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.

Background: Endocrine-disrupting chemicals (EDCs) are environmental pollutants that may impair maternal and fetal health by disrupting hormonal systems, including the thyroid. Both iodine deficiency and excess are associated with thyroid dysfunction and adverse obstetrical outcomes. However, the combined impacts of EDCs and iodine exposure on maternal-fetal thyroid homeostasis remain undetermined. We established the Investigating Birth and Thyroid Outcomes of Maternal-Fetal Environmental Exposures (IBM-E) cohort to prospectively assess the effects of maternal exposures to dietary iodine and EDCs on thyroid function, pregnancy complications, and offspring growth and development. Methods: In this prospective observational study, we aim to enroll 556 pregnant women between 2024 and 2027 at a tertiary hospital in Korea. Maternal blood and urine samples will be collected at six time points, spanning from early pregnancy through 15 months postpartum, with infant samples collected at three time points. EDCs will be quantified using ultra-high performance liquid chromatography-tandem mass spectrometry. Thyroid function and urinary iodine concentration will be measured in both mothers and infants. Results: As of the current interim analyses of 193 mothers and 229 neonates, 15.0% of mothers had thyroid dysfunction and 11.4% developed preeclampsia. Preterm birth occurred in 23.8% of cases, and 16.6% of neonates were small for gestational age. Conclusion The IBM-E cohort is designed to enable the longitudinal assessment of gestational environmental exposures and their potential impacts on maternal and fetal thyroid function, as well as pregnancy and neonatal outcomes. The findings of this study may inform preventive strategies and guide policy development in perinatal environmental health.

Background/Aims: Hyperuricemia plays an essential role in the gout. Despite the clinical significance of hyperuricemia, a direct relationship between oral health and hyperuricemia has not been established. We aim to investigate the association between oral health and hyperuricemia. Methods: We selected 17,557 subjects from the Korea National Health and Nutrition Examination Survey database for the years 2016–2019. Oral health-related variables included the number of dental caries, regular tooth brushing, use of secondary oral products, and regular dental examinations. The odds ratio (OR) and 95% confidence intervals (CIs) for hyperuricemia were calculated using a multivariable-adjusted logistic regression model. Results: Oral health status with dental caries and oral health behaviors, including tooth brushing, secondary oral products, and regular dental examination, were significantly associated with hyperuricemia in all participants. The adjusted OR and 95% CIs for hyperuricemia comparing more than three dental caries with no dental caries were 1.28 (1.08–1.52). The adjusted OR and 95% CIs for hyperuricemia in regular tooth brushing, use of secondary oral products, and regular dental examination were 0.78 (0.67–0.91), 0.91 (0.83–1.00), and 0.86 (0.78–0.95), respectively. Notably, the association between oral health and hyperuricemia was more prominent in male subjects. In addition, when subjects were grouped by the oral health scoring system, the prevalence of hyperuricemia was lower in groups with better oral health scores. Conclusions We demonstrated that oral health status and behaviors are associated with hyperuricemia, particularly in males. Further studies are necessary to confirm the association between oral health and hyperuricemia.

The prevalence of thyroid cancer in pregnant women is unknown; however, given that thyroid cancer commonly develops in women, especially young women of childbearing age, new cases are often diagnosed during pregnancy. This recommendation summarizes the follow-up and treatment when thyroid cancer is diagnosed during pregnancy and when a woman with thyroid cancer becomes pregnant. If diagnosed in the first trimester, surgery should be postponed until after delivery, and the patient should be monitored with ultrasound. If follow-up before 24–26 weeks of gestation shows that thyroid cancer has progressed, surgery should be considered. If it has not progressed at 24–26 weeks of gestation or if papillary thyroid cancer is diagnosed after 20 weeks of pregnancy, surgery should be considered after delivery.

Surgical resection is typically the primary treatment for differentiated thyroid cancer (DTC), followed by radioactive iodine (RAI) and thyroid-stimulating hormone suppression therapies based on the cancer stage and risk of recurrence. Nevertheless, further treatment may be necessary for patients exhibiting persistent disease following RAI therapy, residual disease refractory to RAI, or unresectable locoregional lesions. This guideline discusses the role of external beam radiotherapy and chemotherapy following surgical resection in patients with DTC. External beam radiotherapy is ineffective if DTC has been entirely excised (Grade 2). Adjuvant external beam radiotherapy may be optionally performed in patients with incomplete surgical resection or frequently recurrent disease (Grade 2). In patients at high risk of recurrence following surgery and RAI therapy, adjuvant external beam radiotherapy may be optionally considered (Grade 3). However, external beam radiotherapy may increase the risk of serious adverse events after tyrosine kinase inhibitor therapy. Therefore, careful consideration is needed when prescribing external beam radiotherapy for patients planning to undergo tyrosine kinase inhibitor therapy. There is no evidence supporting the benefits of the routine use of adjuvant chemotherapy for DTC treatment (Grade 2).

Only a small percentage of patients (2-5%) with differentiated thyroid cancer (DTC) exhibit distant metastasis at the initial diagnosis or during the disease course. The most common metastatic sites of DTC are the lungs, followed by the bones. Radioactive iodine (RAI) therapy is considered the primary treatment for RAI-avid distant metastatic DTC. Depending on the characteristics of metastatic lesions, local treatment such as surgical resection, radiofrequency ablation, and external beam radiation therapy may be considered for some patients with metastatic DTC. Slowly growing and asymptomatic metastases can be monitored with follow-up while receiving thyroid-stimulating hormone (TSH) suppression therapy. In patients with a limited number of lung metastases and good performance status, surgical removal of the metastatic lesions may be considered. Systemic therapy should be considered for patients with progressive RAI refractory DTC. In this clinical guideline, we aim to outline the treatment principles for patients with lung, bone, and brain metastases of DTC.

The primary treatment for differentiated thyroid cancer (DTC) with distant metastasis is high-dose radioactive iodine (RAI) therapy, which can have various effects depending on the iodine uptake of thyroid cancer cells. The iodine uptake of metastatic lesions decreases over time, and approximately 40-70% of patients eventually develop RAI refractory disease. Although the prognosis of patients with RAI refractory DTC is very poor, clinical outcomes vary depending on the location and progression of metastatic lesions. Therefore, it is crucial to determine which patients should receive active systemic therapy with tyrosine kinase inhibitor (TKI) and how to apply local treatment before or during systemic therapy. This guideline covers the definition, treatment principles, systemic anticancer agents, and complications of progressive RAI-refractory DTC. RAI refractory DTC is defined as (1) the absence of RAI uptake on whole body scan, (2) presence of RAI uptake in some lesions but not in others, or (3) disease progression despite RAI uptake. Treatment options for RAI refractory DTC include surgery, external beam radiation therapy, locoregional therapies such as high-intensity focused ultrasound ablation, and systemic anticancer therapy.In patients with minimal symptoms and progression, active surveillance without specific treatment may be considered. Systemic treatment should be considered for patients with multiple progressive lesions by RECIST criteria. Furthermore, testing for cancer gene mutations, including BRAF, NTRK, and RET genes, is recommended for personalized therapy. Systemic therapy should be decided based on shared decision-making between the patient and specialist, considering anticipated benefits and risks. Regular assessment of treatment responses and evaluation of adverse events is essential, with dose adjustment based on these assessments. The optimal time of use, clinical approaches for the prevention and control of adverse events, and individualized treatment approaches based on patient characteristics will be of great help in the treatment of patients with RAI-refractory DTC.

Differentiated thyroid cancer demonstrates a wide range of clinical presentations, from very indolent cases to those with an aggressive prognosis. Therefore, diagnosing and treating each cancer appropriately based on its risk status is important. The Korean Thyroid Association (KTA) has provided and amended the clinical guidelines for thyroid cancer management since 2007. The main changes in this revised 2024 guideline include 1) individualization of surgical extent according to pathological tests and clinical findings, 2) application of active surveillance in low-risk papillary thyroid microcarcinoma, 3) indications for minimally invasive surgery, 4) adoption of World Health Organization pathological diagnostic criteria and definition of terminology in Korean, 5) update on literature evidence of recurrence risk for initial risk stratification, 6) addition of the role of molecular testing, 7) addition of definition of initial risk stratification and targeting thyroid stimulating hormone (TSH) concentrations according to ongoing risk stratification (ORS), 8) addition of treatment of perioperative hypoparathyroidism, 9) update on systemic chemotherapy, and 10) addition of treatment for pediatric patients with thyroid cancer.

The aim of this study was to develop evidence-based recommendations for determining the surgical extent in patients with locally invasive differentiated thyroid cancer (DTC). Locally invasive DTC with gross extrathyroidal extension invading surrounding anatomical structures may lead to several functional deficits and poor oncological outcomes. At present, the optimal extent of surgery in locally invasive DTC remains a matter of debate, and there are no adequate guidelines. On October 8, 2021, four experts searched the PubMed, Embase, and Cochrane Library databases; the identified papers were reviewed by 39 experts in thyroid and head and neck surgery. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was used to assess the quality of evidence, and to develop and report recommendations. The strength of a recommendation reflects the confidence of a guideline panel that the desirable effects of an intervention outweigh any undesirable effects, across all patients for whom the recommendation is applicable. After completing the draft guidelines, Delphi questionnaires were completed by members of the Korean Society of Head and Neck Surgery. Twenty-seven evidence-based recommendations were made for several factors, including the preoperative workup; surgical extent of thyroidectomy; surgery for cancer invading the strap muscles, recurrent laryngeal nerve, laryngeal framework, trachea, or esophagus; and surgery for patients with central and lateral cervical lymph node involvement. Evidence-based guidelines were devised to help clinicians make safer and more efficient clinical decisions for the optimal surgical treatment of patients with locally invasive DTC.

Background: Many studies have evaluated the prevalence of different reasons for retraction in samples of retraction notices. We aimed to perform a systematic review of such empirical studies of retraction causes. Methods: The PubMed/MEDLINE database and the Embase database were searched in June 2023. Eligible studies were those containing sufficient data on the reasons for retraction across samples of examined retracted notices. Results: A 11,181 potentially eligible items were identified, and 43 studies of retractions were included in this systematic review. Studies limited to retraction notices of a specific subspecialty or country, journal/publication type are emerging since 2015. We noticed that the reasons for retraction are becoming more specific and more diverse. In a meta-analysis of 17 studies focused on different subspecialties, misconduct was responsible for 60% (95% confidence interval [CI], 53–67%) of all retractions while error and publication issues contributed to 17% (95% CI, 12–22%) and 9% (95% CI, 6–13%), respectively. The end year of the retraction period in all included studies and the proportion of misconduct presented a weak positive association (coefficient = 1.3% per year, P = 0.002). Conclusion Misconduct seems to be the most frequently recorded reason for retraction across empirical analyses of retraction notices, but other reasons are not negligible. Greater specificity of causes and standardization is needed in retraction notices.