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It has been reported that Graves' disease (GD) sometimes improves spontaneously during pregnancy, although exacerbation of GD during postpartum period or relapse of hyperthyroidism caused by GD might occur. This study aimed to investigate the incidence of postpartum diagnosis of thyroid eye disease (TED) in relation to thyroid dysfunction. This retrospective cross-sectional study enrolled 11,104 deliveries from the patients with GD between January 2004 and August 2022. Within the 12-month postpartum period, 72 patients (0.65%) were diagnosed with TED. The thyroid function of the 72 patients comprised 9 remission, 13 continued antithyroid medicine, and 50 thyroid dysfunction; 30 newly diagnosed GD, 1 hypothyroidism, and 19 relapse/recurrence of GD. In the 49 patients with thyroid dysfunction, no difference was observed in the median values of thyroid-stimulating hormone (TSH) receptor antibody (TRAb) and TSH receptor stimulating antibody between the TED diagnosis and the development of hyperthyroidism. However, when the patients were classified into the newly developed GD and relapse/recurrence of GD groups, the difference became significant and the TRAb level was high in the newly developed GD (16.1 vs. 5.0 IU/L, p < 0.0001, and 15.0 vs. 6.0 IU/L, p = 0.0003). Thyroid dysfunction preceded TED diagnosis in more than half of the patients and the median time for each event was 6.5 vs. 8.1 months. The active phase TED was observed in 8 of the 72 patients. Of the 72 patients newly diagnosed with TED in postpartum, two-thirds were accompanied by thyroid dysfunction and 8 of them were in active phase.

Agranulocytosis is a serious adverse effect of methimazole (MMI) and propylthiouracil (PTU), and although there have been reports suggesting a dose-dependent incidence in relation to both drugs, the evidence has not been conclusive. The objective of our study was to determine whether the incidences of agranulocytosis induced by MMI and PTU exhibit dose-dependency. The subjects were 27,784 patients with untreated Graves' disease, 22,993 of whom were on an antithyroid drug treatment regimen for more than 90 days. Within this subset, 18,259 patients had been treated with MMI, and 4,734 had been treated with PTU. The incidence of agranulocytosis according to dose in the MMI group was 0.13% at 10 mg/day, 0.20% at 15 mg/day, 0.32% at 20 mg/day, and 0.47% at 30 mg/day, revealing a significant dose-dependent increase. In the PTU group, there were 0 cases of agranulocytosis at doses of 125 mg/day and below, 0.33% at 150 mg/day, 0.31% at 200 mg/day, and 0.81% at 300 mg/day, also revealing a significant dose-dependent increase. The incidence of agranulocytosis at MMI 15 mg and PTU 300 mg, i.e., at the same potency in terms of hormone synthesis inhibition, was 0.20% and 0.81%, respectively, and significantly higher in the PTU group. Our findings confirm a dose-dependent increase in the incidence of agranulocytosis with both drugs, but that at comparable thyroid hormone synthesis inhibitory doses PTU has a considerably higher propensity to induce agranulocytosis than MMI does.

Appropriate administration of anti-inflammatory and immunosuppressive treatment (AIIST) is important for patients with Graves' orbitopathy (GO). This study aimed to clarify the incidence and risk factors for GO treated with AIIST and propose a predictive score, among newly diagnosed Graves' disease (GD) patients in Japan. A total of 1,553 GD patients who were newly diagnosed during the year 2011 were investigated. AIIST included local and/or systemic glucocorticoid administration and retrobulbar irradiation. A multivariable Cox proportional hazards model was used to investigate the risk factors for GO underwent AIIST during medical treatment, including at diagnosis, of GD. Then, a GO score was created by summing each point assigned to risk factors based on their coefficient obtained in the Cox model. AIIST was administered to 107 patients (6.9%). The risk factors and hazard ratios for GO underwent AIIST were: age (per 10 years), 1.32 (95% confidence interval: 1.16-1.50), p < 0.0001; TSH binding inhibitory immunoglobulin (TBII) (per 10 IU/L), 1.33 (1.15-1.54), p = 0.0001; and thyroglobulin antibody (TgAb) negativity, 2.98 (1.96-4.59), p < 0.0001. The GO score, ranging from 0 to 8 points, showed moderate performance (area under the curve: 0.71, cut-off value: 5 points, sensitivity: 0.76, specificity: 0.59, positive predictive value: 0.12, negative predictive value: 0.97). AIIST was performed for patients with active manifestations of GO in 6.9% of newly diagnosed GD patients. The risk factors for GO underwent AIIST were higher age, higher TBII, and TgAb negativity. The GO score based on these factors may be useful in managing GO.

The present study aimed to establish new reference intervals (RIs) for serum free triiodothyronine (fT3), free thyroxine (fT4), and thyroid stimulating hormone (TSH) levels in Japanese children and adolescents aged 4 to 19 years. A total of 2,036 (1,611 girls, 425 boys) participants were included over a 17-year period; they all tested negative for antithyroid antibodies (TgAb, TPOAb) and were found to have no abnormalities on ultrasonography. RIs were determined by nonparametric methods. The results showed that serum fT3 was significantly higher in the 4-15-year-olds than in the 19-year-olds. The serum fT4 was significantly higher in the 4-10-year-olds than in the 19-year-olds. The serum TSH was significantly higher in the 4-12-year-olds than in the 19-year-olds. All of them gradually decreased with age to approximate the adult levels. The upper limit of TSH was lower in those aged 13 to 19 years than in adults. The differences were examined by sex. The serum fT3 was significantly higher in boys than in girls between the ages of 11 and 19 years. The serum fT4 was significantly higher in boys than in girls between the ages of 16 and 19 years. There did not seem to be any sex difference in those under 10 years of age. In conclusion, serum fT3, fT4, and TSH levels in children and adolescents differ from those in adults. It is important to evaluate thyroid function using the new RIs that are appropriate for chronological age.

The effect of potassium iodide (KI) on radioiodine uptake (RAIU) before radioisotope therapy in Graves' disease (GD) patients was investigated. A total of 82 patients who had been treated with KI monotherapy before 24-hour RAIU (24 h RAIU) were evaluated and 354 of those who had been treated with thiamazole (MMI) monotherapy were extracted from the 1,130 GD patients who were identified as having had appropriate iodine restriction based on urinary iodine excretion. Urinary iodine excretion (UIE) <200 μg/day was confirmed in all subjects. Propensity score-matching was performed to identify the difference in 24 h RAIU between the KI group and the MMI group. In addition, multiple regression analysis was performed to evaluate related to 24 h RAIU. Propensity score-matching resulted in 57 matched patients in each group. After matching, 24 h RAIU was still significantly lower in the KI group than in the MMI group (median 53% (interquartile range 47-61%) vs. 63% (56-66%); p = 0.001). In addition, KI monotherapy was weakly negatively correlated with 24 h RAIU, whereas the female sex and FT3 were very weakly positively correlated on multiple regression analysis. The results suggest that KI monotherapy likely suppressed 24 h RAIU more than MMI monotherapy in GD patients with appropriate iodine restriction, given the difference in the mechanism of hormone suppression.

Graves' disease has been reported to affect the clinical features of moyamoya disease (MMD), an occlusion of the circle of Willis. This study aimed to clarify the characteristics of MMD in patients with Graves' disease. This was a single-center, retrospective study. The prevalence and clinical features of MMD patients among all patients with thyroid disease who visited Ito Hospital from January 2005 to December 2019 were evaluated. The relationship between MMD and hyperthyroidism was analyzed in new-onset Graves' disease patients during the same period. Of all 394,422 patients with thyroid disease, 88,180 had Graves' disease, and 40 had MMD with Graves' disease, i.e., the prevalence was 45.36 per 100,000 patients with Graves' disease (0.0454%). The median age at onset of MMD was 39 years (interquartile range, 31-54 years), with a male to female ratio of 1:12. The most common time that MMD was diagnosed was within 1 year after the onset of Graves' disease, in 9 of 40 patients (22.5%), and 19 of 40 patients (47.5%) underwent bypass surgery for MMD. In MMD with Graves' disease, headache was the most frequent symptom, and ischemic types of stroke and bilateral lesions were common. Of 23,347 patients with new-onset Graves' disease, 7 were diagnosed with MMD and the incidence of MMD was 5.94 patients per 100,000 person-years. Most patients developed MMD symptoms during hyperthyroidism. Although MMD is a rare condition, it should be noted that it can occur with Graves' disease.

Although untreated Graves' disease (GD) is associated with a higher risk of cardiac complications and mortality, there is no well-established way to predict the onset of thyrotoxicosis in clinical practice. The aim of this study was to identify important variables that will make it possible to predict GD and thyrotoxicosis (GD + painless thyroiditis (PT)) by using a machine-learning-based model based on complete blood count and standard biochemistry profile data. We identified 19,335 newly diagnosed GD patients, 3,267 PT patients, and 4,159 subjects without any thyroid disease. We built a GD prediction model based on information obtained from subjects regarding sex, age, a complete blood count, and a standard biochemistry profile. We built the model in the training set and evaluated the performance of the model in the test set by using the artificial intelligence software Prediction One. Our machine learning-based model showed high discriminative ability to predict GD in the test set (area under the curve [AUC] 0.99). The main contributing factors to predict GD included age and serum creatinine, total cholesterol, alkaline phosphatase, and total protein levels. We still found high discriminative ability even when we restricted the variables to these five most contributory factors in our prediction model (AUC 0.97) built by using artificial intelligence software showed high GD prediction ability based on information regarding only five factors.

An asymptomatic, 68-year-old Japanese man visited our hospital for further examination of subclinical hypothyroidism. At the first visit, the serum TSH level was markedly elevated (36.6 μIU/mL), but the serum level of free T4 was within the reference interval. Thyroid dysfunction due to dietary iodine excess was initially suspected. However, even after iodine restriction, his thyroid function tests were the same as at the first visit, which suggested false elevation of the TSH level. The TSH levels were compared among three different measurement systems, which showed a similar tendency of TSH elevation above the reference interval, but the different TSH elevation levels among the measurement methods suggested the existence of some interfering substance. Neither serial dilution of the patient's serum nor polyethylene glycol and protein G precipitation tests showed any significant changes in the recovery rate. IgG-bound macro-TSH was ruled out. The TSH peak on gel filtration chromatography was located at a molecular size greater than IgA, which suggested the presence of IgA-bound TSH. After precipitation with Jacalin, which binds specifically to IgA, the TSH level decreased from 30.7 μIU/mL to 2.01 μIU/mL, within the reference interval. Thus, IgA-bound macro-TSH was identified. Macro-TSH is a rare condition in which an immunoglobulin-bound, high-molecular-weight form of TSH results in a false elevation of the serum TSH level. When there is a discrepancy between the results of thyroid function tests and clinical symptoms, and macro-TSH is suspected, it is necessary to know that not only IgG-bound TSH but also IgA-bound TSH could be the cause.

Propylthiouracil (PTU)-induced otitis media with anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (OMAAV) is an extremely rare adverse event associated with anti-thyroid drugs and is not well recognized. A 42-year-old woman with Graves' disease undergoing PTU therapy for 8 years visited our hospital because of earache and congested feeling in her left ear. Blood tests, a computed tomography scan and pure tone audiometry revealed otitis media and moderate mixed hearing impairment. Antibiotics, ear drops with antibiotics and painkillers were administered. However, her earache and hearing loss gradually got worse and symptoms of facial nerve palsy appeared. At several weeks after initiation of the treatment, a high serum level of myeloperoxidase (MPO)-ANCA, 75.6 U/mL, was revealed. After excluding other causes, she was diagnosed with OMAAV. PTU was suspected as the cause of her OMAAV and was immediately discontinued, and prednisolone was started. Hearing impairment in her left ear gradually got better and showed substantial improvement. Facial nerve palsy disappeared. Although PTU-induced OMAAV is an extremely rare disease, it is important to recognize the disease, as delayed treatment can lead to irreversible hearing loss, hypertrophic pachymeningitis, and subarachnoid hemorrhage. When patients taking anti-thyroid drugs, especially PTU, are diagnosed with refractory otitis media or hearing loss, it is possible that OMAAV might be the cause and thus serum ANCA levels should be evaluated.

Activity of Graves' disease (GD) is known to improve during gestation, as values of thyrotropin (TSH) receptor antibody (TRAb) also improve. However, the risk of neonatal hyperthyroidism increases when maternal TRAb values are high in the second to third trimester. A 29-year-old woman who had undergone radioactive iodine (RAI) therapy for GD 10 years earlier visited our hospital at 17 weeks of gestation, showing subclinical hypothyroidism and a positive TRAb value of 2.6 IU/L (reference range, <2.0 IU/L). Thyroid hormone replacement therapy was commenced and thyroid function normalized within 4 weeks, although TRAb was elevated at the time (3.8 IU/L). Prenatal check-up showed normal growth development and no irregularities. At 29 weeks of gestation, serum TRAb was extremely elevated, up to 16.8 IU/L. Since the risk of neonatal hyperthyroidism was of great concern, delivery was planned at an advanced-care medical center. At 38 weeks 5 days of gestation, she delivered a female neonate without any complications, although blood testing of the neonate showed subclinical hyperthyroidism with positive TRAb and TSH receptor stimulating antibody (TSAb). According to the American Thyroid Association guidelines, the TRAb value should be checked in the third trimester if mothers show a TRAb elevation between the initial visit after pregnancy and 18-22 weeks of gestation. However, if the mother has a history of RAI therapy for GD, regardless of thyroid function during gestation, the possibility of TRAb values elevating over time even years after the definitive therapy must be considered.

Radioactive iodine (RAI) therapy has been the mainstay of treatment for papillary thyroid carcinoma (PTC) patients with distant metastasis (DM). Although tyrosine kinase inhibitors (TKIs) were introduced for the treatment of RAI refractory metastatic thyroid carcinoma several years ago, clinical outcomes for PTC patients with DM treated using RAI therapy remain unclear. We retrospectively examined 64 PTC patients (9 men, 55 women) with DM at diagnosis treated using RAI therapy without administration of any kind of chemotherapy or TKIs. Median age of patients was 58 years. Site of DM was the lungs (n = 59), bone (n = 3), and pleural dissemination (n = 2). No patients showed multiple-organ metastases at diagnosis. By the end of the study period, 21 patients had died of PTC. Cause-specific survival rates at 10, 15, and 20 years after initial surgery were 68.2%, 63.6% and 61.1%, respectively. Uni- and multivariate analyses identified age ≥55 years (HR 3.1, p = 0.023), site of DM other than the lungs (HR 13.4, p < 0.0001), and DM with no RAI avidity (HR 5.1, p = 0.0098) as factors independently associated with disease-related death. When analyses were restricted to patients with lung metastasis (n = 59), surgical non-curability was another independent risk factor (HR 5.2, p = 0.0047) in addition to age and RAI avidity. According to risk stratification analysis based on these risk factors, patients with site of DM other than the lungs or with lung metastasis showing ≥2 risk factors among age ≥55 years, DM with no RAI avidity, and surgical non-curability are expected to show higher mortality rates.

The efficacy of potassium iodide (KI) for Graves' disease (GD) has been reported, although few clinical reports have examined the long-term efficacy of treatment. The objective of this study was to investigate the efficacy and limitations of KI treatment for GD. This study enrolled patients newly diagnosed with mild GD, defined as free thyroxine (FT4) <5.0 ng/dL, between July 2014 and June 2016. KI was started at a dose of 50 mg/day, and if FT4 values did not decrease after initiation of treatment, doses were increased to 100 mg/day. Patients for whom thyroid hormone levels could not be controlled with KI at 100 mg/day were regarded as non-responders. Of the 122 patients (13 males, 109 females) included in this study, 71 (58.2%) responded to KI therapy. The remaining 51 patients (41.8%) were non-responders. The median duration required to judge non-responsiveness was 5.9 months. Multiple logistic regression analysis performed on parameters measured at the initial visit indicated FT4 (odds ratio (OR) 2.19, 95% confidence interval (CI) 1.28-3.75; p = 0.0007) and male sex (OR 3.58, 95%CI 1.04-12.3; p = 0.04) were significantly associated with KI responsiveness. Receiver operating characteristic (ROC) curve analysis of the relationship between FT4 and KI responsiveness indicated an FT4 cut-off of 2.76 ng/dL was optimal for differentiating between responders and non-responders. KI therapy was effective and safe for about 60% of patients with mild GD.

The extent of thyroidectomy in Graves' disease remains controversial. In our institution, long-term euthyroidism without thyroxin replacement therapy has been the aim, and it has long been the standard surgical procedure used to treat Graves' disease in many institutions, including our hospital. Based our several clinical studies, it was concluded that subtotal thyroidectomy is not suitable as a standard surgical procedure for the treatment of Graves' disease. In 2009, the surgical strategy for Graves' disease was changed from subtotal thyroidectomy to total thyroidectomy in our hospital. In this study, how surgical complications have changed after this modification was examined. The subjects were 1,476 patients with Graves' disease treated by thyroidectomy between 2006 and 2014. There were 1,119 females and 357 males with a median age of 39 years. A total of 660 patients underwent bilateral subtotal thyroidectomy (ST group), and 816 patients underwent total thyroidectomy (TT group). Both transient hypocalcemia and prolonged hypocalcemia were observed significantly more frequently in the TT group than in the ST group (p < 0.001). Total thyroidectomy was identified as risk factors for prolonged hypocalcemia on multivariate analysis. In conclusion, total thyroidectomy is a reliable and effective therapy for controlling hyperthyroidism in terms of controlling of hyperthyroidism. However, it should be noted that total thyroidectomy resulted in increased rate of prolonged hypocalcemia. Surgeons should try to reduce the surgical complication rate as much as possible.

Lenvatinib is a molecular-targeting agent that was recently approved in Japan for treatment of curatively unresectable, radioactive iodine-refractory, progressive differentiated thyroid cancer (DTC). Because only a few Japanese patients have received lenvatinib in clinical trials, there are limited domestic data on its safety and efficacy or prognostic factors. Therefore, a prospective observational study has been designed to collect safety and efficacy data in at least 300 patients with curatively unresectable DTC receiving lenvatinib therapy (24 mg/day), in order to find predictors of antitumor activity and survival. Patients with progressive curatively unresectable DTC refractory to radioiodine therapy will be enrolled and the primary endpoint will be overall survival. This study is designed to estimate the 95% confidence intervals of the 1-year and 2-year survival rates with a two-sided width of less than 10%. Secondary endpoints will be the time to treatment failure, time to strategy failure, progression-free survival time with clinical progressive disease, response rate, quality of life, safety, and patient reports. The ultimate goal is to obtain information for developing evidence-based guidelines for treatment of DTC, including recommendations on patient selection, dosages, and duration of treatment. This study has been registered with the UMIN Clinical Trials Registry (UMIN000022243).

New insights in thyroid cancer biology propelled the development of targeted therapies as salvage treatment for radioiodine-refractory differentiated thyroid cancer (RR-DTC), and the tyrosine kinase inhibitor (TKI) lenvatinib has recently become available as a new line of therapy for RR-DTC. The aim of this study is to investigate clinical factors related to the efficacy of TKI therapy in recurrent RR-DTC patients and identify the optimal timing for the start of TKI therapy. The subjects consisted of 29 patients with progressive RR-DTC, 9 males and 20 females, median age 66 years. A univariate analysis was conducted in relation to progression free survival (PFS) and overall survival (OS) by the Kaplan-Meier method for the following variables: age, sex, histology of the primary tumor, thyroglobulin doubling time before the start of lenvatinib therapy, site of the target lesions, presence of a tumor-mediated symptom at the start of lenvatinib therapy, and baseline tumor size of the target lesions. Median duration of lenvatinib therapy was 14.7 months and median drug intensity was 9.5 mg. At the time of the data cut-off for the analysis, 9 patients (31.0%) have died of their disease (DOD), and a PR (partial response), SD (stable disease), and PD (progressive disease) were observed in 20 patients (69%), 6 patients (20.7%), 3 patients (10.3%), respectively. Univariate analyses showed that the presence of a symptom was the only factor significantly related to poorer PFS and OS. Clinical benefit of TKI therapy will be possibly limited when the therapy starts after tumor-mediated symptoms appear.

Although advanced thyroid carcinoma patients who cannot be cured by conventional therapy have lacked effective treatment, multitargeted tyrosine kinase inhibitors have recently become available. Phase 3 trials of lenvatinib showed a median time to objective response of 2 (95 % confidence interval (CI) 1.9-3.5) months, demonstrating that shrinks tumors rapidly. The phenomenon of immediate tumor shrink is known as early tumor shrinkage (ETS) which is related to clinical outcome in other malignancies. However, precisely when within 8 weeks lenvatinib starts to affect tumors remains unclear. In tumors near the carotid arteries, trachea, or esophagus, a rapid therapeutic effect can induce fistula formation or arterial bleeding. To prevent such treatment-emergent serious adverse events (SAE), early imaging evaluation seems to be very important. In this study, the point in time when lenvatinib started to shrink tumors was retrospectively investigated. The subjects were 16 patients who started lenvatinib administration between May and August 2015. Tumor size was evaluated by computed tomography (CT) scans frequently within the first 8 weeks according to the Response Evaluation Criteria In Solid Tumors (RECIST) guideline. Initial tumor response was defined as ≥ 10% tumor reduction. Serum thyroglobulin (Tg) level was monitored in 8 differentiated thyroid carcinoma (DTC) without TgAb patients. At the first evaluation, 13 patients (83.3 %) showed tumor reduction and that decreased with time. Thirteen patients (83.3 %) showed >10 % tumor reduction within 8 weeks. In all DTC patients, serum Tg level was markedly decreased. In conclusion, lenvatinib immediately shrinks tumors, the so-called ETS phenomenon. Therefore, careful attention should be paid to fistula formation from the early phase.

Familial dysalbuminemic hyperthyroxinemia (FDH) is an autosomal dominant condition and is the most commonly inherited euthyroid hyperthyroxinemia in Caucasians. However, it is extremely rare in Asian populations. A 30-year-old Japanese woman, who was incidentally found to have apparent thyroid dysfunction, was admitted to our hospital in 2004. She had extremely elevated serum free thyroxine (FT 4 ), moderately elevated free triiodothyronine (FT 3 ), and normal thyroid-stimulating hormone (TSH). Clinical thyroid examination revealed no abnormalities other than small goiter. Anti-thyroglobulin antibody titer was positive, but titers of other anti-thyroid antibodies, including antithyroid peroxidase antibody, TSH receptor antibodies, and thyroid-stimulating antibody, were negative. Levels of FT 3 , FT 4 , and TSH were similar when measured by three different laboratory kits, and FT 4 was still high when measured by equilibrium dialysis. By affinity chromatography, FT 4 , TT 4 , and albumin were extracted to the same fraction, and the levels of FT 4 and TT 4 were extremely high. By combination of reversed phase liquid chromatography and mass spectrometry techniques, the amino acid sequence of human serum albumin was determined. The patient was found to be a heterozygote for p.R218P mutation in the gene for human serum albumin and was diagnosed as FDH. This patient, who harbored the p.R218P mutation in the albumin gene, is the fifth case report of FDH in Japan. This condition is characterized by extremely high serum FT 4 and moderately high serum FT 3 levels. Although rare, FDH should be considered in the differential diagnosis for syndrome of inappropriate secretion of TSH (SITSH) in Japan.

Overt hyperthyroidism is associated with reduced bone density. The extent of restoration of reduced bone density caused by hyperthyroidism in postmenopausal Graves' disease (GD) patients has not fully been investigated. We examined 85 newly diagnosed postmenopausal GD patients, and we measured their serum thyroid hormone levels as well as their bone turnover marker levels and the bone mineral density (BMD) of their lumbar spine (LS), both femoral necks (FN), and left distal radius (DR). We prospectively observed the patients for changes in BMD and bone turnover marker levels during a 24-month period after euthyroidism had been established by ATD treatment. The median age of the subjects was 57 years old (range: 50 to 79). 46 (54.1%) patients had osteoporosis. 42 of the 46 osteoporosis patients had low BMD in the DR. The patients with osteoporosis were significantly older, had a significantly lower BMI, and had significantly higher bone turnover marker levels compared to the normal BMD patients. The best predictor of the BMD in the DR was BMD in the FN (β = 0.40, p < 0.0001). A total of 42 patients were followed up for 24 months after attainment of euthyroidism, and 19 of them were osteoporosis at the first visit. The BMD of the 19 osteoporotic patients had increased by 4.9% in the LS, 11.9% in the FN, and 9.3% in the DR at 24 months. After maintaining a euthyroid state for 24 months by means of ATD treatment, 26% of the osteoporotic patients had recovered from osteoporosis.

Differentiated thyroid carcinoma (DTC) is generally indolent in nature and, even though it metastasizes to distant organs, the prognosis is normally excellent. In contrast, the overall survival (OS) of patients with radioactive iodine (RAI)-refractory and progressive metastases is dire, because no effective therapies have been available to control the metastatic lesions. However, recently, administration of tyrosine-kinase inhibitors (TKIs) has become a new line of therapy for RAI-refractory and progressive metastases. Previous studies have reported significant improvement regarding the progression-free survival rates of patients with metastatic lesions. However, TKIs cause various severe adverse events (AEs) that damage patients' quality of life and can even be life-threatening. Additionally, metastatic lesions may progress significantly after stopping TKI therapy. Therefore, it is difficult to determine who is a candidate for TKI therapy, as well as how and when physicians start and stop the therapy. The present review, created by Committee of pharmacological therapy for thyroid cancer of the Japanese Society of Thyroid Surgery (JSTS) and the Japan Association of Endocrine Surgeons (JAES) describes how to appropriately use TKIs by describing what we do and do not know about treatment using TKIs.

The aim of this study was to clarify the histopathological features of anaplastic thyroid carcinoma in patients who achieved long-term survival. We reviewed 88 anaplastic thyroid carcinoma cases in which the patient survived less than 3 months (short-term survival), and 68 anaplastic thyroid carcinoma cases in which the patient survived more than one year (long-term survival) from the database of the Anaplastic Thyroid Carcinoma Research Consortium of Japan. We examined these cases both histologically and immunohistochemically. Six (6.8%) short-term survival cases and 27 (39.7%) long-term survival cases were considered not to be anaplastic thyroid carcinoma after central review. Of these, 12 were revised to papillary carcinoma with squamous cell carcinoma. In cases without chemotherapy, long-term survival was significantly more common if there was a pre-existing tumor, epithelial growth, or lymphocytic infiltration, and short-term survival was more common if neutrophilic infiltration was present. In cases with chemotherapy, long-term survival was significantly more common if epithelial growth or a squamous cell carcinoma component was present, whereas short-term survival was more common in cases with rhabdoid cells. Immunohistochemical results were not related to survival. Some long-term survival cases showed histological findings other than those typically associated with anaplastic thyroid carcinoma. The presence of a pre-existing tumor, epithelial growth, a squamous cell carcinoma component, no neutrophilic infiltration and lymphocytic infiltration may therefore be favorable prognostic factors in anaplastic thyroid carcinoma.

Metastatic differentiated thyroid carcinoma (DTC) is an uncommon cause of malignant pleural effusion (MPE) and the characteristics and clinical course have been rarely described. Herein, we report a retrospective review of the clinical course of 18 patients (15 women and 3 men) with MPE from DTC who underwent treatment at our institution between January 2005 and December 2014. MPE from DTC was diagnosed based on cytology and/or level of thyroglobulin in the pleural fluid. Pathologically, papillary carcinoma was found in 16 patients and follicular carcinoma in 2 patients. Median ages at initial diagnosis of DTC and MPE were 64 years (range, 22-79) and 74 years (range, 39-86), respectively. All patients showed radiologically apparent lung metastases, with MPE developing after 0-212 months (median, 25). In 16 patients (88.9%), other coexistent distant metastases at the time of MPE diagnosis were found in the bone (n = 10), brain (n = 5), and skin (n = 2). All patients were treated conservatively with palliative thoracentesis or chest tube drainage with or without pleurodesis. Recurrent MPE after treatment was seen in 9 patients; discharge to home health care after treatment for MPE was possible for 14 patients. The overall survival after initial diagnosis varied considerably from 14 months to 37 years, but the median survival after appearance of MPE was 10 months (range, 1-28). Systemic therapy for iodine-resistant recurrent thyroid disease may need to be considered as a treatment option for patients with MPE.

In the event of a nuclear power plant accident, prophylactic administration of potassium iodide (KI) is recommended to prevent thyroid damage due to uptake of radioiodine. To assess the inhibitory effect of low-dose inorganic iodine on thyroidal radioactive iodine uptake (RAIU) in healthy adults without dietary iodine restriction, single or repeated doses of 10 mg inorganic iodine solution were given to 22 Japanese volunteers, 18 men and 4 women with the mean age of 35.7 years, between 2011 and 2013. Changes in urinary iodine excretion, thyroid function and 24-hour RAIU were also evaluated. The median 24-hour RAIU without iodine restriction was 13% (range, 5-26%). A single-dose of 10 mg inorganic iodine suppressed the median 24-hour RAIU measured one hour after iodine administration to 3% (range, 1-7 %) and, in 90.9% of 22 participants their 24-hour RAIU was < 5%. For seven participants given 10 mg of inorganic iodine daily for 14 days, the median 24-hour RAIU measured at 24 hours after the last administration of iodine was 6% (range, 2-12%), although the inhibitory effect was diminished in two participants. Serum thyroid stimulating hormone concentration was slightly elevated in three participants without decreased serum FT3 and FT4 levels. We conclude that a single-dose of 10 mg inorganic iodine is sufficient to inhibit RAIU in adults, although the inhibitory effect of repeated-dose on RAIU is diminished when KI is given once daily. The dose, duration or interval of iodine administration should be evaluated in iodine-sufficient regions in a future.

Gestational transient thyrotoxicosis (GTT) is defined as transient thyrotoxicosis caused by the stimulating effect of human chorionic gonadotropin (hCG) during pregnancy. We attempted to identify the serum hCG level that causes GTT, and we compared the serum hCG levels and thyroid hormone levels of GTT patients according to whether they had a background of thyroid disease. We also evaluated serum hCG as a parameter for differentiating between active Graves' disease (GD) and GTT. We reviewed the 135 cases of pregnant women who came to our hospital to be evaluated for thyrotoxicosis during their 7th to 14th week of pregnancy, and their serum hCG level was measured at that time. Among the 135 pregnant women with thyrotoxicosis; 103 of the women had GTT, and the other 32 women had active GD. There were no correlations between their serum hCG levels and free thyroid hormone levels. There were no significant differences in thyroid hormone levels or hCG levels among the GTT groups with different thyroid disease backgrounds; i.e., the GTT group without thyroid disease, GTT group with chronic thyroiditis, GTT group with non-functioning thyroid nodules, and GTT group with GD in remission. The serum hCG level of the GTT group was significantly higher than in the active GD group, but it was not a good parameter for differentiating between the two groups. The FT3/FT4 ratio of the active GD was significantly higher than in GTT group, and was a better parameter for differentiation.

Follicular thyroid carcinoma (FTC) usually has a good prognosis unless there is distant metastasis (DM). In this retrospective study we evaluated the outcome of FTC patients with DM and attempted to identify prognostic factors. The subjects of this study were the 106 of FTC patients who underwent thyroidectomy at our hospital between 1989 and 2010 who had been diagnosed with DM at presentation or had developed DM after the initial surgery. Their cumulative cause-specific survival (CSS) rate from diagnosis of DM to date of last follow-up was calculated by the Kaplan-Meier method. Prognostic factors were identified by univariate analysis (the log-rank test) and multivariate analysis (Cox's proportional hazards model). The site of the DM was the lung in 36 patients, bone in 33 patients, both lung and bone in 28 patients and other sites in 9 patients. During the follow-up period, 22 patients died of their disease. The DMs were treated by radioactive iodine (RI) therapy in 80 patients, by surgical treatment in 36 patients and by external beam radiation therapy (EBRT) in 27 patients. The CSS rates at 5, 10, and 15 years after the first DM was diagnosed were 82.2%, 63.8%, and 23.9%, respectively. Univariate analyses and multivariate analysis identified age at diagnosis of DM and primary tumor size as significant factors related to CSS. In this study, we could not show RI therapy, EBRT or surgical treatment for DM had an impact on the outcome.

Up until now there have been no promising drugs for the treatment of advanced thyroid cancer, but the development of novel therapeutic agents is now anticipated as a result of the advent of molecular targeted drugs that inhibit tumor growth signals or angiogenesis. Against a background in which the development of numerous molecular targeted drugs for advanced thyroid cancer is being pursued worldwide, the development of sorafenib, vandetanib, and lenvatinib is currently also under way in Japan. All three of these compounds are undergoing phase 3 trials or have been approved abroad, and because they are in the final stage of development in Japan, they are expected to be introduced in clinical settings in the near future. After they have been introduced, it will be necessary to understand the differences between these compounds and to administer them to patients appropriately.

Following the accident at the Fukushima Daiichi Nuclear Power Station which occurred on March 11, 2011 due to the Eastern Japan Great Earthquake (the Accident), there have been concerns over elevation of the risk of thyroid cancer among children due to internal exposure to radioactive iodine. In Fukushima Prefecture, screening of children with thyroid ultrasonography has been carried out, yielding numerous findings, suggesting a possible influence from the Accident. We report thyroid ultrasonographic findings, used by similar device at Fukushima Prefecture's study, at Ito-hospital. Of the 2721 children aged 15 or less who visited our hospital between January 2005 and March 2013, 1214 children (330 boys and 884 girls; median age, 12; range of age, 4-15) were covered by evaluation of thyroid ultrasonographic findings, excluding children known in advance to have thyroid disease on the basis of disease history, palpation and blood tests. Among these 1214 children, 709 children (58.4%) were found cysts (≤ 5 mm in 665 cases) by ultrasonography, 43 children (3.5%) were found nodules (≤ 5 mm in 18 cases) and 9 children (5.2%) were found an intrathyroid ectopic thymus. Analysis of the data before and after the Accident using the same device, involving age adjustment on the basis of the standard population in 2010, showed no difference in the incidence rate of cysts or nodules. In children examined, the incidence rate of cyst formation (particularly ≤ 5 mm) was higher, and there was no difference in the incidence rate of cysts or nodules between the pre- and post-accident period.

Fine-needle aspiration biopsy cytology (FNABC) and ultrasonography (US) play an important role in differentiating benign thyroid nodules from malignant nodules. We retrospectively investigated the prevalence of follicular thyroid carcinoma (FTC) in patients with thyroid nodules whose FNABC and US readings were not malignant before thyroidectomy. Between 2007 and 2008, 3333 patients underwent thyroidectomy at our institution, and the 737 of them who had thyroid nodule that had been diagnosed as hyperplastic nodule or follicular tumor by FNABC and US preoperatively were the subjects in this study. Postoperative histopathology showed hyperplastic nodule in 416 patients, follicular adenoma in 200 patients, FTC in 99 patients, and other disease in 22 patients. By FNABC, 34 (6.7%) of the 505 patients with diagnosis as benign and 65 (28%) of the 232 patients with diagnosis as indeterminate, were diagnosed as having FTC. The diagnosis was FTC in 56 (9.6%) of the 582 patients with a preoperative diagnosis of hyperplastic nodule by US and 43 (27.7%) of the 155 patients with a diagnosis of follicular tumor by US. The diagnosis of FTC was made in 21 (4.8%) of 438 patients who were concurrently diagnosed as benign by FNABC and as hyperplastic nodule by US, and in 30 (34.1%) of 88 patients who were diagnosed as indeterminate by FNABC and follicular tumor by US. FNABC has been the mainstay for the preoperative evaluation of thyroid nodule. The results of this study showed that US can also be a useful tool for diagnosing FTC.

The extent of thyroidectomy in Graves' disease is still a matter of controversy. Subtotal thyroidectomy has been used as the standard surgical procedure for Graves' disease in Japan, but high hyperthyroidism relapse rates have been reported. We retrospectively studied serial changes in the thyroid function Graves' disease patients after they had been treated by subtotal thyroidectomy and assessed whether subtotal thyroidectomy should be recommended as the standard surgical procedure for the treatment of Graves' disease. The subjects were 478 Graves' disease patients who underwent subtotal thyroidectomy at our institution between 1994 and 1997 and were followed up on a regular basis, and their thyroid function 2-3 years after surgery (the early period) and 8-10 years after surgery (the late period) was evaluated and compared. The evaluations in the late period showed that 57% of the euthyroid patients in the early period remained euthyroid, 30% had developed a relapse of hyperthyroidism, and 13 % had become hypothyroid. Approximately 80% of the patients who were overtly hyperthyroid or overtly hypothyroid in the early period remained so in the late period. During the entire periods 47 patients had subclinical hyperthyroidism and were followed up without any postoperative medication. Twenty (42.6%) of them developed overt hyperthyroidism, 11 (23.4%) experienced a spontaneous remission, and 16 (34%) continued to be subclinically hyperthyroid. Because thyroid function after subtotal thyroidectomy is unstable and reduces quality of life, subtotal thyroidectomy is concluded not to be suitable as a standard surgical procedure for the treatment of Graves' disease.

We analyzed the utility of intraoperative parathyroid hormone (IOPTH) monitoring in minimally invasive surgery for primary hyperparathyroidism (pHPT). The subjects were the 167 consecutive patients with pHPT performed initial operation with or without IOPTH between January 2000 and December 2006. Patients were divided into 2 groups. A group who underwent surgery without IOPTH monitoring (Group 1; n=87), and a group who underwent surgery with IOPTH monitoring (Group 2; n=80), in which IOPTH was measured at 5, 10, 15 minutes after excision of the abnormal parathyroid gland. Criterion for evaluation as a cure was a drop in intact PTH level of 50% or more from the preoperative baseline value. The overall cure rate in Group 1 was 93.1%. An enlarged parathyroid gland that was consistent with the results of a preoperative imaging study was found in 84 patients (96.6%). The overall cure rate in Group 2 was 97.5%. In 7 of the patients, there was no drop of 50% or more at any of the 3 points in time measured. Two of these patients were found to have had double adenomas, one on each side, during the initial surgery. Three others were eucalcemic and had normal intact PTH values after surgery, and the remaining 2 patients had persistent disease. Although preoperative localization studies are accurate and essential, IOPTH monitoring improves the cure rate of minimally invasive parathyroidectomy. IOPTH monitoring is a valuable adjunct to achieve adequate intraoperative decision-making, recognizing and resecting additional image-negative hyperfunctioning lesions.

The extent of thyroidectomy in Graves' disease is still controversial. In our institution, long term euthyroidism without thyroxine replacement therapy has been aimed and, thus, subtotal thyroidectomy has been employed. We prospectively studied whether the surgical outcome was improved by a strategy of leaving smaller thyroid remnants. Between 1989 and 1998, 1897 patients with Graves' disease were treated by subtotal thyroidectomy and their thyroid function could be determined 2 to 3 years after thyroidectomy. The 10-year period was divided into 3 parts, '89-'91 (Period 1, n = 690), '92-'94 (Period 2, n = 587) and '95-'98 (Period 3, n = 620). Different maximum thyroid remnant sizes were prospectively established for each period: up to 7 g left in Period 1, up to 6 g in Period 2 and up to 5 g in Period 3. Thyroid function 2 to 3 years after thyroidectomy and the occurrence of surgical complications were compared among the three groups. The relapse rate for Period 1, Period 2, and Period 3 was 14.1%, 12.6%, and 10.9%, respectively, and the rate of euthyroidism decreased and rate of hypothyroidism increased from period to period. Surgical complications increased in Periods 2 and 3. For preventing relapse, the strategy of reducing the thyroid remnant is effective. Subtotal thyroidectomy leaving 3-4 g remnant tissue is a suitable surgical option for Graves' disease.

Recombinant human TSH (rhTSH) brought revolutionary change in the management of patients with differentiated thyroid cancer since it was first approved for clinical use in the United States and Europe. Follow-up management of differentiated thyroid cancer is based on the detection of recurrent or residual cancer, traditionally achieved by measurement of serum thyroglobulin level and various imaging techniques including 131I whole body scan. Previously, TSH stimulation was achieved only by induction of hypothyroidism following withdrawal of thyroid hormone. However, hypothyroidism is uncomfortable and is association with a reduction in quality of life. RhTSH can provide elevated TSH without making patients hypothyroid. In the United States and Europe, rhTSH is approved for use only in monitoring of differentiated thyroid cancer. In this article, we reviewed the role of rhTSH in the diagnosis and management of differentiated thyroid cancer.