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

Does Graves' Disease Truly Increase the Risk of Complications After Total Thyroidectomy?

INTRODUCTION

Total thyroidectomy (TTx) has been reported to be more challenging in patients with Graves' disease, especially in those who are hyperthyroid at the time of surgery. Our aim was to compare outcomes in patients undergoing TTx for Graves' disease compared to other thyroid diseases at a large academic institution with high-volume fellowship-trained endocrine surgeons.

METHODS

In our retrospective analysis from December 2015 to May 2023, patients undergoing TTx for Graves' disease were compared to those undergoing TTx for all other indications excluding advanced malignancy (poorly differentiated thyroid cancer and concomitant neck dissections). Patient demographics, biochemical values, and postoperative outcomes were compared. A subgroup analysis was performed comparing hyperthyroid to euthyroid patients at the time of surgery.

RESULTS

There were 589 patients who underwent TTx, of which 227 (38.5%) had Graves' disease compared to 362 (61.5%) without. Intraoperatively in Graves' patients, nerve monitoring was used more frequently (65.6% versus 57.1%; P = 0.04) and there was a higher rate of parathyroid autotransplantation (32.0% versus 14.4%; P < 0.01). Postoperatively, transient voice hoarseness occurred less frequently (4.8% versus 13.6%; P < 0.01) and there was no difference in temporary hypocalcemia rates or hematoma rates. In our subgroup analysis, 83 (36%) of Graves' patients were hyperthyroid (thyroid-stimulating hormone < 0.45 and free T4 > 1.64) at the time of surgery and there were no differences in postoperative complications compared to those who were euthyroid.

CONCLUSIONS

At a high-volume endocrine surgery center, TTx for Graves' disease can be performed safely without significant differences in postoperative outcomes. Hyperthyroid patients demonstrated no differences in postoperative outcomes.

Clinical factors influencing the success rate of radioiodine treatment for Graves' disease

AIMS

To investigate the impact of various clinical factors associated with Graves' disease on the success rate of radioiodine (RAI) therapy for Graves' disease within 3 years, and to determine the optimal range of iodine dosage per unit volume that yields the highest cure rate for Graves' disease within 1 year.

MATERIALS AND METHODS

This retrospective study included patients diagnosed with Graves' disease who underwent RAI therapy at the Second Affiliated Hospital of Anhui Medical University between October 2012 and October 2022. The cumulative success rate was analysed using the Kaplan-Meier method. Univariate and multivariate Cox proportional hazards regression models were employed to evaluate factors associated with successful treatment of Graves' disease. Outcomes were categorized as either success or failure for all patients.

RESULTS

Overall, 1994 patients were enrolled in this study, including 594 (29.8%) male and 1399 (70.2%) female patients. The success and failure groups comprised 1645 (82.4%) and 349 patients (17.6%), respectively, after a 3-year follow-up period. Multivariate regression analysis demonstrated that sex, antithyroid drug (ATD) use before RAI therapy, age, thyroid receptor antibody (TRAb) levels, iodine dose, thyroid mass, and early ATD use before RAI therapy were independent influencing factors for Graves' disease cure.

CONCLUSIONS

We found that female patients and those with TRAbs ≥31.83 IU/L and thyroid mass ≥ 73.42 g had a lower cure rate. Therefore, thyroid size, disease severity, and duration of disease should be comprehensively considered when making treatment decisions and iodine dose selection in clinical practice.

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.

Incidental but Not Insignificant: Thyroid Cancer in Patients with Graves Disease

BACKGROUND

Graves disease is the most common cause of hyperthyroidism in the US. Treatment with antithyroid drugs and radioactive iodine is more commonly used than surgical management with total thyroidectomy (TTx). However, incidentally discovered thyroid cancer (TC) has been described on surgical pathology from patients who underwent surgical treatment of Graves disease, which would be missed with these other treatment strategies. We sought to determine the incidence rate of TC among patients with surgically treated Graves disease.

STUDY DESIGN

We retrospectively reviewed patients with Graves disease who underwent TTx at a single institution from 2011 to 2023. Pathology reports were reviewed for TC. Patient demographics, preoperative laboratory and radiological evaluations, preoperative medical management, and surgical outcomes were compared between patients with and without incidental TC.

RESULTS

There were 934 patients, of whom 60 (6.4%) patients had incidentally discovered TC on pathology. The majority (58.3%) of patients had papillary thyroid carcinoma, followed by 33.3% with papillary microcarcinoma. Preoperative ultrasound (US) was obtained in 564 (60.4%) of patients, with 44.3% with nodules, but only 34 (13.7%) of those with nodules had TC on final pathology. Preoperative fine needle aspiration was obtained in 15 patients with TC, and 8 patients (53.3%) were reported as benign lesions, which ultimately had TC on final pathology. There was no difference in sex, race or ethnicity, preoperative medical management, and postoperative outcomes between the 2 groups.

CONCLUSIONS

Incidental TC was found on surgical pathology in 6.4% of patients undergoing TTx for Graves disease. Preoperative imaging with US and fine needle aspiration were often unreliable at predicting TC. The incidence of TC should not be underestimated when counseling patients on definitive management for Graves disease.

Hyperthyroidism: A Review

Importance

Overt hyperthyroidism, defined as suppressed thyrotropin (previously thyroid-stimulating hormone) and high concentration of triiodothyronine (T3) and/or free thyroxine (FT4), affects approximately 0.2% to 1.4% of people worldwide. Subclinical hyperthyroidism, defined as low concentrations of thyrotropin and normal concentrations of T3 and FT4, affects approximately 0.7% to 1.4% of people worldwide. Untreated hyperthyroidism can cause cardiac arrhythmias, heart failure, osteoporosis, and adverse pregnancy outcomes. It may lead to unintentional weight loss and is associated with increased mortality.

Observations

The most common cause of hyperthyroidism is Graves disease, with a global prevalence of 2% in women and 0.5% in men. Other causes of hyperthyroidism and thyrotoxicosis include toxic nodules and the thyrotoxic phase of thyroiditis. Common symptoms of thyrotoxicosis include anxiety, insomnia, palpitations, unintentional weight loss, diarrhea, and heat intolerance. Patients with Graves disease may have a diffusely enlarged thyroid gland, stare, or exophthalmos on examination. Patients with toxic nodules (ie, in which thyroid nodules develop autonomous function) may have symptoms from local compression of structures in the neck by the thyroid gland, such as dysphagia, orthopnea, or voice changes. Etiology can typically be established based on clinical presentation, thyroid function tests, and thyrotropin-receptor antibody status. Thyroid scintigraphy is recommended if thyroid nodules are present or the etiology is unclear. Thyrotoxicosis from thyroiditis may be observed if symptomatic or treated with supportive care. Treatment options for overt hyperthyroidism from autonomous thyroid nodules or Graves disease include antithyroid drugs, radioactive iodine ablation, and surgery. Treatment for subclinical hyperthyroidism is recommended for patients at highest risk of osteoporosis and cardiovascular disease, such as those older than 65 years or with persistent serum thyrotropin level less than 0.1 mIU/L.

Conclusions and Relevance

Hyperthyroidism affects 2.5% of adults worldwide and is associated with osteoporosis, heart disease, and increased mortality. First-line treatments are antithyroid drugs, thyroid surgery, and radioactive iodine treatment. Treatment choices should be individualized and patient centered.

Effect of liver dysfunction on outcome of radioactive iodine therapy for Graves' disease

Liver dysfunction is a common complication of Graves' disease (GD) that may be caused by excessive thyroid hormone (TH) or anti-thyroid drugs (ATDs). Radioactive iodine (RAI) therapy is one of the first-line treatments for GD, but it is unclear whether it is safe and effective in patients with liver dysfunction. 510 consecutive patients with GD receiving first RAI were enrolled in the study, and followed up at 3-, 6- and 12-month. Liver dysfunction was recorded in 222 (43.5%) patients. GD patients with liver dysfunction had higher serum levels of free triiodothyronine (FT3) (median 27.6 vs. 20.6 pmol/L, p < 0.001) and free thyroxine (FT4) (median 65.4 vs. 53.5 pmol/L, p < 0.001) levels than those with normal liver function. Binary logistic regression analysis showed that duration of disease (OR = 0.951, 95% CI: 0.992-0.980, p = 0.001) and male gender (OR = 1.106, 95% CI: 1.116-2.384; p = 0.011) were significant differential factors for liver dysfunction. Serum TSH levels were higher in patients with liver dysfunction at all 3 follow-up time points (p = 0.014, 0.008, and 0.025 respectively). FT3 level was lower in patients with liver dysfunction at 3-month follow-up (p = 0.047), but the difference disappeared at 6 and 12 months (p = 0.351 and 0.264 respectively). The rate of euthyroidism or hypothyroidism was higher in patients with liver dysfunction than in those with normal liver function at 3 months (74.5% vs 62.5%; p = 0.005) and 6 months (82.1% vs 69.1%; p = 0.002) after RAI treatment, but the difference did not persist at 12-month follow-up (89.6% vs 83.2%, p = 0.081).There were no statistically significant differences in treatment efficacy (94.48% vs 90.31%, p = 0.142), incidence of early-onset hypothyroidism (87.73% vs 83.67%, p = 0.277), and recurrence rate (4.91% vs 7.14%, p = 0.379) between the 2 groups at 12-month follow-up. In conclusion, the efficacy of RAI was comparable in GD patients with liver dysfunction and those with normal liver function.

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.