Dose Of Radioactive Iodine Therapy Research Articles

Successful Treatment with Radioiodine for Antithyroid Drug-Induced Agranulocytosis in Graves' Disease

Background: Graves’ disease (GD) is an autoimmune disorder and the leading cause of hyperthyroidism. Antithyroid drugs (ATDs) are available treatment option. Agranulocytosis is a rare but potentially fatal complication of ATD in hyperthyroidism management. The study's objectives include clinical symptoms of ATD-induced agranulocytosis in Graves' illness and the difficulties in clinical care in addition to radioactive iodine therapy (RAIT). Methods: Twelve patients with ATD induced agranulocytosis referred to NINMAS between 2021to 2022 for RAIT therapy were included in this study. All the patients with hyperthyroidism and agranulocytosis or leukopenia were taken in this study. Results: The age of the 12 patients (female: male = 10:3) was 26 to 56 years (mean SD: 38.41±13.9 years). Among the twelve patients 10 were treated with carbimazole and two with PTU for Graves’ disease. Initial dose of ATD was 15-30 mg daily. The most common clinical manifestations were fever (100%), sore throat (41.6%), oral ulcer (16%), rash (41.66%), loose motion (16.66%) and atrial fibrillation (8.33%) with deep vein thrombosis (DVT). Agranulocytosis developed between 7th and 547th days after initiation of ATD; all of them developed early onset except one who developed agranulocytosis after 1.5 years of initiation of ATD. All 12 patients were treated immediately after diagnosis of agranulocytosis following prompt discontinuation of ATD, they were treated with antibiotic with 12 cases, G CSF in one case, KI in one case, glucocorticoid in two cases, and beta blocker in all cases. After intensive and supportive treatment in hospital, all the patients recovered with absolute neutrophil counts of more than 500/mm3 in 5 to 15 days (mean SD: 7.6 3.4 days). Nine patients were treated with lithium carbonate supplement to reduce FT3 level. Average dose of lithium carbonate was 600 mg. After that patients were referred for RAIT. TRAb were positive in seven patients and average were 4.2 U/L. Plasmapheresis was done in three patients and one patient in two times due to high FT4 level before RAIT. Lithium carbonate supplementation reduce thyroid hormone level but not to the optimum level. All the 12 patients were treated with RAIT. Average dose RAI 10.9 mCi, average follow up period 2.3 years. Two patients required second dose of RAIT due to persistent hyperthyroidism. Six patients became hypothyroid, two were in hyperthyroid state (on plan for second therapy), four patients are euthyroid at present and they are on follow up. No fatal condition was found in this study. Conclusion: The most cost-effective method of managing agranulocytosis induced by thionamide-derived ATD is that all patients with thyrotoxicosis must be informed that their white blood cells and differential counts should be checked immediately whenever the “common cold” symptoms occur during treatment, especially within the first three months of medication. Contraindication to ATDs; RAI is a safe and effective alternative. Bangladesh J. Nuclear Med. 26(1): 39-43, 2023

Effect of Single Dose of Radioiodine Therapy on Volume Reduction of Thyroid Gland in Hyperthyroidism

Introduction: Radioactive iodine therapy (RAIT) in patients with hyperthyroidism (HT) causes apoptosis of thyrocytes to bring about restoration of thyroid function. The aim of the study was to find the short term extent of reduction of thyroid gland volume (TGV) by non-invasive quantitative assessment using ultrasound imaging (USG).
 Patients and Methods: This prospective study was conducted on a group of patients who had received RAIT due to primary hyperthyroidism at National Institute of Nuclear Medicine & Allied Sciences (NINMAS). Pre-therapy work up included hormone assay and baseline measurement of TGV by US before administration of appropriate fixed dose RAIT. Short term follow-up with hormone assay and serial measurements of TGV on two occasions were done at three and six months following the RAIT. Observed temporal changes of parameters were analyzed using appropriate statistics.
 Results: Total 117 patients with primary hyperthyroidism had received RAIT with diagnosis of diffuse toxic goiter in 86 patients, toxic multinodular goiter in 21 cases and single toxic nodular goiter in 10 cases. There was a decline of mean TGV from the baseline level of 24 ml to 14 ml at three months followed by a further decline to 9.1 ml at six months. Thus the volume reduction of thyroid gland was calculated to be 42% at three months and 62% at six months. The volume reduction was observed to be in a correlative trend with the normalization of hormone levels. The proportion of patients who showed persistent hyperthyroidism till the study end point was 23%.
 Conclusion: Single dose of radioactive iodine therapy resulted in reduction of TGV up to 62% till six months after RAIT while 23% patients showed persistent hyperthyroidism. The correlative trend of volume reduction with normalization of hormone levels indicates potentiality of TGV to emerge as an adjunct to conventional assessment of treatment efficacy following RAIT. 
 Bangladesh J. Nuclear Med. 21(2): 87-91, July 2018

Association of the Cumulative Dose of Radioactive Iodine Therapy With Overall Survival in Patients With Differentiated Thyroid Cancer and Pulmonary Metastases.

Purpose: The optimal cumulative dose of radioactive iodine therapy (RAIT) for patients with differentiated thyroid cancer (DTC) and pulmonary metastases (PM) is not known, therefore we evaluated the association between the cumulative dose of RAIT and overall survival (OS).Methods: A total of 202 patients with DTC and PM who underwent thyroidectomy and RAIT were analyzed in this study. The median cumulative dose of RAIT was 530 mCi. OS was compared with an age- and sex-matched general population from China to assess relative survival. Multivariable proportional hazards model smoothing by penalized spline was applied to identify independent predictors and examine the adjusted non-linear association of cumulative dose of RAIT and patient age with mortality.Results: The observed survival and relative survival at 10 years was 54.96 and 60.81%, respectively, with the standardized mortality ratio being 5.34. The cumulative dose of RAIT was associated with mortality in a dose-dependent fashion without an apparent cutoff point after adjustment of other variables. A linear but moderate association was found in the dose of 300 to 1,000 mCi. Cumulative dose of RAIT, patient age, diameter of pulmonary metastases, and extrapulmonary metastases were identified as independent predictors for OS. The increasing patient age was associated with mortality in a non-linear pattern, with the optimal threshold being 40 years. With advancing age, the risk of death increases rapidly in patients aged 40 years and younger, but slowly in patients over 40 years.Conclusions: RAIT should be assigned to RAI-avid patients until disease has been controlled or RAIT becomes refractory after consideration of the potential long-term side-effects. Patient age was associated with OS in a non-linear pattern, with a threshold at 40 years. Consideration of age as a binary variable could elucidate a more accurate prognosis in such patients.

Clinical Efficacy of A Single Dose Radioiodine Therapy for Hyperthyroidism

<p><strong>Objective</strong>: Radioiodine is a safe, cheap, and recognized permanent treatment option for patients with hyperthyroidism. Despite, the extensive use of radioiodine therapy in hyperthyroidism there is no consensus regarding the optimal dose of radioiodine. To evaluate the clinical efficacy and our clinical experience with the use of a single dose radioiodine therapy for hyperthyroidism in our institution.</p><p><strong>Methods:</strong> A total of 274 patients who received a single dose of radioactive iodine therapy for hyperthyroidism at our institution between 2007-2015 were retrospectively reviewed. Of these, 186 patients had Graves’ disease (GD), 73 patients had Plummer’s disease (PD), and 15 patients had a single toxic adenoma (STA). All patients received between 10-30mCi of oral radioiodine capsule. The efficacy of therapy was determined 3 months post-therapy using serum thyroid function test, weight and heart rate measurements. Therapy success refers to patients whose outcome was euthyroidism and hypothyroidism post-therapy and treatment failure where patients still manifested with persistent hyperthyroidism.</p><p><strong>Results:</strong> The efficacy of a single dose of radioiodine 3months post-therapy varies with the type of hyperthyroidism, 96% for Graves’s disease, 92% for Plummer’s disease and 100% in single toxic adenoma.</p><p><strong>Conclusion:</strong> Our study showed that a single dose of radioactive iodine therapy 3 months post-therapy is 96% efficient in all types of hyperthyroidism. However, we observed that patients at risk of therapy failure 3month post-therapy included, large thyroid gland prolong antithyroid drug usage and male gender.</p><p> </p>

Increased Risk of Leukemia After Radioactive Iodine Therapy in Patients with Thyroid Cancer: A Nationwide, Population-Based Study in Korea.

The use of radioactive iodine therapy (RAIT) is increasing in thyroid cancer management. The association between RAIT at high doses and leukemia is well known, but studies of this association in a large population are lacking. This study aims to investigate the association between RAIT and leukemia in the context of current practice. Retrospective analysis of a 542,845 person-year (PY) follow-up of thyroid cancer patients was conducted using the Korean National Health Insurance claims database between January 2008 and December 2013. Patients were categorized according to RAIT dose (no RAI; low dose, ≤30 mCi; moderate dose, 31-100 mCi; high dose, 101-150 mCi; and very high dose, >150 mCi). Among 211,360 thyroid cancer patients, 72 (0.03%) patients developed leukemia during follow-up (median 877 days). The cumulative incidence of leukemia per 10(5) person-year (PY) was 9.8 in the no RAI [95% confidence interval (CI) 6.4-14.4]; 6.1 [CI 1.7-15.7] in the low-dose; 8.6 [CI 3.2-18.7] in the moderate-dose; 29.5 [CI 18.3-45.1] in the high-dose; and 20.9 [CI 11.7-34.4] in the very high-dose groups. The hazard ratios were elevated significantly in the high- and very high-dose groups (HR 3.1 and 2.1, respectively, p<0.001) when compared with the no RAI group. RAIT exceeding 100 mCi was strongly associated with the development of leukemia in a nationwide, population-based study, while lower RAIT doses were not. Considering the favorable survival of patients with thyroid cancer and the potential harm of RAIT, physicians need to consider the pros and cons of RAIT when using this treatment option.

Salivary gland dysfunction after radioactive iodine (I-131) therapy in patients following total thyroidectomy: emphasis on radioactive iodine therapy dose

PurposeThe purpose of this study was to retrospectively evaluate symptoms, images of salivary gland dysfunction, and related clinical factors in thyroid cancer patients with total thyroidectomy followed by radioiodine therapy (RIT). MethodsWe included 164 patients who underwent thyroid ultrasonography or contrast-enhanced neck computed tomography more than 6 months later after RIT. Correlation between subjective symptoms and various RIT doses was also evaluated. ResultsSwelling and decreased salivary volume were the most common symptoms and images. RIT dose was the only factor with a positive correlation (P<.001). ConclusionThe dose of RIT should be carefully determined to minimize gland dysfunction.

Stimulated Serum Thyroglobulin Level at the Time of First Dose of Radioactive Iodine Therapy Is the Most Predictive Factor for Therapeutic Failure in Patients With Papillary Thyroid Carcinoma.

To investigate the clinical importance of serum thyroglobulin (Tg) levels just before high-dose I-131 ablation therapy (preablation Tg) for predicting therapeutic failure in patients with papillary thyroid carcinoma (PTC). Patients with PTC (n = 132) undergoing total thyroidectomy followed by the first high-dose I-131 ablation therapy (HI-Rx) were included in this retrospective review. Just before HI-Rx, preablation Tg, anti-Tg antibody, and TSH were measured. The patients were followed up for a mean period of 7months (range 6-23 months) by I-123 whole-body scans (f/u IWBS) and stimulated Tg (f/u Tg). Therapeutic failure was defined by positive f/u IWBS or f/u Tg >2ng/ml. We classified patients into three groups according to the value of preablation Tg (group 1, <1ng/ml; group 2, ≥1 and <10ng/ml; group 3, ≥10ng/ml) and compared clinical variables to therapeutic response. Therapeutic failure was noted in 39 patients (29.5%). On univariate analysis, T stage, tumor size, and preablation Tg were the statistically significant factors that could predict therapeutic failure. After multivariate analysis, preablation Tg was the only independent predictor of therapeutic failure (P < 0.001). The therapeutic failure rate was significantly increased as the preablation Tg level increased (11.3%, 33.3%, and 87.5% in groups 1, 2, and 3, respectively; P < 0.001). Individuals with preablation Tg levels ≥10ng/ml had 25.5 times greater chance of therapeutic failure than those with levels <10ng/ml (95% CI = 5.43-119.60; P < 0.001). A high preablation Tg level is the most significant predictor of therapeutic failure at the time of first HI-Rx in patients with PTC.

Clinical significance of diffuse intrathoracic uptake on post-therapy I-131 scans in thyroid cancer patients.

The purpose of this study was to identify the frequency and possible cause of diffuse intrathoracic uptake on post-therapy I-131 scans in thyroid cancer patients. We retrospectively reviewed 781 post-therapy scans of 755 thyroid cancer patients who underwent total thyroidectomy and radioactive iodine therapy between January and December 2010. Diffuse intrathoracic uptake on post-therapy scans was examined, and clinical patient characteristics including sex, age, regimen for thyroid-stimulating hormone (TSH) stimulation (thyroid hormone withdrawal or recombinant human TSH injection), TSH, thyroglobulin (Tg) and anti-thyroglobulin antibody (anti-Tg Ab) levels, therapeutic dose of radioactive iodine therapy and prior history of radioactive iodine therapy were recorded.Scan findings were correlated with chest CT, chest radiographs, laboratory tests and/or clinical status. Diffuse intrathoracic uptake without evidence of pathologic condition was categorized as indeterminate. The association between clinical characteristics and intrathoracic uptake were analyzed for negative intrathoracic uptake and indeterminate uptake groups. Diffuse intrathoracic uptake on post-therapy scans was demonstrated in 39 out of 755 (5.2%) patients, among which 3 were confirmed as lung metastasis. The 14 patients that showed high Tg or anti-Tg Ab levels were considered to be at risk of having undetected micrometastasis on other imaging modalities. The remaining 22 were indeterminate (2.9%).Upon comparison of negative intrathoracic uptake and indeterminate uptake groups, TSH stimulation by thyroid hormone withdrawal was shown to be significantly correlated with diffuse intrathoracic uptake (p < 0.05). The frequency of diffuse intrathoracic uptake on post-therapy scans was 5.2% and could be seen in thyroid cancer patients with underlying lung metastasis as well as those without definite pathologic condition. In the latter, there was a higher frequency for diffusely increased intrathoracic uptake in those who underwent thyroid hormone withdrawal rather than recombinant human TSH injection.