug(conventional short-term group; n = 128) or continuation of the treatment up to 60-120 months(long-term group; n = 130). Patients were followed for 84 months after methimazole withdrawal. Cox proportional hazards modeling was performed to identify factors associated with relapse and develop a risk-scoring model at the time of discontinuing the treatment.

RESULTS

Hyperthyroidism recurred in 67 of 120(56%) of conventionally-treated patients versus 20 of 118(17%) of those who received long-term methimazole treatment, p < 0.001. Age, sex, goiter grade, triiodothyronine, thyrotropin, and thyrotropin receptor antibodies were significant predictors of recurrence in both "conventional" and "long-term" groups but free thyroxine just in the "long-term" group. The risk-scoring model had a good discrimination power (optimism corrected c-index = 0.78,95%CI = 0.73-0.82) with a range of 0-14 and sensitivity of 86% and specificity of 62% at the risk-score of eight.

CONCLUSION

A relapse-free state was achieved in 83% of patients with Graves' hyperthyroidism 84 months after cessation of long-term methimazole treatment which could be predicted by some significant predictors in a simple risk-scoring system.

[The features of regulatory T-blood cells subpopulation and the level of CD25 expression in patients with Graves' disease in dynamics after radioactive iodine therapy]

BACKGROUND

The content of regulatory T cells (Treg) at different stages in formation of effector subpopulations and the level of CD25 expression on the membrane of their various fractions in Graves' disease can determine the long-term autoimmune process persistence and be the target of immunotropic therapy of the disease.

AIM

To study the features of regulatory T-blood cells subpopulation and the level of CD25 expression in patients with Graves' disease in dynamics after radioactive iodine therapy (RIT) to identify the specific Treg subpopulations for potential immunotropic therapy targets of the disease.

MATERIALS AND METHODS

A single-center, prospective, cohort, open, controlled study was conducted with the participation of women with laboratory-confirmed Graves' disease. The features of regulatory T-blood cells subpopulation and the level of expression (MFI) CD25 surface receptor were studied by flow cytometry using direct immunofluorescence using monoclonal antibodies.

RESULTS

The study included 36 women with recurrent Graves' disease, middle age 46.34±14.32 years. In patients with Graves' disease before and during the entire period after RIT a low percentage of naive (CD45R0-CD62L+) and terminally differentiated (CD45R0-CD62L-) Treg was established relative to the control, and on 3 and 6 months after RIT a significant decrease of cells with this phenotype was revealed relative to the values detected in patients before and 1 month after RIT (p&lt;0.001). Against the background of compensated hypothyroidism the most significant changes of expression CD25 receptor in patients with Graves' disease were found on 3 and 6 months after RIT: reduced levels of MFI CD25 on surface of naive and terminally differentiated Treg.

CONCLUSION

A decrease in the level of naive Treg was found (apparently due to a violation of differentiation processes in thymus) and terminally differentiated Tregs (due to maturation and survival processes), which are supplemented by a reduced expression of the CD25 receptor on the surface of these cells and do not depend on hyperthyroidism compensation, the titer of TSH receptor antibodies, previous conservative therapy with thiamazole and RIT. The obtained new data reveal the role of naive and terminally differentiated Treg subpopulations in immunopathogenesis and help to outline further ways to develop approaches for immunotropic therapy.

Radioactive Iodine: A Living History

Background: Before the development of antithyroid drugs in the 1940s, treatment of Graves' hyperthyroidism was primarily surgical. Surgical mortality was quite variable, but a significant minority of patients died during or after surgery. Summary: In 1936, Karl Compton, President of the Massachusetts Institute of Technology, in a lecture attended by Massachusetts General Hospital physicians, suggested that artificially radioactive isotopes might be useful for studying metabolism. By 1942, Hertz and Roberts reported on the successful use of radioactive iodine (RAI) to treat Graves' hyperthyroidism. RAI uptake was subsequently demonstrated in well-differentiated thyroid cancer metastases. In 1948, Seidlin demonstrated stimulation of uptake in thyroid cancer metastases by thyrotropin (TSH). By 1990, 69% of endocrinologists in North America recommended RAI for Graves' hyperthyroidism. Currently RAI is less frequently used for Graves' hyperthyroidism, related to concerns about exacerbation of thyroid eye disease, about radiation exposure, and about potential adverse consequences of permanent hypothyroidism. Similarly, RAI was administered to the majority of patients with thyroid cancer for decades, but its use is now more selective. Conclusions: RAI is a remarkable example of interinstitutional cooperation between physicians and scientists to transition from bench to bedside in only three years. It is the model for a theranostic approach to disease (the simultaneous use of a radioactive drug for diagnosis and therapy). The future of RAI is less certain; inhibition of TSH receptor stimulating antibodies in Graves' disease and more precise targeting of genes that drive thyroid oncogenesis may diminish the use of RAI. Alternatively, redifferentiation techniques may improve the efficacy of RAI in RAI-refractory thyroid cancer.

Hyperthyroidism: aetiology, pathogenesis, diagnosis, management, complications, and prognosis

Hyperthyroidism is a common condition with a global prevalence of 0·2-1·3%. When clinical suspicion of hyperthyroidism arises, it should be confirmed by biochemical tests (eg, low TSH, high free thyroxine [FT4], or high free tri-iodothyonine [FT3]). If hyperthyroidism is confirmed by biochemical tests, a nosological diagnosis should be done to find out which disease is causing the hyperthyroidism. Helpful tools are TSH-receptor antibodies, thyroid peroxidase antibodies, thyroid ultrasonography, and scintigraphy. Hyperthyroidism is mostly caused by Graves' hyperthyroidism (70%) or toxic nodular goitre (16%). Hyperthyroidism can also be caused by subacute granulomatous thyroiditis (3%) and drugs (9%) such as amiodarone, tyrosine kinase inhibitors, and immune checkpoint inhibitors. Disease-specific recommendations are given. Currently, Graves' hyperthyroidism is preferably treated with antithyroid drugs. However, recurrence of hyperthyroidism after a 12-18 month course of antithyroid drugs occurs in approximately 50% of patients. Being younger than 40 years, having FT4 concentrations that are 40 pmol/L or higher, having TSH-binding inhibitory immunoglobulins that are higher than 6 U/L, and having a goitre size that is equivalent to or larger than WHO grade 2 before the start of treatment with antithyroid drugs increase risk of recurrence. Long-term treatment with antithyroid drugs (ie, 5-10 years of treatment) is feasible and associated with fewer recurrences (15%) than short-term treatment (ie, 12-18 months of treatment). Toxic nodular goitre is mostly treated with radioiodine (131I) or thyroidectomy and is rarely treated with radiofrequency ablation. Destructive thyrotoxicosis is usually mild and transient, requiring steroids only in severe cases. Specific attention is given to patients with hyperthyroidism who are pregnant, have COVID-19, or have other complications (eg, atrial fibrillation, thyrotoxic periodic paralysis, and thyroid storm). Hyperthyroidism is associated with increased mortality. Prognosis might be improved by rapid and sustained control of hyperthyroidism. Innovative new treatments are expected for Graves' disease, by targeting B cells or TSH receptors.

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.

Long-term follow-up of Graves' orbitopathy after treatment with short-term 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 GO in patients with Graves' disease treated with different therapeutic modalities for hyperthyroidism.

METHODS

A total of 1163 patients with Graves' disease entered this study; 263 patients were treated with radioiodine and 808 patients received MMI therapy for a median of 18 months of whom, 178 patients continued MMI for a total of 96 months (long-term MMI). Thyroid hormonal status and GO were evaluated regularly for a median of 159 months since enrollment.

RESULTS

Rates of relapse, euthyroidism and hypothyroidism at the end of the follow-up were: radioiodine treatment: 16%, 22% and 62%, short-term MMI group: 59%, 36% and 5% and long-term MMI group: 18%, 80% and 2%, respectively. In 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, p<0.004. The overall worsening and de novo development of GO from>18-234 months was 26(9.9%) in radioiodine and 8(4.5%) in LT-MMI groups, p<0.037. No case of worsening or new onset of GO was observed in patients treated with long-term MMI from>60-234 months of follow-up.

CONCLUSION

Progression and development of GO were associated more with radioiodine than MMI treatment; GO may appear de novo or worsen years after radioiodine but not after long-term MMI therapy.

Risk Factors for Granulocytopenia in Patients with Graves' Disease Receiving Antithyroid Drugs

Objective

To study the risk factors for granulocytopenia caused by antithyroid drugs.

Methods

Patients who were diagnosed with Graves' hyperthyroidism and regularly treated with antithyroid drugs (ATDs) from January 2010 to July 2022 at Nanjing Drum Tower Hospital, aged >18 years, were selected for general information and laboratory tests and divided into two groups according to the occurrence of granulocytopenia. Independent risk factors for the development of granulocytopenia in patients treated with ATDs were analyzed using one-way and multiway logistic regression analyses, and the predictive value of each index was evaluated using the receiver operating characteristic (ROC) curve and the area under the curve (AUC).

Results

A total of 818 patients were enrolled, of which 95 developed granulocytopenia. Univariate analysis revealed that sex, white blood cell (WBC) counts, neutrophil-to-lymphocyte ratio (NLR), glutamic-pyruvic transaminase (ALT), aspartate transaminase (AST), free triiodothyronine (FT3), free thyroxine (FT4), and thyroid stimulating hormone (TSH) before medication were risk factors for ATD-induced granulocytopenia (P < 0.05). The abovementioned indicators were taken as independent variables, and multivariate logistic regression analysis showed that female sex, higher ALT levels before medication, and lower NLR and WBC levels were independent risk factors for granulocytopenia using ATDs (P < 0.05). ROC curve analysis showed that sex, NLR, ALT, and WBC count had significant predictive values (P < 0.05), and NLR and WBC count had higher predictive values (AUC = 0.916 and 0.700, respectively).

Conclusion

Sex, NLR, ALT, and WBC were the main risk factors for granulocytopenia in patients with ATD.

Efficacy and Safety of Long-Term Methimazole versus Radioactive Iodine in the Treatment of Toxic Multinodular Goiter

BACKGRUOUND

This study compared the degree of sustained control of hyperthyroidism in patients with toxic multinodular goiter (TMNG) treated with long-term methimazole (LT-MMI) or radioactive iodine (RAI).

METHODS

In this clinical trial, 130 untreated patients with TMNG were randomized to either LT-MMI or RAI treatment. Both groups were followed for 108 to 148 months, with median follow-up durations of 120 and 132 months in the LT-MMI and RAI groups, respectively. Both groups of patients were followed every 1 to 3 months in the first year and every 6 months thereafter.

RESULTS

After excluding patients in whom the treatment modality was changed and those who were lost to follow-up, 53 patients in the LT-MMI group and 54 in the RAI group completed the study. At the end of the study period, 50 (96%) and 25 (46%) patients were euthyroid, and two (4%) and 25 (46%) were hypothyroid in LT-MMI and RAI groups, respectively. In the RAI group, four (8%) patients had subclinical hyperthyroidism. The mean time to euthyroidism was 4.3±1.3 months in LT-MMI patients and 16.3± 15.0 months in RAI recipients (P<0.001). Patients treated with LT-MMI spent 95.8%±5.9% of the 12-year study period in a euthyroid state, whereas this proportion was 72.4%±14.8% in the RAI-treated patients (P<0.001). No major treatment-related adverse events were observed in either group.

CONCLUSION

In patients with TMNG, LT-MMI therapy is superior to RAI treatment, as shown by the earlier achievement of euthyroidism and the longer duration of sustained normal serum thyrotropin.

Long-term management of Graves disease: a narrative review

Graves disease (GD) is the most common cause of hyperthyroidism, accounting for more than 90% of cases in Korea. Patients with GD are treated with any of the following: antithyroid drugs (ATDs), radioactive iodine (RAI) therapy, or thyroidectomy. Most patients begin treatment with ATDs, and clinical guidelines suggest that the appropriate treatment period is 12 to 18 months. While RAI treatment and surgery manage thyrotoxicosis by destroying or removing thyroid tissue, ATDs control thyrotoxicosis by inhibiting thyroid hormone synthesis and preserving the thyroid gland. Although ATDs efficiently control thyrotoxicosis symptoms, they do not correct the main etiology of GD; therefore, frequent relapses can follow. Recently, a large amount of data has been collected on long-term ATDs for GD, and low-dose methimazole (MMZ) is expected to be a good option for remission. For the long-term management of recurrent GD, it is important to induce remission by evaluating the patient's drug response, stopping ATDs at an appropriate time, and actively switching to surgery or RAI therapy, if indicated. Continuing drug treatment for an extended time is now encouraged in patients with a high possibility of remission with low-dose MMZ. It is also important to pay attention to the quality of life of the patients. This review aimed to summarize the appropriate treatment methods and timing of treatment transition in patients who relapsed several times while receiving treatment for GD.

Treatment of post-radioactive iodine relapse of hyperthyroidism: comparison of long-term methimazole and radioactive iodine treatment

BACKGROUND

This study aimed to compare the time to achieve euthyroidism and sustained control of hyperthyroidism after treatment with radioactive iodine (RAI) or long-term methimazole (LT-MMI) in patients with post-RAI relapsed hyperthyroidism.

METHODS

Sixty four patients with recurrence of hyperthyroidism after RAI treatment were randomly assigned to either RAI or LT-MMI treatment. Both groups were followed every 1-3 months in the first year and then every 6 months for a total of 60 months.

RESULTS

In RAI and LT-MMI groups, mean age was 49.0 ± 12.1 and 50.1 ± 14.6 years and time of relapse of hyperthyroidism after previous RAI treatment was 23.2 ± 18.8 and 20.8 ± 17.1 months, respectively. At the end of study, in the LT-MMI group, 31 (97%) and 1 (3%) were euthyroid and hypothyroid, respectively; in the RAI group, 8 (25%) patients were euthyroid, whereas 18 (56%), 3 (9.5%) and 3 (9.5%) had overt hypothyroidism, subclinical hypothyroidism and hyperthyroidism, respectively. Mean time to euthyroidism was 9.4 ± 5.0 months in the RAI group and 3.5 ± 2.8 months in the LT-MMI group (p < 0.001). Patients in the RAI group spent 77.7 ± 14.0 percent and those in the LT-MMI group spent 95.2 ± 5.9 percent of 60 months in the euthyroid state (p < 0.001).

CONCLUSION

In patients with post-RAI relapse of hyperthyroidism, LT-MMI treatment was superior to radioiodine because of faster achievement of euthyroidism and more sustained control of hyperthyroidism during 60 months of follow-up.

Revisiting the role of surgery in the treatment of Graves' disease

Graves' disease (GD) can be managed by antithyroid drugs (ATD), radioactive iodine (RAI) and surgery. Thyroidectomy offers the highest success rates for both primary and persistent disease, yet it is the least recommended or utilized option reaching <1% for primary disease and <25% for persistent disease. Several surveys have found surgery to be the least recommended by endocrinologists worldwide. With the development of remote access thyroidectomies and intraoperative nerve monitoring of the recurrent laryngeal nerve, combined with current knowledge of possible risks associated with RAI or failure of ATDs, revaluation of the benefit to harm ratio of surgery in the treatment of GD is warranted. The aim of this review is to discuss possible reasons for the low proportion of surgery in the treatment of GD, emphasizing an evidence-based approach to the clinicians' preferences for surgical referrals, surgical indications and confronting traditional reasons and concerns relating to the low referral rate with up-to-date data.

Appropriate duration of antithyroid drug treatment as a predictor for relapse of Graves' disease: a systematic scoping review

BACKGROUND

Following the conventional 12-18 month antithyroid drug (ATD) treatment in Graves' disease (GD), 50% of patients experience relapse of hyperthyroidism.

OBJECTIVE

The aim of this systematic scoping review was critical appraisal of duration of ATD therapy in the last 80 years.

METHODS

Articles were identified through the search of PubMed from January 1, 1941 to April 30, 2021. All study types were included. Articles were eligible if they reported data on the length of ATD treatment, particularly thyroid hormones and TSH receptor antibodies (TRAb) concentrations and specifically those with data on the remission and/or relapse rates.

RESULTS

We described major progress regarding the duration of ATD therapy and related outcomes at every 20 years. Articles of 1941-1960 were mainly concerned with determination of favorable treatment, minimal effective dose, side effects and rate of remission after < 12-month ATD therapy. Studies with larger number of patients and longer follow-ups appeared in 1961-1980; higher remission rate after 18-24 months versus 6 months of ATD therapy was reported. Articles of 1981-2000 focused on identification of factors associated with high relapse rates after discontinuation of ATD. In 2001-2021, ATD became the first choice of treatment in many countries. However, 12-18 months of ATD therapy was arbitrarily chosen as the appropriate option. According to recent studies, persistent normalization of TRAb occurs after 5 years of methimazole therapy and ATD treatment of > 60 months could offer a 4-year remission rate of 85%.

CONCLUSION

Long-term ATD treatment for more than 60 months is safe and effective, has the highest remission rate and cures most patients with GD; hence, it should be considered as the most appropriate duration for ATD therapy in these patients.

The Study of Biological Activity of a New Thieno[2,3-D]-Pyrimidine-Based Neutral Antagonist of Thyrotropin Receptor

The development of low-molecular-weight antagonists of thyroid-stimulating hormone (TSH) receptor is a promising trend in the treatment of autoimmune hyperthyroidism. We studied the effect of thieno[2,3-d]-pyrimidine derivative TPY1 on TSH-stimulated synthesis of thyroid hormones in the culture of FRTL-5 thyrocytes and on thyroliberin-stimulated production of thyroid hormones in rat blood. Preincubation of FRTL-5 cells with TPY1 suppressed the stimulatory effect of TSH on the synthesis of thyroxine and triiodothyronine. Intraperitoneal injection of TPY1 in a dose of 25 mg/kg reduced thyroliberin-stimulated levels of thyroid hormones in the blood and inhibited the expression of genes encoding thyroid peroxidase, thyroglobulin, and Na⁺/I- cotransporter responsible for thyroxine synthesis. In the absence of thyroliberin stimulation, TPY1 did not affect the levels of thyroid hormones and expression of thyroidogenesis genes. Thus, a new TPY1 antagonist of TSH receptor can be a prototype of a drug for the treatment of autoimmune hyperthyroidism.

New Therapeutic Horizon of Graves' Hyperthyroidism: Treatment Regimens Based on Immunology and Ingredients From Traditional Chinese Medicine

Graves’ disease is an autoimmune disease characterized by goiter and hyperthyroidism, and 25% patients develop GO. Traditional treatment options, such as antithyroid drugs, radioiodine or thyroidectomy, have remained largely unchanged over the past 70 years. For many patients, there is a high rate of recurrence after antithyroid drugs and lifelong hypothyroidism after ablation and thyroidectomy. The symptoms and quality of life of some patients have not been effectively improved. The clinical demand for new therapeutic regimens, coupled with a deeper understanding of the pathophysiology and immunobiology of Graves’ disease, has led to the emergence of several new therapeutic ideas, including biologics, small molecule peptides, immunomodulators and teprotumumab, a specific antibody targeting IGF-1R. Besides, the elements of TCM have attracted more and more interests in modern medicine, because some effective components have been successfully used in the treatment of autoimmune diseases. Based on the pathophysiology and efficacy of clinical management and treatment in Graves’ hyperthyroidism, here we review the new strategies under investigation and summarize the effective components of traditional Chinese medicine used for Graves’ hyperthyroidism, and explore their mechanisms. These therapies have opened a new window for the treatment of Graves’ disease, but the exact mechanism and the research direction still need to be further explored.

Comprehensive Analysis of lncRNA Expression Profile and the Potential Role of ENST00000604491 in Graves’ Disease

Background. Graves’ disease (GD) is one of the most common autoimmune diseases worldwide and develops in 20 to 50 cases per 100,000 persons annually. Long noncoding RNAs (lncRNAs) are widely expressed in multiple human diseases and have pivotal functions in gene regulation. This study is aimed at determining the lncRNA profile in peripheral blood mononuclear cells (PBMCs) from GD patients and investigating the role of ENST00000604491 in GD. Methods. A total of 31 GD patients and 32 normal controls were enrolled in the study. Next-generation sequencing was performed to identify the dysregulated lncRNAs in the PBMCs from the 5 GD patients and 5 normal controls, and 26 GD patients and 27 controls were used to verify the selected lncRNAs. The relative expression of verified lncRNAs, forkhead box P1 (FOXP1), and IKAROS family zinc finger 3 (IKZF3) from these samples was detected by quantitative real-time PCR. The potential biomarker value was assessed by using receiver operating characteristic (ROC) curve analysis. Results. A total of 37,683 dysregulated expressed lncRNAs were indicated, of which 5 lncRNAs were significantly upregulated and 83 lncRNAs were remarkably downregulated in the GD patients compared with healthy subjects. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analyses showed that abnormally expressed lncRNAs were mainly enriched in immune system-related signalling pathways. Among the selected lncRNAs, the relative expression of ENST00000604491 was significantly downregulated and negatively correlated with the serum levels of thyroid-stimulating hormone receptor antibodies (TRAb) in GD patients. Further studies confirmed that decreased FOXP1 expression was inversely correlated with serum TRAb levels in GD patients. Moreover, there was a notably positive correlation between ENST00000604491 expression and FOXP1 transcript levels in GD. The area under the ROC curve of ENST00000604491 was up to 0.74 (95% confidence interval: 0.60-0.87, $p<0.01$ ), and the sensitivity and specificity were 53.85% and 88.89%, respectively. Conclusion. The present study identifies ENST00000604491 as a significantly attenuated lncRNA in GD patients, which may contribute to the pathogenesis of GD by regulating FOXP1 and represent a potential biomarker for GD.

Long-term antithyroid drug therapy

PURPOSE OF REVIEW

Over the last 1-2 decades, patients and physicians have preferred antithyroid drug therapy as the initial treatment of Graves' disease, rather than radioactive iodine or surgery. More recently, the concept of long-term antithyroid drug therapy (LTADT; >24 months of treatment) has also become increasingly popular.

RECENT FINDINGS

Data from cohort studies and a prospective randomized trial suggest that LTATD therapy is safe and is associated with a higher chance of remission from Graves' disease than is shorter-term therapy. Also, LTADT may be associated with better quality of life and other clinical outcomes compared to radioiodine and surgery.

SUMMARY

Long-term antithyroid drug therapy is appropriate for children and young adults. This approach is a reasonable option in those who are doing well on a stable low dose of antithyroid drug therapy, and especially those who wish to avoid definitive treatment with radioactive iodine or surgery, given their inherent risks and need for lifelong hormonal replacement therapy.