1.Korean Thyroid Association Guidelines on the Management of Differentiated Thyroid Cancers; Part II. Follow-up Surveillance after Initial Treatment 2026
Eun Kyung LEE ; Seung Heon KANG ; Bon Seok KOO ; Mijin KIM ; Min Joo KIM ; Bo Hyun KIM ; Ji Won KIM ; Dong Gyu NA ; Sohyun PARK ; Ji-In BANG ; Kyorim BACK ; Youngduk SEO ; Young-Ik SON ; Young Shin SONG ; Dong Yeob SHIN ; Jong-Hyuk AHN ; Hwa Young AHN ; So Won OH ; Ho-Ryun WON ; Won Sang YOO ; Min Kyoung LEE ; Sang-Woo LEE ; Jeongmin LEE ; Ji Ye LEE ; Dong-Jun LIM ; Ki-Wook CHUNG ; Ari CHONG ; Jin Hyang JUNG ; Sun Wook CHO ; Yoon Young CHO ; Chae Moon HONG ; Young Joo PARK ;
International Journal of Thyroidology 2026;19(1):1-40
In patients with differentiated thyroid cancer (DTC), initial recurrence risk stratification based on clinical, histopathological, and perioperative data remains the key determinant for guiding management strategies during the first 1-2 years post-treatment. However, the adoption of ongoing risk stratification (ORS), which dynamically reassesses risk by integrating longitudinal clinical data and treatment response, enables more precise long-term prognostic assessment and facilitates highly individualized management. Building upon recent guidelines, the 2026 KTA guideline has been further refined by incorporating robust evidence from large-scale national cohorts and comprehensive systematic reviews. These updated recommendations outline contemporary concepts of ORS, risk-adapted TSH suppression targets, optimized surveillance modalities for recurrence detection, and disease-specific long-term follow-up strategies. Reflecting the paradigm shift toward de-escalated treatment, this revision integrates evolved perspectives on TSH suppression intensity, the clinical interpretation of thyroglobulin levels, and tailored follow-up intervals. These evidence-based recommendations aim to minimize unnecessary treatment and excessive surveillance in the large proportion of patients with excellent prognosis after initial therapy, while ensuring that each patient receives appropriately tailored and effective long-term management.
2.Evolution of Follow-up Strategies in Differentiated Thyroid Cancer: a Comparative Review of the 2015 ATA, 2024 KTA, and 2025ATA Guidelines
International Journal of Thyroidology 2026;19(1):41-47
Recent updates in international guidelines have introduced important changes in the follow-up management of differentiated thyroid cancer (DTC). This review compares the 2015 American Thyroid Association (ATA), 2024 Korean Thyroid Association (KTA), and 2025 ATA guidelines across key domains, including initial risk stratification, TSH suppression, dynamic risk stratification, and long-term surveillance. The 2024 KTA and 2025 ATA guidelines show similar trends toward more individualized and risk-adapted follow-up strategies, incorporating cumulative risk assessment and dynamic response to therapy in place of fixed, factor-based criteria. Both guidelines adopt risk-adapted TSH targets with a shift toward less intensive suppression; however, the 2025 ATA guidelines substantially simplify the TSH target framework. Differences are also observed in the interpretation of serum thyroglobulin, particularly in patients managed without radioactive iodine or after lobectomy. In long-term surveillance, both guidelines recognize that patients with a sustained excellent response have a very low risk of late recurrence, and the 2025 ATA guidelines further incorporate considerations for reducing follow-up intensity in selected patients. Overall, these guidelines support adjustment of management according to ongoing risk and clinical context, while differing in how these principles are implemented in clinical practice.
3.When Fire Meets Ice: a Case of Silent Clinical Course after Massive Levothyroxine and Sedative Co-Ingestion
Kyung-Hun SUNG ; Jaekyung LEE ; Seung-Hwan LEE ; Dong-Jun LIM
International Journal of Thyroidology 2026;19(1):110-113
Levothyroxine overdose is uncommon in adults and often presents with variable clinical severity, ranging from overt thyrotoxicosis to an entirely asymptomatic course. We report the case of a 47-year-old woman with a history of total thyroidectomy who intentionally ingested 10 mg of levothyroxine along with supratherapeutic doses of zolpidem and clonazepam at once in a suicide attempt. She presented three days later without adrenergic or gastrointestinal symptoms. Laboratory tests revealed markedly elevated free thyroxine and total triiodothyronine with suppressed thyroid stimulating hormone. She was treated with propranolol for heart rate control and empirical hydrocortisone in case of adrenal insufficiency. She remained asymptomatic with gradual biochemical improvement and normalization of thyroid function on follow-up. The protective effect of co-ingested supratherapeutic doses of gamma-aminobutyric acid (GABA)-ergic agents suggests a potential role for anti-anxiety medications in mitigating severe adrenergic symptoms in endogenous thyrotoxicosis, such as Graves’ disease.
4.Favorable Response to Radioactive Iodine Therapy in Papillary Thyroid Carcinoma with Malignant Pleural Effusion
Meihua JIN ; Cha A KIM ; Won Gu KIM
International Journal of Thyroidology 2026;19(1):104-109
Malignant pleural effusion (MPE) is a rare but severe complication of differentiated thyroid carcinoma (DTC). MPE typically occurs in advanced disease and is often refractory to radioiodine (RAI) therapy, resulting in poor survival outcomes. We report a rare case of a 52-year-old male with MPE present at the time of DTC diagnosis who demonstrated a favorable response to RAI therapy. The patient underwent three cycles of high-dose RAI (200 mCi each), resulting in sustained disease control. Despite the typical refractoriness of MPE in DTC, this case illustrates that when RAI avidity is preserved, combined treatment with RAI and supportive interventions such as thoracentesis and pleurodesis can lead to improved outcomes. This case highlights the importance of individualized treatment strategies and suggests that even advanced cases with MPE may benefit from aggressive RAI-based therapy when appropriately selected.
5.The Prevalence of BRAF Mutation in Papillary Thyroid Carcinoma Decreases Significantly with Increasing Tumor Size
Da Eun LEEM ; Hyunju PARK ; Ji Hyun YOO ; Bo Ram KIM ; Young Lyun OH ; Tae Hyuk KIM ; Sun Wook KIM ; Jae Hoon CHUNG
International Journal of Thyroidology 2026;19(1):95-103
Background and Objectives:
Studies investigating the correlation between papillary thyroid carcinoma (PTC) tumor size and the prevalence of the B-type Raf kinase (BRAF) mutation have yielded conflicting results. Therefore, we evaluated the prevalence of BRAF mutation according to tumor size in a large cohort of PTC patients to clarify this association.
Materials and Methods:
We retrospectively analyzed 6,438 patients with surgically diagnosed classic PTC between January 2009 and December 2017 at Samsung Medical Center, Seoul, Republic of Korea.During the study period, BRAF mutation testing was attempted on all fine-needle aspiration specimens, except for a small number of inadequate specimens. All other histologic subtypes were excluded. The prevalence of BRAF mutation was assessed based on tumor size, and further analyzed by age group and sex according to tumor size.
Results:
The overall prevalence of BRAF mutation was 79.2%. When PTCs ≤1 cm were excluded, the prevalence was 77.2%. The prevalence significantly decreased with increasing tumor size (p for trend <0.001). It was significantly higher in men than in women (p=0.013), but did not differ by age. The inverse correlation between tumor size and prevalence was prominent in patients aged 20-49 years but was less distinct in those aged 50 years and older.
Conclusion
In this large cohort of patients with PTC, the prevalence of BRAF mutation significantly decreased with increasing tumor size. These findings suggest that BRAF mutation is enriched in smaller surgically treated classic PTCs and may provide a hypothesis-generating clue regarding its role in early PTC development, although selection bias cannot be excluded.
6.Risk Factors and Clinical Characteristics of Graves’ Ophthalmopathy: a Retrospective Multicenter Study in Korea
Yoon Young CHO ; Hyunju PARK ; Jung HEO ; Jiyeon AHN ; Min Kyung LEE ; Jae Hyuk LEE ; Ju-Yuen LEE ; Yun Jin KIM ; Seo Young SOHN
International Journal of Thyroidology 2026;19(1):85-94
Background and Objectives:
Graves’ ophthalmopathy (GO) is an autoimmune inflammatory disorder that can adversely affect quality of life in patients with Graves’ disease (GD). The objective of this study was to characterize the clinical features of patients with GO and to identify risk factors associated with its development and the need for anti-inflammatory treatment.
Materials and Methods:
In this multicenter, retrospective observational study, 818 patients with GD were identified via electronic medical record review. Clinical characteristics were assessed, and logistic regression analyses were performed to identify risk factors for GO development and the need for anti-inflammatory treatment.
Results:
Among the 818 patients with GD, 135 (16.5%) developed GO, and 60 (7.3%) of these patients received anti-inflammatory treatment. GO was diagnosed at the time of GD diagnosis in 54.8% of cases, and proptosis and eyelid/orbital swelling were the common presenting features. In multivariable analysis, female sex (odds ratio [OR]: 1.75, confidence interval [CI]: 1.02-3.03), goiter (OR: 1.71, CI: 1.08-2.71), and smoking (ex-smokers: OR, 2.18; 95% CI: 1.02-4.65; current smokers: OR, 3.11; CI, 1.78-5.44) were independently associated with GO development, whereas diabetes (OR: 0.35, CI: 0.14-0.89) was inversely associated. Higher total cholesterol (OR: 1.31, CI: 1.01-1.04) and elevated thyrotropin-binding inhibitory immunoglobulin levels (OR: 1.07, CI: 1.02-1.11) were also significantly associated with the need for anti-inflammatory treatment.
Conclusion
This study delineated the clinical features of GO and identified risk factors for its development and the need for anti-inflammatory treatment in patients with GD, providing valuable information for the management of GO in Korean patients.
7.Impact of Poloxamer/Alginate (Guardix-SGⓇ ) Volume on Drainage after Thyroid Lobectomy
Seok-Kyung KANG ; Miri RYU ; Meehyun LEE ; Hye Won KIM ; Han Pyo HONG ; Seungju LEE
International Journal of Thyroidology 2026;19(1):78-84
Background and Objectives:
Anti-adhesion agents based on hyaluronate-carboxymethyl cellulose (HA-CMC) are widely used in thyroid surgery to reduce postoperative adhesions. However, concerns persist that higher application volumes may increase postoperative drainage and prolong hospitalization. This study aimed to evaluate the impact of different doses of an HA-CMC solution (Guardix-SGⓇ ) on postoperative drainage and clinical outcomes after hemithyroidectomy.
Materials and Methods:
This prospective study included 107 patients who underwent hemithyroidectomy with central neck lymph node dissection for thyroid cancer between January and October 2024. Patients were randomly assigned to receive either 3 g (n=57) or 6 g (n=50) of Guardix-SGⓇ intraoperatively.Postoperative drainage volume, drain duration, and length of hospital stay were compared between groups.Analysis of covariance and quantile regression were performed to assess the effects of HA-CMC dose and clinical covariates on drainage outcomes.
Results:
Baseline demographic and pathological characteristics were comparable between the two groups. Total postoperative drainage volume did not differ significantly between the 3 g and 6 g groups, even after adjustment for hospital stay (p=0.283), nor did drain duration. Quantile regression analysis revealed that hypertension was independently associated with increased drainage volume in higher quantiles (0.25– 0.75), whereas the dose of HA-CMC solution had no significant effect across any quantile.
Conclusion
Application of a higher dose (6 g) of HA-CMC solution did not increase postoperative drainage or prolong drain duration after hemithyroidectomy. These findings support the safe and effective use of higher-dose Guardix-SGⓇ in thyroid surgery.
8.Influence of Incidental Pulmonary Nodules on Surgical Decision-Making in Thyroid Cancer: a Nationwide Survey
Ja Kyung LEE ; Sukmin YUN ; Eunji KIM ; Yoon KONG ; Hyeong Won YU ; Min Joo KIM ; Jae Hoon MOON ; June Young CHOI
International Journal of Thyroidology 2026;19(1):68-77
Background and Objectives:
The clinical significance of incidental pulmonary nodules detected during thyroid cancer evaluation remains unclear. This study aimed to investigate how such findings affect surgical decisionmaking and whether management differs by physician characteristics.
Materials and Methods:
A web-based survey was distributed to 722 active members of the Korean Thyroid Association in March 2025. Eligible participants included board-certified endocrinologists, endocrine surgeons, and otolaryngologists actively treating thyroid cancer. The questionnaire included clinical scenarios featuring incidental lung nodules found during thyroid cancer work-up, with respondents asked to choose preferred surgical extent (thyroid lobectomy vs. total thyroidectomy) and management approaches.
Results:
Out of 72 physicians who completed the survey, half (n=36, 50.0%) of the respondents answered that the presence of incidental lung nodules could influence their decision on thyroidectomy extent. Among those influenced by lung nodules, 86.1% recommended total thyroidectomy in patients with high- or intermediate-risk thyroid cancer, while 11.1% would do so for all thyroid cancer patients.Endocrinologists, compared to surgeons, were more likely to choose total thyroidectomy in patients with preoperative incidental lung nodules (78.3% vs. 36.7%, p=0.001).
Conclusion
Incidental lung nodules may influence surgical planning in clinicians due to the risk of micrometastasis from thyroid cancer. Endocrinologists tend to favor a more extensive surgical approach compared to surgeons, reflecting greater concern for potential metastatic disease. These findings underscore the need for multidisciplinary consensus guidelines for the management of incidental pulmonary nodules in thyroid cancer patients.
9.The Starting Dosage of Levothyroxine for Hypothyroidism during Pregnancy
Hyunju PARK ; Arim CHOI ; Kyung-Soo KIM ; Soo-Kyung KIM ; Yong-Wook CHO
International Journal of Thyroidology 2026;19(1):60-67
Background:
and Objective: Maternal hypothyroidism increases the risk of adverse pregnancy outcomes, making appropriate levothyroxine (LT4) replacement essential. However, the optimal initial LT4 dose for women newly diagnosed with subclinical hypothyroidism (SCH) or overt hypothyroidism (OH) during pregnancy remains unclear.This study evaluated the appropriate starting LT4 dose based on baseline thyroid-stimulating hormone (TSH) and body mass index (BMI).
Materials and Methods:
This single-center retrospective cohort study included 126 pregnant women from June 2018 to April 2025. After pregnancy was confirmed, all participants started LT4.Patients were categorized by baseline TSH (2.5-4, 4-10, and >10 mIU/L) and BMI (<23, 23-<25, and ≥25 kg/m2 ) to determine the appropriate LT4 dose. The treatment goal was a TSH level <2.5 mIU/L.
Results:
Among the 126 patients, 101 (80.2%) were diagnosed with SCH or OH in the first trimester. The mean baseline TSH was 5.19 mIU/L, and 29.4% had autoimmune thyroiditis. Baseline TSH (r=0.315, p<0.001) was positively associated with weight-based LT4 dose, whereas body weight (r=−0.304, p<0.001) and BMI (r=−0.248, p=0.005) were inversely associated. The median weight-based LT4 dose was 0.45 μg/kg/day for TSH 2.5-4.0 mIU/L, 0.71 μg/kg/day for TSH 4.0-10 mIU/L, and 1.34 μg/kg/day for TSH >10 mIU/L (p for trend <0.001). Patients with TSH >10 mIU/L required more time to achieve TSH <2.5 mIU/L, and those with BMI ≥25 kg/m2 received lower weight-based LT4 doses.
Conclusion
Initial LT4 dosing should be tailored based on baseline TSH and BMI.
10.Variations in the Epidemiology of Congenital Hypothyroidism in the Asian Population: a Review
Davindu Anushka LIYANAPATHIRANAGE ; Imalke KANKANANARACHCHI ; Eric De ZOYSA ; Manjula HETTIARACHCHI
International Journal of Thyroidology 2026;19(1):52-59
Congenital hypothyroidism (CH) is an endocrine disorder but with early diagnosis and management can prevent the permanent neurodevelopment impairment. Studying the epidemiology of CH in Asian populations is essential for several reasons; To identify regional risk factors that contribute to the variation in incidence and etiology, improve and tailor newborn screening (NBS) strategies based on local demographics, environmental exposures, and healthcare resources, to guide public health supplementation and maternal thyroid health monitoring and to reduce health disparities and optimize long-term neurodevelopmental outcomes for affected children. The literature search was conducted using PubMed, Google Scholar, and the Open Access Journals for studies published between 2000 and 2025. Population-based NBS studies, national registry data, and large multicenter reports from Asian countries were included. Case reports, small case series, and studies lacking denominators were excluded. Data were extracted on incidence, screening strategies, risk factors, and etiological patterns, and narratively synthesized due to methodological heterogeneity. Higher incidence rates of CH were observed in Iran, India, Sri Lanka, and parts of the Middle East, whereas lower rates were reported in Japan, South Korea, and Central Asia. Key contributing factors included iodine imbalance, consanguinity, maternal thyroid disease, genetic susceptibility, and differences in screening protocols. Countries with universal NBS programs demonstrated earlier diagnosis and improved clinical outcomes. Expansion of universal NBS, optimization of diagnostic thresholds, and strengthening of iodine nutrition and maternal thyroid health programs are essential to reduce disease burden and improve long-term neurodevelopmental outcomes.

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