A Clinical Guide to the Management of Graves’ Disease with Radioactive Iodine

The Role of Surgery in Autoimmune Conditions of the Thyroid

The two most common autoimmune conditions of the thyroid include chronic lymphocytic (Hashimoto's) thyroiditis and Graves' disease. Both conditions can be treated medically, but surgery plays an important role. Hashimoto's thyroiditis and Graves' disease are mediated by autoantibodies that interact directly with the thyroid, creating inflammation and impacting thyroid function. Patients may develop large goiters with compressive symptoms or malignancy requiring surgical intervention. In addition, there are several surgical indications specific to Hashimoto's and Graves' Disease.

The cost effectiveness of treatment modalities for thyrotoxicosis in a U.K. center

OBJECTIVE

This study determined the cost effectiveness of treating thyrotoxicosis using thionamide therapy, radioiodine or surgery in the United Kingdom.

DESIGN

One hundred thirty-five patients diagnosed with thyrotoxicosis (62% Graves' disease, 7% nodular disease, 5% thyroiditis, and 27% unknown aetiology) referred in 12 months were offered a fully informed choice of treatment modality. Thirteen patients with transient thyrotoxicosis were subsequently excluded from the analysis. Seventy-four patients (61%) received an 18-month course of thionamide therapy, 43 received radioiodine therapy (35%), and 5 had a thyroidectomy (4%) within the first year of diagnosis as their primary treatment. A successful outcome ("cure") was defined as euthyroidism 12 months after thionamide therapy or euthyroidism or hypothyroidism on thyroxine replacement at 24 months following radioiodine or thyroidectomy. Costs were calculated for outpatient attendances, laboratory tests, and initial and subsequent treatments.

MAIN OUTCOME

In the thionamide group 73% were "cured" at 30 months after initiating treatment compared to 95% in the radioiodine group and 100% treated by thyroidectomy at 24 months. Cost per "cure" was calculated to be 3,763 pounds (5,644 dollars) per patient who received thionamides, 1,375 pounds (2,063 dollars) per patient given radioiodine and 6,551 pounds (9,826 dollars) per patient who underwent thyroidectomy.

CONCLUSION

The most cost-effective primary treatment modality for thyrotoxicosis is radioiodine.

The surgical management of Graves' disease

BACKGROUND

The historical aspects of the pathophysiology and treatment of Graves' disease are briefly discussed in this paper.

MATERIALS AND METHODS

The three treatment modalities of Graves' disease are anti-thyroid drug therapy, radioactive iodine therapy, and surgery. Although the majority of patients with Graves' disease in the U.S. are treated with radioactive iodine, surgery still plays an important role when patients cannot tolerate anti-thyroid drug therapy, when medical treatment is rejected by patients, or when surgery is deemed the fastest and safest route in managing the patient.

CONCLUSIONS

The indications for surgical management of Graves' disease are discussed with emphasis on available data supporting the extent of thyroid resection based on the incidences of hypothyroidism, recurrence of hyperthyroidism, recurrent laryngeal nerve injury and hypoparathyroidism.

Use of thyroid ultrasound volume in calculating radioactive iodine dose in hyperthyroidism

One hundred twenty-one patients treated with 131I had a thyroid ultrasound to measure thyroid volume precisely. This volume measurement was used to determine the radioactive iodine dose. The average size (+/-SEM) of the thyroid glands measured in this manner was 39.7 cm3 +/- 1.9 cc. A significant correlation was found in the estimated size of the gland by the endocrinologists and the ultrasound volume. Of the 121 patients, 89 patients had the same 131I microcurie per gram of tissue factor to determine the radioactive iodine dose. This group of patients was further evaluated in this study. The average 131I dose (+/-SEM) given was 13.2 mCi +/- 0.5 mCi. The average time until hypothyroidism was achieved 2.85 +/- 0.14 months. Ultrasound provides a safe and precise way to determine actual thyroid size when calculating 131I doses.

Antithyroid drugs for the treatment of hyperthyroidism caused by Graves' disease

Therapy for Graves' disease is not straightforward and often involves complex decision making. Long-term antithyroid drug therapy is appealing because it is nonablative, but it is not for everyone. The physician must weigh the advantages and disadvantages of antithyroid drug treatment and help the patient arrive at an individualized therapeutic strategy that is appropriate and cost-effective.

Treatment of Graves' disease: the American way

The treatment of patients with Graves' disease involves a physician making a clinical decision between one of the three modalities available for treatment, administering the treatment and following the patients. There appears to be a difference in treatment bias for treating the 'average' patient with Graves' disease, with American physicians preferring radioactive iodine while their European and Japanese cohorts prefer long-term anti-thyroid drugs. There are no facts to support this bias. The treating physician usually makes the decision based on his or her preference. In addition, American physicians are under pressure to prescribe the most cost-effective therapy, leading to an even stronger bias towards radioactive iodine.

Radioiodine therapy for Graves' disease: case selection and restrictions recommended to patients in North America

Each of the three major therapies for Graves' disease has its own advantages, disadvantages, indications, and contraindications. Today, radioactive iodine (RAI) therapy is the most commonly employed means of therapy for Graves' disease in the United States, with approximately 70% of patients so treated after initial presentation and an additional fraction of arguably 10-15% treated with RAI after failure of antithyroid drugs or surgery. RAI therapy is acknowledged to have the clear-cut advantage of being safe, with low morbidity and cost. The indications for RAI therapy are clear and noncontroversial for most patients with Graves' disease. Moreover, RAI treatment is employed by some thyroidologists for subclinical thyrotoxicosis (normal T4 or T3 but immeasurable TSH), particularly in patients > age 45 due to risks of atrial fibrillation. RAI therapy is not considered indicated or is contraindicated during breast feeding and in pregnancy, subacute thyroiditis, postpartum thyroiditis, struma ovarii, pituitary (TSH-driven) hyperthyroidism, euthyroid, hyperthyroxinemia, and thyroid hormone resistance. Opinions vary on the use of RAI therapy in children with Graves' disease; generally, a lower age cutoff of 17 years is acceptable in most clinics. Even more controversial is whether RAI therapy in the presence of Graves' ophthalmology constitutes a risk for worsening ophthalmopathy. Resolution of this latter issue awaits more definitive studies, but RAI therapy is likely to remain the first choice for most patients with Graves' disease.

Treatment options for hyperthyroidism

Antithyroid drugs induce sustained remission in only 55% of cases. Radioiodine, the overwhelming choice of specialists, may pose risks, including aggravation of ophthalmopathy. Surgical ablation should be considered only if a highly skilled surgeon is available. Thyroid storm requires aggressive management, and definitive treatment is needed for toxic adenoma or toxic multinodular goiter.