Comparison of pathophysiology in subclinical hyperthyroidism with different etiologies.

Subclinical hyperthyroidism (SHyper) is defined as normal levels of free thyroxine (fT4) and free triiodothyronine (fT3) with suppressed levels of TSH. Previous studies have reported the individual pathophysiology of endogenous SHyper patients and athyreotic patients receiving TSH suppression therapy with levothyroxine; however, apparently no studies have compared the two conditions. Five-hundred-forty untreated endogenous SHyper patients and 1,024 patients receiving TSH suppression therapy who underwent total thyroidectomy for papillary thyroid carcinoma were sampled. Thyroid hormone profiles and peripheral indices related to thyrotoxicosis were investigated in endogenous SHyper patients, athyreotic patients receiving TSH suppression therapy, and healthy participants. Endogenous SHyper patients showed significantly higher thyroid hormone levels (fT4 [p < 0.001] and fT3 [p < 0.001]), and peripheral indices showed a significant tendency towards thyrotoxicosis (strong TSH suppression: alkaline phosphatase [ALP, p < 0.001], creatinine [Cre, p < 0.001], pulse rate [p < 0.05]; and mild TSH suppression: Cre [p < 0.05]) than healthy participants. In contrast, athyreotic patients receiving TSH suppression therapy showed a significant tendency towards thyrotoxicosis than healthy participants only when TSH was strongly suppressed (fT3 [p < 0.001] and Cre [p < 0.001]). Endogenous SHyper patients showed significantly higher fT3 levels (p < 0.001) than athyreotic patients receiving TSH suppression therapy; however, there was a significant tendency towards thyrotoxicosis only when TSH was strongly suppressed (ALP [p < 0.05] and pulse rate [p < 0.05]). The effects of endogenous SHyper and TSH suppression therapy on target organ function are different. Although the serum thyroid hormone profile is similar to that of the thyrotoxic state, athyreotic patients receiving TSH suppression therapy with mildly suppressed serum TSH levels are not thyrotoxic.

Tumor volume-doubling rate is negatively associated with patient age in papillary thyroid microcarcinomas under active surveillance.

BACKGROUND: Active surveillance of low-risk papillary thyroid microcarcinomas has gained popularity worldwide as a management strategy. We previously reported that young age was associated with tumor enlargement by ≥3 mm. Here, we used the tumor volume-doubling rate to study the age-related tumor volume dynamics of papillary thyroid microcarcinomas under active surveillance. METHODS: Between 2005 and 2019, 2,896 patients diagnosed with low-risk papillary thyroid microcarcinomas underwent active surveillance. We excluded patients who underwent ultrasound examination fewer than 4 times, had coexisting Graves' disease, or were treated with levothyroxine at the time of diagnosis, and we enrolled 2,129 patients for this study. We divided them into 3 subsets based on the age at diagnosis: young (<40 years), middle-aged (40-59 years), and elderly (≥60 years). The tumor volume-doubling rate was calculated based on ultrasound-derived tumor sizes and the respective examination date for each patient. RESULTS: Overall, 140 patients (6.6%) had moderate or rapid growth (tumor volume-doubling rate ≥0.3/year), and the incidence significantly decreased with advanced age (P < .01): 11.3%, 7.1%, and 5.0% in the young, middle-aged, and elderly groups, respectively. Tumor regression (tumor volume-doubling rate <0/year) was detected in 1,200 patients (56.4%), and the incidence significantly increased with age (P < .01): 44.6%, 55.3%, and 60.0% in the young, middle-aged, and elderly groups, respectively. On multivariate analysis, both the ≥60 years and 40 to 59 years age groups were independent negative predictors of papillary thyroid microcarcinoma enlargement and positive predictors of tumor regression. CONCLUSION: Tumor volume-doubling rate analysis demonstrated that the incidence of tumor enlargement decreased and that of tumor regression increased with advancing age in patients with papillary thyroid microcarcinomas.

Active Surveillance Outcomes of Patients with Low-Risk Papillary Thyroid Microcarcinoma According to Levothyroxine Treatment Status.

Background: During active surveillance (AS), serum thyrotropin (TSH) levels may affect papillary thyroid microcarcinoma (PTMC) progression. We investigated AS outcomes according to whether levothyroxine (LT4) treatment was administered. Patients and Methods: From 2005 to 2019, 2896 patients with low-risk PTMC underwent AS. Of these, 2509 patients were included: 2187 patients did not receive LT4 at diagnosis (group I), 1935 patients did not receive LT4 during AS (group IA), and 252 patients started LT4 during AS (group IB). The remaining 322 patients were administered LT4 before or at diagnosis (group II). The tumor volume doubling rate (TVDR) and tumor size based on ultrasound examination results and time-weighted detailed TSH scores were calculated. Disease progression was defined as tumor enlargement ≥3 mm and/or the appearance of novel lymph node metastasis. Results: At diagnosis, group II had more high-risk features, such as younger age and larger tumors, than group I. However, group II had a lower disease progression rate (2.9% at 10 years) than group I (6.1%) (p = 0.091). The disease progression rate of group IB (13.8% at 10 years) was significantly higher than that of groups IA (5.0%) and II (2.9%) (p < 0.01). The TVDR of group IB before LT4 administration was significantly higher than that of groups IA and II (0.095 per year, -0.0085 per year, and -0.057 per year, respectively; p < 0.01), suggesting that patients with progression signs during AS were selectively prescribed LT4. The time-weighted detailed TSH score of group IB significantly decreased after LT4 administration compared with those before administration (3.35 and 3.05, respectively; p < 0.01). The TVDR also decreased from 0.13 per year to 0.036 per year (p = 0.08). The proportions of patients with rapid or moderate growth decreased significantly after LT4 (from 26.8% to 12.5%, p < 0.01). A multivariable analysis revealed group IB status was independently associated with disease progression (odds ratio [OR] = 3.42 [CI 2.15-5.44], p < 0.01), whereas age ≥40 years and <60 years and age ≥60 years were independently negatively associated with this outcome (OR = 0.23 [CI 0.14-0.38, p < 0.01 and OR = 0.16 [CI 0.10-0.27], p < 0.01). Conclusion: LT4 treatment may be associated with decreased tumor growth during AS of PTMC, but further confirmatory research is needed.

Outcomes of immediate surgery for low-risk papillary thyroid microcarcinoma in patients with or without risky features at surgery.

Active surveillance (AS) is an accepted management option for patients with low-risk papillary thyroid microcarcinoma (PTMC), although some patients undergo immediate surgery (IS). At surgery, patients may have risky features such as adhesion or invasion to the adjacent organs. The surgical outcomes of this subset of patients are unknown. Here, we investigated the surgical and oncological outcomes of these patients in comparison with others. Between 2005 and 2019, 4,635 patients were diagnosed with low-risk PTMC at our institute. Of these, 1,739 patients underwent IS. In total, 114 patients had risky features at surgery (risky feature group), while the remaining 1,625 did not (no-risky feature group). The median follow-up periods in the risky and no-risky feature groups were 8.5 and 7.6 years, respectively. The risky feature group had higher incidences of tracheal invasion (8.8%), recurrent laryngeal nerve invasion (RLN) (7.9%), and permanent vocal cord paralysis postoperatively (10.0%) and higher frequency of pathological lateral lymph node metastasis (6.1%) than the no-risky feature group (0%, 0%, and 0.2%, and 0%, respectively [p < 0.01]). However, unexpectedly, the former had a lower incidence of high Ki-67 labeling index (1.1%) and lower locoregional recurrence rate (0%) than the latter (8.3% and 0.7, respectively [p < 0.01], not calculable). None of the groups developed distant metastasis or died of the disease. The risky feature group required resection of the trachea and/or the RLN more often than the no-risky feature group. However, unexpectedly, the tumor growth activity in the risky feature group was low, and their oncological outcome was excellent.

Active surveillance is an excellent management technique for identifying patients with progressive low-risk papillary thyroid microcarcinoma requiring surgical treatment.

Although the outcomes of active surveillance (AS) for low-risk papillary thyroid microcarcinoma (PTMC) are generally excellent, some patients undergo conversion surgery for various reasons, including disease progression. We studied the outcomes of PTMC patients who underwent AS, who underwent conversion surgery after AS, and who underwent immediate surgery. Between 2005 and 2019, 4,635 patients were diagnosed with low-risk cT1aN0M0 PTMC at Kuma Hospital: 2,896 opted for AS (AS group) and 1,739 underwent immediate surgery (Surgery group). In the AS group, 242 patients underwent conversion surgery (Conversion group): 72 owing to disease progression (Conversion-prog group) and 170 for other reasons (Conversion-non-prog group). Of the 1,739 patients in the Surgery group, 1,625 had no high-risk features (Surgery-low-risk group). Locoregional recurrence (LRR) occurred in 9, 1, 1, and 0 patient in the Surgery-low-risk group, the Conversion-prog group, the AS group, and the Conversion-non-prog group, respectively. The LRR rate of the AS group was significantly lower than that of the Surgery-low-risk group (0.1% vs. 0.7% at 10 years, p = 0.006). Additionally, the LRR rate of the Conversion group (0.6% at 10 years, p = 0.741) and that of the Conversion-prog group (3.3% at 10 years, p = 0.103) did not significantly differ from the LRR of the Surgery-low-risk group. As the postoperative prognosis of patients with progressive PTMC who underwent conversion surgery did not significantly differ from that of patients who underwent immediate surgery, we think that AS may have resulted in efficient identification of the small proportion of patients with progressive PTMC that require surgical treatment.

Comparison of Postoperative Unfavorable Events in Patients with Low-Risk Papillary Thyroid Carcinoma: Immediate Surgery Versus Conversion Surgery Following Active Surveillance.

Background: Active surveillance (AS) for low-risk papillary thyroid microcarcinoma (PTMC) was initiated at Kuma Hospital in 1993 and has gradually spread worldwide. We previously demonstrated that AS is associated with a much lower incidence of unfavorable events than immediate surgery (IS). However, conversion surgery (CS) raises concerns about increased surgical complications due to advanced disease. In this study, we conducted a comparative analysis of unfavorable events after IS and CS. Methods: Between 2005 and 2019, 4635 patients clinically diagnosed with low-risk PTMC at Kuma Hospital were enrolled. Of these, 2896 underwent AS (AS group), and the remaining 1739 underwent IS (IS group). To date, 242 patients (0.8%) in the AS group have undergone CS for various reasons (CS group). Results: The incidence of unfavorable events, such as levothyroxine administration after surgery, postoperative hematoma, transient/persistent hypoparathyroidism, and transient/persistent vocal cord paralysis, did not differ between the CS and IS groups. None of the patients in the CS group had permanent vocal cord paralysis; however, this occurred in 15 patients (0.9%) in the IS group and was caused by accidental injury in 4 patients and carcinoma invasion in 11 patients. The incidence of surgery, levothyroxine administration, postoperative hematoma, transient/permanent hypoparathyroidism, and vocal cord paralysis was significantly higher (p < 0.001) in the IS group than in the AS group. There were no differences in the incidence of lymph node recurrence and overall mortality between the AS and IS groups. None of the patients in the AS and IS groups showed distant metastasis or died from thyroid carcinoma. Conclusions: There were no differences in the incidence of unfavorable events between the CS group and the IS group. Although none of the CS and AS groups had permanent vocal cord paralysis, accidental injury of the recurrent laryngeal nerve occurred in four patients (0.2%) in the IS group. The IS group had a significantly higher incidence of unfavorable events than the AS group. The prognoses of patients in both the AS and IS groups were excellent. Therefore, we recommend AS as the first-line management for low-risk PTMC.

Development and preliminary validation of a machine learning system for thyroid dysfunction diagnosis based on routine laboratory tests.

Background: Approximately 2.4 million patients in Japan would benefit from treatment for thyroid disease, including Graves' disease and Hashimoto's disease. However, only 450,000 of them are receiving treatment, and many patients with thyroid dysfunction remain largely overlooked. In this retrospective study, we aimed to develop and conduct preliminary testing on a machine learning method for screening patients with hyperthyroidism and hypothyroidism who would benefit from prompt medical treatment. Methods: We collected electronic medical records and medical checkup data from four hospitals in Japan. We applied four machine learning algorithms to construct classification models to distinguish patients with hyperthyroidism and hypothyroidism from control subjects using routine laboratory tests. Performance evaluation metrics such as sensitivity, specificity, and the area under receiver operating characteristic (AUROC) were obtained. Techniques such as feature importance were further applied to understand the contribution of each feature to the machine learning output. Results: The results of cross-validation and external evaluation indicated that we achieved high classification accuracies (AUROC = 93.8% for hyperthyroidism model and AUROC = 90.9% for hypothyroidism model). Serum creatinine (S-Cr), mean corpuscular volume (MCV), and total cholesterol were the three features that were most strongly correlated with the hyperthyroidism model, and S-Cr, lactic acid dehydrogenase (LDH), and total cholesterol were correlated with the hypothyroidism model. Conclusions: We demonstrated the potential of machine learning approaches for diagnosing the presence of thyroid dysfunction from routine laboratory tests. Further validation, including prospective clinical studies, is necessary prior to application of our method in the clinic.

Proportion of serum thyroid hormone concentrations within the reference ranges in athyreotic patients on levothyroxine monotherapy: a retrospective study.

BACKGROUND: In patients receiving thyroid-stimulating hormone (TSH) suppressive therapy with levothyroxine (LT4) after total thyroidectomy for thyroid cancer, thyroid function tests should be performed to adjust the LT4 dose. Specifically, serum TSH concentrations are commonly measured because TSH suppression is necessary according to thyroid cancer risk. The aim of the present study was to elucidate whether free thyroxine (FT4) or free triiodothyronine (FT3) indicates better for adjusting the dose in athyreotic patients on LT4 monotherapy after total thyroidectomy. METHODS: We retrospectively studied the compatibility of free thyroid hormone (FT4 and FT3) concentrations with reference ranges in athyreotic patients on LT4 monotherapy after total thyroidectomy. RESULTS: We identified 2210 consecutive patients from their medical records. Of these patients, 250 had both FT4 and FT3 concentrations in addition to TSH. Two hundred seven had serum TSH concentrations below the reference range (0.5-5.0 µIU/mL), while 43 had them within the reference range. In the 207 patients with TSH concentrations below the reference range, 61 patients (29.5%) had FT4 concentrations within the reference range (0.9-1.7 ng/dL) and 146 patients (70.5%) had FT4 concentrations above the reference range. In contrast, 10 patients (4.8%) had FT3 concentrations below the reference range (2.3-4.0 pg/mL) and 8 (3.9%) had FT3 concentrations above the reference range; 189 patients (91.3%) had concentrations within the reference range. Of the 43 patients with TSH concentrations within the reference range, 25 (58.1%) had FT4 concentrations within the reference range and 18 (41.9%) had FT4 concentrations above the reference range. While, 11 patients (25.6%) had FT3 concentrations below the reference range and one (2.3%) had FT3 concentrations above the reference range; hence, 31 patients (72.1%) had FT3 concentrations within the reference range. CONCLUSION: This study showed that measuring FT3 concentrations rather than FT4 concentrations as the subsequent parameter of thyroid function might be more useful for disease management in terms of the proportion of serum thyroid hormone concentrations within the reference ranges. Furthermore, FT3 measurement could be useful in providing more detailed treatments, including avoiding more aggressive TSH suppressive therapy and identifying the presence of low T3 syndrome in the background.

Criteria for follow-up of thyroid nodules diagnosed as follicular neoplasm without molecular testing - The experience of a high-volume thyroid centre in Japan.

BACKGROUND: Clinical management of follicular neoplasms (FNs) using molecular testing of thyroid-aspirated materials is not routinely performed in Japan. This article aims to identify low-risk FN nodules that can be followed up without molecular testing. METHODS: The relationship between preoperative findings, factors influencing surgical decision, and the risk of malignancy (ROM) was examined in 356 thyroid nodules with cytological diagnosis of FN at Kuma Hospital from January to December 2020. RESULTS: ROMs of FN with cytology results favouring malignancy (41.2%) were significantly higher than those favouring benign (7.7%) or borderline (8.2%) (p < .001). Moreover, ROMs of FN with ultrasonography results of high suspicion (54.5%) were significantly higher than those with low (4.5%) or intermediate suspicion (0%) (p < .0001). There was a large difference in overall ROM in tumours bordering 30 mm in size (<30 mm; 3.6%, ≥30 mm; 20.0%). ROMs of FNs with a tumour volume doubling rate (TVDR) of 1.0/year or more (28.6%) were higher than those of FNs with a lower TVDR (9.9%) (p < .05). The ROMs of FNs with or without one or more of the following four findings suggestive of malignancy: cytological findings favouring malignancy, ultrasonography findings of high suspicion, tumour size ≥30 mm, and TV-DR ≥1.0/year, were 14.6% and 1.0%, respectively. CONCLUSION: FNs with no cytological findings favouring malignancy, no ultrasonography findings of high suspicion, tumour size <30 mm and TV-DR <1.0/year, are considered low risk and can be followed up without the need for molecular testing.

Observational management of papillary microcarcinoma appearing in the remnant thyroid after hemithyroidectomy.

Active surveillance for papillary thyroid microcarcinomas (PTMCs) initiated in Japan is becoming adopted worldwide as a management option. However, it remains unclear how to manage newly appearing PTMCs in the remnant thyroid after hemithyroidectomy. We investigated the outcomes of similar observational management (OM) for PTMCs appearing in the remnant thyroid after hemithyroidectomy for papillary thyroid carcinoma (PTC) and benign thyroid nodules. Eighty-three patients were newly diagnosed with PTMC in the remnant thyroid between January 1998 and March 2017. Of these, 42 patients underwent OM with >3 times ultrasound examinations. Their initial diagnoses were PTC (initially malignant group) in 37 patients and benign nodule (initially benign group) in 5 patients. We calculated the tumor volume doubling rate (TV-DR) during OM for each PTMC. The TV-DR (/year) was <-0.1, -0.1-0.1, 0.1-0.5, and >0.5 in 12, 19, 5, and 6 patients, respectively. The TV-DRs in both groups did not statistically differ, but six patients (16%) in the initially malignant group showed moderate growth (TV-DR >0.5/year). They underwent conversion surgery and none of them had further recurrence. The remaining 36 patients retained OM without disease progression. The TV-DR in the initially malignant group was not significantly associated with patients' backgrounds or their initial clinicopathological features. None of the patients in this study showed distant metastases/recurrences or died of thyroid carcinoma. Although a portion of PTMCs appearing after hemithyroidectomy for thyroid malignancy are moderately progressive, OM may be acceptable as a management option for PTMCs appearing in the remnant thyroid after hemithyroidectomy.

The magnitude of increased Levothyroxine dose during pregnancy in patients on thyroid-stimulating hormone (TSH) suppression treatment after total thyroidectomy for papillary carcinoma.

The dose of L-T4 replacement for hypothyroidism often needs to be increased after pregnancy. In our institution, patients are instructed to double the dose 2 days a week after pregnancy. However, there is scarce evidence supporting the need for a dose increase after pregnancy in patients with preconception thyroid-stimulating hormone (TSH) suppression (TSH <0.3 µIU/mL). This study aimed to determine the need for a dose increase in L-T4 among women with a TSH-suppressive dose of L-T4 before pregnancy. In this retrospective observational study, between January 2008 and December 2018, we analyzed 166 pregnancies in 134 patients on TSH suppression treatment after total thyroidectomy for papillary carcinoma. Thyroid function tests were performed before and in the first trimester of pregnancy. The dose was adjusted and maintained during the first trimester of pregnancy in 76 pregnancies (group A) and 90 pregnancies (group B), respectively. The median serum TSH level was significantly lower in group A than that in group B (0.014 µIU/mL (IQR, 0.005-0.071) vs. 0.155 µIU/mL (IQR, 0.021-0.657), p < 0.001). TSH suppression could not be maintained after pregnancy in 15.8% and 38.9% of the pregnancies in groups A and B, respectively. Increasing the post-pregnancy dose by an average of 27.4% resulted in maintenance of TSH suppression after pregnancy in 84.2% of pregnancies. In conclusion, this study suggests that increasing the L-T4 dose after pregnancy may be appropriate in postoperative thyroid cancer patients whose serum TSH levels should be suppressed.

Prevalence and Treatment Outcomes of Marine-Lenhart Syndrome in Japan.

INTRODUCTION: Marine-Lenhart syndrome (MLS) is now understood to be a combination of Graves' disease and autonomously functioning thyroid nodule(s) (AFTNs). The prevalence of the syndrome and suitable treatments for those living in iodine-sufficient areas are uncertain. OBJECTIVES: We aimed to investigate the prevalence, treatment, and prognosis of MLS in Japan, an iodine-sufficient area. METHODS: This study involved patients who visited our hospital between February 2005 and August 2019. Among patients with both thyrotoxicosis and thyroid nodule(s) larger than 10 mm, MLS and isolated AFTNs were diagnosed based on serum thyroid-stimulating hormone receptor antibody levels and scintigraphy using radioiodine or technetium-99m and thyroid uptake. RESULTS: Twenty-two patients were found to have MLS, compared to 372 with isolated AFTNs and 8,343 with Graves' disease, during the period. Therefore, the rate of MLS cases was 0.26% among all patients with Graves' disease (22/8,343). Treatments and outcomes were assessed for cases of MLS (n = 18) and isolated AFTNs (n = 269). Antithyroid drugs (ATDs) were withdrawn in 27.8% of cases in the MLS group and 10.3% in the isolated AFTN group. There was no significant difference in the clinical outcome after ATD withdrawal between the 2 groups. However, the rate of hypothyroidism after radioactive iodine (RAI) administration was significantly higher in the MLS group than in the isolated AFTN group (42.9 vs. 9.0%, p = 0.005) despite similar doses of RAI. CONCLUSIONS: The prevalence of MLS among patients with Graves' disease was 0.26% in Japan. RAI therapy induces hypothyroidism more frequently than in those with AFTNs probably because RAI is taken up in the surrounding Graves' tissues.

Autoimmune thyroid disease and thyroid function test fluctuations in patients with resistance to thyroid hormone.

OBJECTIVE: Resistance to thyroid hormone beta (RTHß) is an inherited syndrome caused by mutations in the thyroid hormone receptor ß (THRB) gene. Patients with RTHß typically have elevated thyroid hormone levels with non-suppressed serum thyroid-stimulating hormone (TSH). We aimed to elucidate the clinical, laboratory, and imaging findings of RTHß patients and further to explore their association with THRB gene mutations. DESIGN AND METHODS: We retrospectively reviewed the clinical charts and compared the clinical findings of 68 RTHß patients (45 probands and 23 relatives) and 30 unaffected relatives in Kuma Hospital. RESULTS: Genetic testing revealed 35 heterozygous THRB gene mutations. Among all RTHß patients, autoimmune thyroid disease (AITD) was detected in 42.1% of men and 40.9% of women, showing that the prevalence of AITD in affected males was significantly higher than in unaffected relatives (P = 0.019). During the follow-up of 44 patients, 13 patients (29.5%; 8 (42.1%) with AITD and 5 (20%) without AITD) temporarily showed thyroid function test results inconsistent with RTHß. Two patients with the R383H mutation, which has little dominant-negative effect, temporarily showed normal thyroid hormone and TSH levels without AITD. CONCLUSIONS: The frequency of AITD in male RTHß patients was significantly higher compared to unaffected relatives. More than 20% of RTHß patients temporarily showed laboratory findings atypical of RTHß during their follow-up, and patients with AITD and specific THRB mutations were prone to display such findings. Therefore, genetic testing should be performed even for patients with fluctuations in thyroid function test results to avoid misdiagnosis and inappropriate treatment.

[Clinical Findings of Thalamic and Brainstem Glioma Including Diffuse Midline Glioma, H3K27M Mutant:A Clinical Study].

BACKGROUND: Diffuse midline glioma, H3K27M mutant is a glioma located in the thalamus, brainstem, or spine with the H3K27M mutation, which is a new entity in the 2016 revised WHO classification. The treatment of thalamic glioma(TG)and brainstem glioma(BSG), which includes diffuse midline gliomas, the H3K27M mutant is challenging, and there are no standard therapeutic strategies. It is important to determine the characteristics of these brain tumors. Here, we retrospectively reviewed 31 consecutive patients with TG and BSG who were treated at our institute between January 1994 and May 2018, including methionine-positron emission tomography(MET-PET)data. RESULTS: Fourteen patients had TG, while 17 patients had BSG. Six patients were children, and 25 were adults. Nine patients with TGs and seven with BSG were enhanced by gadolinium. Twenty-seven patients were treated with radiotherapy, and 20 patients were treated with chemotherapy. All 21 tumors that underwent surgery showed wild-type IDH. The H3K27M mutation was present in four TG and two BSG. There was no statistically significant association between methionine uptake and gadolinium contrast enhancement and tumor grade. The median overall survival period(OS)of all cases was 16.9 months, whereas those of TG and BSG were 22.8 and 10.0 months, respectively. CONCLUSION: Because TG and BSG still have poor prognoses, it is necessary to elucidate the pathology of the disease and establish its standard therapy.

Evaluation of the diagnostic utility of the aminotransferase/lactate dehydrogenase ratio for the suspension of tissue specimens during thyroid surgery for the identification of parathyroid tissue.

Identification of the parathyroid glands during surgery is crucial for preventing postoperative hypoparathyroidism. Kikumori et al. reported that the aspartate aminotransferase (AST)/lactate dehydrogenase (LDH) ratio for the saline suspension of a suspicious tissue can differentiate parathyroid tissue from other tissues. The aim of this study was to evaluate the utility of this method and investigate the appropriate time for measurement. We obtained 465 tissue specimens during thyroidectomy of 102 patients with papillary thyroid carcinoma (PTC), and 422 specimens (129 parathyroid, 92 PTC, and 201 other tissues) with measurable AST and LDH were analyzed. Small pieces of the tissues were immersed in saline and sent for measurement of AST and LDH. The assay was performed immediately after thyroidectomy for 245 specimens (the same-day group) and during the next morning for the remaining 177 specimens (the next-day group). The accuracy of diagnosing parathyroid tissue was significantly better in the same-day group than in the next-day group. A cut-off value of 0.18 gave the best diagnostic precision, with an area under the receiver operating characteristic curve of 0.95 and 88.7% sensitivity and specificity in the same-day group. When the cut-off value was set to 0.20, the specificity for excluding carcinomatous tissues was 100%. When measured on the day of the surgery, the AST/LDH ratio for the saline suspension of the surgical specimens is useful for discriminating parathyroid tissues from other tissues. This method can be utilized at most hospitals where intraoperative frozen sections or rapid parathyroid hormone assays are not available.

Favorable outcomes of papillary thyroid microcarcinoma concurrent with Graves' disease after radioactive iodine therapy.

Graves' disease (GD) may coexist with papillary thyroid microcarcinoma (PTMC). The main purpose of this study was to evaluate whether treatment with radioactive iodine (RAI) may cause acute exacerbation of PTMC concurrent with GD or not. From the medical records of 10,257 GD patients who underwent RAI therapy between 2000-2017, 12 subjects with concurrent PTMC were retrieved. Further, 49 patients with concurrent GD and PTMC who underwent no RAI administration throughout their clinical course were enrolled as controls. Size of the PTMC nodules was evaluated based on maximal diameter and tumor volume-doubling rate (TV-DR). Among the 12 subjects who underwent RAI therapy (median dose, 13 mCi), 2 showed tumors >10 mm in maximal diameter with slow growth for more than 10 years, while the other 10 showed tumors with maximal diameter ≤10 mm. No subject showed any clinical findings of nodal or distant metastasis during the follow-up periods (0.4-11.5 years) before surgery or during active surveillance. No significant differences were observed in the TV-DR values (median, 0.044/year; range, -0.81-1.40) between the study subjects and controls (median, 0.025/year; range, -0.70-1.29; p = 0.69). When comparing the TV-DR before and after RAI administration in 3 individuals in particular, in whom PTMC were cytologically confirmed before RAI administration and whose prospective follow-up data were available, tumor progression was observed to be stable or decreased after RAI administration. There were no acute exacerbations or unfavorable outcomes of concurrent PTMC and GD after low-dose RAI administration.

Sorafenib and Lenvatinib Treatment for Metastasis/Recurrence of Radioactive Iodine-refractory Differentiated Thyroid Carcinoma.

BACKGROUND/AIM: Radioactive iodine-refractory differentiated thyroid carcinoma (RR-DTC) has been treated with multi-kinase inhibitors (MKIs), e.g., sorafenib (SOR) and lenvatinib (LEN). We analyzed the outcomes of RR-DTC patients who underwent SOR or LEN treatment at Kuma Hospital. PATIENTS AND METHODS: We enrolled 21 and 18 patients treated with SOR and LEN, respectively. RESULTS: The incidence of partial response in the LEN group was significantly higher than that in the SOR group. Serum thyroglobulin significantly decreased from the beginning of treatment to 1 month later in the LEN group (not in the SOR group). The neutrophil-lymphocyte ratio (NLR) was significantly decreased at 1 month later in both groups. An NLR ≥3 at the start of MKI treatment had a prognostic impact. CONCLUSION: For RR-DTC, LEN could be more effective than SOR, at least in the short term. The first-line drug should be selected based on other factors (e.g., adverse events, patient background).

Marked Decrease Over Time in Conversion Surgery After Active Surveillance of Low-Risk Papillary Thyroid Microcarcinoma.

Background: Active surveillance for low-risk papillary microcarcinoma (PMC) of the thyroid is an accepted and safe management strategy. However, some patients undergo conversion surgery after the initiation of active surveillance for various reasons. We investigated the reasons for conversion surgery and whether and how they changed over time. Methods: We enrolled 2288 patients with PMC who underwent active surveillance. Of these, 162 (7.1%) underwent conversion surgery >12 months after initiating active surveillance due to disease progression (57 patients), patient preference (43 patients), physician preference (31 patients), other associated thyroid or parathyroid diseases (24 patients), and other reasons (7 patients). We analyzed cumulative conversion rates not only in the whole cohort but also in the first three major subsets based on the reasons for surgery. We also divided our whole cohort into two groups based on the period of active surveillance commencement: the first-half group (February 2005-November 2011; 561 patients) and the second-half group (December 2011-June 2017; 1727 patients). Results: The criteria for PMC progression did not differ between the first- and second-half groups. The proportion of female patients in the physician preference group was significantly higher than that in the disease progression and the patient preference groups. Tumor size at surgery was larger, and tumor volume-doubling rate was higher in the disease progression group than in the other two groups. Patients in the second-half group were significantly less likely to undergo conversion surgery than those in the first-half group. Furthermore, conversion surgery rates in the second-half group were significantly lower than those in the first-half group in the patient preference, physician preference, and disease progression groups. Conclusions: Patients with PMC in the second-half group were significantly less likely to undergo conversion surgery than those in the first-half group regardless of the reason. This is probably because data accumulation of favorable outcomes with active surveillance significantly contributed to physicians' confidence and patients' trust and understanding of this disease.

Association between serum thyroid hormone balance and thyroid volume in patients treated with levothyroxine monotherapy for hypothyroidism.

Many previous studies including ours have reported that athyreotic patients on levothyroxine (LT4) have relatively low serum free triiodothyronine (FT3) levels, whereas patients with large goitrous diseases often have high serum FT3 levels. Here we investigated Hashimoto thyroiditis (HT) patients on LT4 to study the relationship between thyroid volume (TV) and thyroid hormone status in hypothyroid patients on LT4. We retrospectively studied 408 euthyroid HT patients treated with LT4 for hypothyroidism; divided them as per TV and compared serum levels of free thyroxine (FT4) and FT3 and the FT3/FT4 ratio in each patient group with those in euthyroid matched control group. We also evaluated the association between serum FT3 level and FT3/FT4 ratio and TV among HT patients on LT4. In patients with TV <15 mL, serum FT3 levels were significantly lower than those in controls. In patients with TV 15-80 mL, serum FT3 levels were equivalent to those in controls. In patients with TV ≥80 mL, the serum FT3 levels were significantly higher than those in controls. The serum FT3 level (r = 0.35, p < 0.01) and FT3/FT4 ratio (r = 0.42, p < 0.01) showed a positive correlation with TV. TVs in HT patients on LT4 caused differences in serum thyroid hormone balance, as increasing volume increases the serum FT3 level and FT3/FT4 ratio. Serum thyroid hormone balance in HT patients with smaller thyroids was similar to that in athyreotic patients. Mild thyrotropin suppression with LT4 is needed to achieve normal FT3 levels in such patients.

Selective prophylactic lateral node dissection improves the ipsilateral lateral node recurrence-free survival: A retrospective single-center cohort study.

BACKGROUND: Some studies have shown that prophylactic lateral neck dissection (pLND) may be beneficial for patients with papillary thyroid carcinoma (PTC); however, none of the Western guidelines currently recommends this procedure. Since 2007, the decision to perform pLND at our institution has been made on a case-by-case basis with different risk factors in mind. In this study, we investigated the significance and indications of pLND in patients with PTC. METHODS: We identified patients at stage N0 or N1a and M0 with PTC who underwent surgery from 2007 to 2017. We compared lateral compartment recurrence-free survival (RFS) and distant RFS between patients who did and did not undergo pLND (pLND and non-pLND groups). RESULTS: pLND was performed in 494/3177 (15.5%) patients with PTC (tumor size [T] ≥2 cm, cN0 or N1a, M0). Overall, no significant difference in lateral compartment RFS was detected between the pLND and non-pLND groups. On multivariate analysis, T ≥ 3 cm and positive extrathyroidal extension were independent predictors for recurrence to the lateral compartment. In the subset analysis of T ≥ 3 cm with positive extrathyroidal extension (n = 127), the lateral compartment RFS rate of the pLND group was significantly better (p < 0.01) than that of the non-pLND group (p < 0.01). In this subset, pLND reduced recurrence to the lateral compartment by 20.7% during the 5-year follow-up. However, pLND did not improve distant RFS. CONCLUSIONS: pLND significantly improved lateral node RFS in patients having PTC ≥3 cm with significant extrathyroidal extension. For such patients, pLND at initial surgery may be considered to avoid second surgery.