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.Genetic differentiation of Anopheles sinensis (Diptera: Culicidae) based on COⅠ and ITS2 sequences
Gang WANG ; Chun-juan SHI ; Dan KONG ; Xuan ZHU ; Ji HE ; Ming-hui ZHAO ; Chong-cai WANG
Acta Parasitologica et Medica Entomologica Sinica 2026;33(2):90-95
Objective Exploring genetic differences among geographic strains of Anopheles sinensis in China. Methods Based on the mitochondrial cytochrome oxidase subunit I(COⅠ )and ribosomal the second internal transcribed spacer(ITS2), genetic distance analyses were conducted on An. sinensis samples collected nationwide. Results Genetic differentiation was observed within An. sinensis geographic strains, primarily reflected in the genetic distances of COⅠ sequences, with some distances between samples exceeding those between closely related species. However, ITS2 sequences showed relatively low levels of differentiation within geographic strains. No significant separation was observed, and gene exchange exhibited a random pattern among geographic strains. Conclusions Significant differences in genetic distance were observed among An. sinensis samples, along with evidence of interspecific continuity among sibling species. For the identification of closely related species using wild-collected Anopheles mosquitoes samples, reliance solely on commonly used barcodes such as COⅠ and ITS2 may be insufficient. Additional molecular markers, including COⅡ and D3 gene fragments, should also be considered. Caution should be exercised when using COⅠ genes to identify cryptic species, especially within Anopheles mosquitoes.
3.Advanced strategies for the management of patients with diabetic foot ulcers: a comprehensive review
Ji Min KIM ; Chong Hwa KIM ; Seon Mee KANG ; Jung Hwa JUNG ; Ki Chun KIM ; Sanghyun AHN ; Tae Sun PARK ; Ie Byung PARK
The Korean Journal of Internal Medicine 2026;41(1):47-59
Diabetic foot ulcers (DFUs) are among the most serious and common complications of diabetes mellitus. They significantly affect patients’ quality of life and impose a substantial economic burden on healthcare systems worldwide. In Korea, the prevalence of diabetes and related complications, such as DFUs, has been increasing, reflecting a broader global trend. DFUs are associated with severe complications, including infections, neuropathy, and peripheral arterial disease, often leading to amputation. In Korea, diabetic foot complications are a major cause of non-traumatic lower-extremity amputations, with high mortality rates following amputation. DFUs also significantly reduce patients’ quality of life and increase healthcare costs. The management of DFUs requires a multidisciplinary approach that integrates medical, surgical, and advanced therapeutic interventions to prevent severe outcomes, such as amputation. This comprehensive review of DFU management in patients with diabetes was developed in collaboration with the Diabetic Study Group of the Korean Diabetes Association and Korean Society for Diabetic Foot. This review examines the epidemiology, clinical significance, diagnosis, and evidence-based treatment of DFUs.
4.Prevalence of HER2-ultralow breast cancer in South Korea: a multicenter study by reassessment of HER2-zero cases
Min Chong KIM ; Eun Yoon CHO ; Hee Jin LEE ; Ji Shin LEE ; Jee Yeon KIM ; Wan Seop KIM ; Chungyeul KIM ; Sun-Young JUN ; Hye Jeong CHOI ; So Mang LEE ; Ahrong KIM ; Ji-Young KIM ; Jeong Yun SHIM ; Gyungyub GONG ; Young Kyung BAE
Journal of Pathology and Translational Medicine 2026;60(2):184-192
This study aimed to determine the prevalence of human epidermal growth factor receptor 2 (HER2)–ultralow breast cancer among cases initially classified as HER2 immunohistochemistry (IHC) 0 and assess interobserver variability in interpreting low-level HER2 expression. Methods: In this multicenter retrospective study, all invasive breast cancer cases diagnosed between January and December 2022 across 10 Korean institutions were retrieved. Institutional pathologists reexamined HER2 IHC slides originally reported as IHC 0 according to the 2018 American Society of Clinical Oncology/College of American Pathologists guidelines and reclassified them as HER2-null (0), HER2-ultralow (0+), or HER2-low (1+). Slides from 10% of HER2-null and HER2-ultralow cases were digitized for central review and independently assessed by two pathologists, with discrepancies resolved by consensus. Results: Among 8,026 cases, 2,836 cases (35.5%) were initially reported as IHC 0. Upon re-review, 1,673 (59.0%), 1,139 (40.2%), and 24 (0.8%) cases were reclassified as HER2-null, HER2-ultralow, and HER2-low, respectively. The prevalence of HER2-ultralow breast cancer varied considerably across institutions (23.7%–78.1%). Central review of 268 digitized cases showed concordance in 193 cases (72.0%). Among the 75 discordant cases, 54 tumors (72.0%) were upgraded from HER2-null to HER2-ultralow, and 18 (24.0%) tumors were upgraded from HER2-ultralow to HER2-low. Furthermore, two tumors (2.7%) were downgraded from HER2-ultralow to HER2-null. Conclusions: Approximately 40% of cases initially categorized as IHC 0 were reclassified as HER2-ultralow. The substantial inter-institutional variability observed in interpreting low-level HER2 expression highlights the need for standardized training and quality assurance to ensure accurate identification of patients eligible for HER2-targeted antibody–drug conjugates.
5.Evaluating the Accuracy and Diagnostic Reasoning of Multimodal Large Language Models in Interpreting Neuroradiology Cases From RadioGraphics
Pae Sun SUH ; Ji Su KO ; Woo Hyun SHIM ; Hwon HEO ; Chang-Yun WOO ; Hyungjun PARK ; Chong Hyun SUH
Korean Journal of Radiology 2026;27(3):214-226
Objective:
To evaluate the accuracy and reasoning capabilities of large multimodal language models compared with those of neuroradiology subspecialty-trained radiologists in neuroradiology case interpretation.
Materials and Methods:
This experimental study used custom-made 401 radiologic quizzes derived from articles published in RadioGraphics covering neuroradiology and head and neck topics (October 2020 to February 2024). We prompted the GPT-4 Turbo with Vision (GPT-4V), GPT-4 Omni, Gemini Flash, and Claude models to provide the top three differential diagnoses with a rationale and describe examination characteristics such as imaging modality, sequence, use of contrast, image plane, and body part. The temperature was adjusted to 0 and 1 (T1). Two neuroradiologists answered the same questions.The accuracies of the large language models (LLMs) and the neuroradiologists were compared using generalized estimating equations. Three neuroradiologists assessed the rationale provided by the LLMs for their differential diagnoses using four-point scales, separately for specific lesion locations and imaging findings, and evaluated the presence of hallucinations and the overall acceptability of the responses.
Results:
Top-3 accuracy (i.e., correct answers present among top-3 differential diagnoses) of LLMs ranged from 29.9% (120 of 401) to 49.4% (198 of 401, obtained with GPT-4V in the T1 setting), while radiologists achieved 80.3% (322 of 401) and 68.3% (274 of 401), respectively (P < 0.001). Regarding the rationale for differential diagnoses, GPT-4V (T1) accurately identified both the specific lesion location and imaging findings in 30.7% (123 of 401) and 12.9% (16 of 124) of cases without textual clinical history. Hallucinations occurred in 4.5% (18 of 401), and only 29.4% (118 of 401) of the LLM-generated analyses were deemed acceptable. GPT-4V (T1) demonstrated high accuracy in identifying the imaging modality (97.4% [800 of 821]) and scanned body parts (92.2% [756 of 820]).
Conclusion
LLMs remarkably underperformed compared with neuroradiologists and showed unsatisfactory reasoning for their differential diagnoses, with performance declining further in cases without textual input of clinical history. These findings highlight the limitations of current multimodal LLMs in neuroradiological interpretation and their reliance on text input.
7.The Profile of Gut Microbiota in Carcinogenesis Driven by Mutant EGFR in Non–Small Cell Lung Cancer
Da-Som KIM ; Eun Hye KIM ; Ji Yong KIM ; Dong Ha KIM ; Yun Jung CHOI ; Jaeyi JEONG ; Young Hoon SUNG ; Dong-Cheol WOO ; Chong Jai KIM ; Jae Cheol LEE ; Miyong YUN ; Jin-Yong JEONG ; Jin Kyung RHO
Cancer Research and Treatment 2026;58(1):115-127
Purpose:
Accumulating evidence has clarified that gut dysbiosis is involved in lung cancer development and progression. Although the relationship between tumors and gut microbiota has been extensively studied using clinical samples, no studies have examined the association between mutant epidermal growth factor receptor (EGFR)–induced lung carcinogenesis and dysbiosis in gut microbiota. Therefore, we investigated the gut microbiota profiles in stool samples from human lung-specific conditional EGFR-mutant transgenic mice during lung tumor carcinogenesis.
Materials and Methods:
Stool samples were collected before tamoxifen treatment (V1) and at each time point following mutant EGFR expression in lung tissue (V2) and lung tumor appearance (V3). Fecal 16S rRNA taxonomy was analyzed to assess microbial diversity, composition, and dynamic changes at each time point.
Results:
We found that microbiota richness and diversity were significantly elevated when tumors developed and grew in the lung. Phylogenetic analysis of the microbial community revealed that Lachnospiraceae, Ruminococcaceae, Porphyromonadaceae, Rhodospirillaceae, Odoribacteraceae, and Desulfovibrionaceae showed a significant increase at the V3 stage compared to the V1 stage at the family level. In contrast, Lactobacillaceae, Bacteroidaceae, Muribaculaceae, Coriobacteriaceae, and Rikenellaceae significantly decreased at the V3 stage compared to the V1 stage. Furthermore, Lactobacillus species, also known as short chain fatty acid-producing bacteria, were relatively abundant at the V1 stage but were depleted with the occurrence of lung tumors at the V3 stage.
Conclusion
Changes in gut microbiota, such as Lactobacillus species, may be a predictive factor for the emergence and progression of tumors in an animal model of lung adenocarcinoma induced by mutant EGFR.
8.The epidemiologic characteristics of dog-bite injury during COVID-19 pandemic in Korea
Ji Heon KIM ; Youdong SOHN ; Gyu Chong CHO ; Youngsuk CHO
Journal of the Korean Society of Emergency Medicine 2025;36(2):63-71
Objective:
The frequency and severity of dog bite injuries were reported to increase during the coronavirus disease-19 (COVID-19) pandemic. This study examined the status of dog bite injuries in Korea and the changes during the COVID-19 pandemic.
Methods:
Patient information was obtained from in-depth research data on patients from January 1, 2019, to December 31, 2020, conducted by the Korea Centers for Disease Control and Prevention. The general characteristics, the situation and location at the time of the dog bite injury, severity, and the means of transport to the emergency department (ED) were evaluated, and the excess mortality ratio-adjusted injury severity score was determined to evaluate the severity. The differences between the pre-COVID pandemic (2019) and post-COVID pandemic (2020) were compared, and subgroups by age were also analyzed.
Results:
Under the COVID-19 pandemic, the number of patients decreased in all age groups. In contrast, the severity, especially in the under-19-year-old group, showed a slight but significant increase. In addition, dog bite injuries occurred most frequently in the home, particularly during the COVID-19 pandemic.
Conclusion
The severity of dog bites in those under the age of 19 was highest, which should be considered when setting more appropriate guidelines for the classification and treatment of dog-bite patients in an ED. Dog bite injuries occur most frequently during daily activity in the house. This tendency was further strengthened in the context of the COVID-19 pandemic.
9.The epidemiologic characteristics of dog-bite injury during COVID-19 pandemic in Korea
Ji Heon KIM ; Youdong SOHN ; Gyu Chong CHO ; Youngsuk CHO
Journal of the Korean Society of Emergency Medicine 2025;36(2):63-71
Objective:
The frequency and severity of dog bite injuries were reported to increase during the coronavirus disease-19 (COVID-19) pandemic. This study examined the status of dog bite injuries in Korea and the changes during the COVID-19 pandemic.
Methods:
Patient information was obtained from in-depth research data on patients from January 1, 2019, to December 31, 2020, conducted by the Korea Centers for Disease Control and Prevention. The general characteristics, the situation and location at the time of the dog bite injury, severity, and the means of transport to the emergency department (ED) were evaluated, and the excess mortality ratio-adjusted injury severity score was determined to evaluate the severity. The differences between the pre-COVID pandemic (2019) and post-COVID pandemic (2020) were compared, and subgroups by age were also analyzed.
Results:
Under the COVID-19 pandemic, the number of patients decreased in all age groups. In contrast, the severity, especially in the under-19-year-old group, showed a slight but significant increase. In addition, dog bite injuries occurred most frequently in the home, particularly during the COVID-19 pandemic.
Conclusion
The severity of dog bites in those under the age of 19 was highest, which should be considered when setting more appropriate guidelines for the classification and treatment of dog-bite patients in an ED. Dog bite injuries occur most frequently during daily activity in the house. This tendency was further strengthened in the context of the COVID-19 pandemic.
10.Management of a Large Nosocomial Outbreak From an Index of Crusted Scabies in a Tertiary Care Hospital, 2023: A Retrospective Observational Study
Jiwon JUNG ; Sun-Kyung KIM ; Eun Ok KIM ; Eun Ji CHOI ; Jihun CHOI ; Zhongfan CHANG ; Sung Eun CHANG ; Chong Hyun WON ; Sung-Han KIM
Journal of Korean Medical Science 2025;40(3):e7-
Background:
In 2023, we experienced an outbreak from a case of undiagnosed crusted scabies, resulting in a significant number of exposed individuals and secondary cases. In this report, we describe the outbreak control measures, the attack rate, and the risk factors for acquisition of scabies among healthcare workers (HCWs).
Methods:
This study was conducted in a 2,700-bed tertiary care hospital in Seoul, South Korea. The attack rate was defined both for microscopic proven cases per exposed individuals and as the sum of proven and probable cases per exposed individuals. Outbreak control measures included identifying and treating all potentially exposed individuals with or without symptoms, as well as environmental disinfection.
Results:
From the index, there was potential quinary transmission resulting in 63 proven cases, 142 probable cases, and a total of 1,820 exposed individuals, including 734 contacts from the index case. The attack rate from the index was 7% (50/734) based on proven cases and 19% (138/734) based on proven and probable cases. Among the 526 HCWs who received preemptive topical treatment with permethrin applied once, 21 (4%) were later diagnosed as scabies. In addition, 5 of 20 HCWs (25%) with initial proven scabies had a persistent positive microscopic exam after four permethrin treatments. In the case group, there were significantly more nurses (60% vs. 43%, P = 0.007) and nurse assistants (20% vs. 9%, P = 0.006). There were significantly more cases than controls involving direct contact with the index case (94% vs. 64%, P < 0.001).
Conclusion
Lowering the threshold for suspicion of crusted scabies is important, as a single missed case could lead to a large outbreak. Simultaneously applying preemptive permethrin cream to all potentially exposed individuals might have been effective in preventing further transmission. However, caution is needed because the development of scabies or persistent scabies is possible even with preemptive or therapeutic treatment.


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