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.

Objectives: Assessing healthcare quality at the national level is essential for evaluating health system performance and identifying areas requiring improvement. This study examined long-term trends in healthcare quality in Korea from 2008 to 2023 using internationally comparable indicators. Methods: We conducted a trend analysis of healthcare quality in Korea using the Organization for Economic Cooperation and Development (OECD) Health Care Quality and Outcomes framework and quality indicators. Indicators across multiple domains, including acute care, primary care, prescribing in primary care, mental healthcare, and patient experiences, were analyzed and compared with OECD averages. Results: Healthcare quality in Korea improved across several domains. Thirty-day mortality for acute myocardial infarction decreased from 14.2% in 2008 to 10.2% in 2023, while mortality for ischemic stroke declined from 8.7% to 5.5%. Avoidable hospitalizations decreased substantially, with hospitalizations for chronic obstructive pulmonary disease declining by 59.7%. The proportion of patients with diabetes receiving cholesterol-lowering treatment increased from 44.1% to 82.5%. However, the proportion of broad-spectrum antibiotic prescriptions remained substantially higher than the OECD average (40.3 vs. 15.5%). In mental healthcare, excess mortality ratios increased from 4.3 in 2010 to 4.9 in 2023 for schizophrenia and from 3.5 to 4.3 for bipolar disorder, while post-discharge suicide rates showed little improvement. Patient experience indicators related to patient-physician communication improved and approached OECD averages. Conclusions Healthcare quality in Korea improved substantially between 2008 and 2023, particularly in acute care outcomes and chronic disease management. However, persistent challenges remain in areas such as antibiotic use, polypharmacy, and mental healthcare. These findings provide internationally comparable evidence to inform future health policy and healthcare quality improvement efforts.

Myopia, particularly high myopia, is a significant risk factor for several ocular pathologies including cataract, glaucoma, and retinal detachment. Excessive axial elongation associated with high myopia can induce biomechanical stretching, increasing the risk of serious complications like posterior staphyloma and myopic maculopathy. Global meta-analyses estimate that approximately 10 million people were visually impaired due to myopic maculopathy in 2015, with 3 million being blind. Recent nationwide surveys in South Korea revealed a prevalence of 65.4% for myopia and 6.9% for high myopia in children and adolescents, highlighting the urgent need for effective management. Delaying the onset and slowing the progression of myopia during childhood and adolescence is crucial for reducing the potential lifetime risk of these complications. This consensus statement, prepared by the Korean Myopia Society for the Korean Association for Pediatric Ophthalmology and Strabismus (KAPOS), reviews the current evidence for myopia control interventions and provides management strategies applicable to the South Korean clinical setting. Key interventions covered include lifestyle modifications (outdoor time, near work adjustment), optical methods (myopia-control spectacle lenses, dual-focus soft contact lenses, orthokeratology), and pharmacologic treatment (low-concentration atropine), as well as combination therapies. The statement also addresses patient selection, treatment outcome evaluation using spherical equivalent and axial length changes, and the crucial aspects related to treatment cessation and the rebound effect.

Purpose: Older cancer patients face unique challenges due to age-related physiological changes, increasing their vulnerability to treatment-related toxicities. Geriatric assessment (GA) is a validated tool for optimizing care, yet there is no consensus on integrating geriatric interventions into oncology. This study evaluates the feasibility of a tailored onco-geriatric intervention model incorporating the KG-7 screening tool. Materials and Methods: This prospective study included 30 patients aged ≥ 70 years with solid tumors undergoing adjuvant or palliative chemotherapy. Patients scoring ≤ 5 of KG-7 were eligible. Tailored interventions incorporating KG-7 included polypharmacy, functional status, mobility, nutrition, cognition, emotional well-being, insomnia, social support, and medical problem. KG-7, GA, and quality of life (QoL) were followed at 12 weeks. Results: Participants (median age, 79.5 years) had colon (43.3%), pancreatic (23.3%), or gastric cancer (23.3%). At baseline, most patients showed independent activities of daily living (100%)/instrumental activities of daily living (90%). However, 93.3% had abnormal GA. Particularly, 86.7% were either malnourished or at risk of malnutrition. The most frequently identified intervention needs included polypharmacy (70.0%), nutritional support (60.0%), and emotional well-being (50.0%) with high adherence (100.0%, 88.9%, and 46.7%, respectively). At 12 weeks, KG-7 scores improved in 43.8% of patients, and 69.2% of GA domains were improved. QoL analysis revealed modest improvement in Global Health Status (mean difference, 6.3; p=0.176). One-year survival rates were 92.3% and 79.4% for adjuvant and palliative groups, respectively. Conclusion The onco-geriatric intervention model incorporating KG-7 demonstrated high feasibility and potential to enhance clinical outcomes. Future studies should validate this approach in randomized trials to optimize care for older cancer patients.

Metaverse-based mental health interventions have recently emerged as an extension of telepsychiatry, digital therapeutics (DTx), and virtual reality (VR)–based treatments for children and adolescents. The coronavirus disease 2019 pandemic accelerated the adoption of remote psychological assessment and intervention, raising critical questions regarding their clinical validity, developmental appropriateness, and long-term applicability in youth populations. Accumulating evidence has demonstrated that remote assessments and internet-based interventions can achieve clinical outcomes comparable to face-to-face approaches in selected domains, particularly anxiety, depression, and social communication difficulties. In parallel, immersive technologies such as VR and metaverse-based platforms have been applied to exposure-based interventions, social skills training, and emotion regulation in controlled and repeatable environments. This narrative review examined 48 empirical and review studies on telepsychiatry, internet-based cognitive behavioral therapy, DTx, VR, and metaverse-based interventions for children and adolescents. Neurobiological mechanisms relevant to fear extinction, executive function, emotion regulation, and social cognition were critically reviewed. In addition, real-world implementation experiences from a hospital-based Wee Center in Korea were integrated to evaluate feasibility within school-linked mental health services. The findings suggested that metaverse-based counseling should not be conceptualized as a stand-alone replacement for face-to-face treatment, but rather as a complementary, hybrid platform linking remote screening, structured digital intervention, and in-person clinical care. While current evidence supported feasibility and conditional clinical utility, further longitudinal, controlled, and cost-effectiveness studies were required to establish its role in pediatric mental health.

Background: Immune checkpoint inhibitors (ICIs) have transformed the treatment of metastatic solid tumors; however, they induce immune-related adverse events, such as ICI-induced type 1 diabetes mellitus (ICI-T1DM), a rare but serious condition requiring lifelong insulin therapy. We aimed to identify the risk factors and survival outcomes associated with ICI-T1DM to optimize screening and mitigate adverse effects. Methods: This retrospective cohort study analyzed 6,956 patients treated with ICIs at a tertiary care center between January 1, 2017, and February 28, 2023. ICI-T1DM was classified based on the need for persistent insulin therapy post-ICI and a C-peptide level <1.0 ng/mL. Patient demographics, clinical characteristics, treatment details, and survival outcomes were examined. Results: ICI-T1DM was identified in 32 patients (0.46%) with a median onset time of 41 weeks. Significant risk factors included pre-existing diabetes (hazard ratio [HR], 2.352; 95% confidence interval [CI], 1.140 to 4.854), combination therapy with anti-programmed death-1 (PD-1)/programmed death-ligand 1 (PD-L1) and anti-cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) inhibitors (HR, 3.666; 95% CI, 1.224 to 10.979), prolonged ICI treatment (≥12 weeks; HR, 4.789; 95% CI, 1.806 to 12.701), and thyroid dysfunction (HR, 4.027; 95% CI, 1.847 to 8.779). ICI-T1DM occurrence and thyroid dysfunction were associated with improved survival (HR, 0.224; 95% CI, 0.093 to 0.539; and HR, 0.616; 95% CI, 0.566 to 0.670). Conclusion Patients with pre-existing diabetes, combined anti–PD-1/PD-L1 and anti–CTLA-4 therapy, prolonged ICI treatment (≥12 weeks), and thyroid dysfunction are at high risk of developing ICI-T1DM. The observed survival benefits in patients with ICI-T1DM underscore the importance of aggressive glucose monitoring and patient education for early detection and management.

Background: and Purpose To compare the epidemiological and clinical features of the rare patients with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) with age- and sex-matched controls in a nationwide cohort from South Korea. Methods: This observational cohort study analyzed newly diagnosed CADASIL patients aged at least 20 years and matched controls using data from the National Health Information Database for 2004–2022. The cumulative incidence of CADASIL was assessed by age and sex, and compared between regions. Neurologic and systemic diseases were compared between the CADASIL and control groups. Results: The study analyzed 816 CADASIL patients and 816 age- and sex-matched controls aged 56.8±15.2 years (mean±standard deviation), among whom 48.3% were male. The cumulative incidence of CADASIL was 1.86 per 100,000 people (95% confidence interval [CI]=1.85– 1.87 per 100,000), and peaked at 60–69 years of age. In terms of regional distribution, the incidence was highest for Jeju, at 39.67 per 100,000 (95% CI 37.84–41.49 per 100,000). Neurologic diseases were more frequent in CADASIL patients, including Alzheimer’s disease (33.1% vs.20.0%), vascular dementia (84.9% vs. 5.0%), epilepsy (34.6% vs. 15.9%), stroke (70.7% vs. 27.6%), parkinsonism (18.9% vs. 11.0%), and depression (60.8% vs. 44.9%). Systemic diseases such as diabetes mellitus (78.9% vs. 68.9%) were also more common in CADASIL patients, while cancer (27.9% vs. 38.7%) and myocardial infarction (10.0% vs. 13.6%) were less common than in controls. The onset ages of all diseases were lower in CADASIL patients. Conclusions This study has provided a precise nationwide estimate of the CADASIL incidence and its regional distribution in South Korea. CADASIL patients showed higher incidence rates and earlier onsets of diverse clinical manifestations.

Background: and Purpose: Plasma biomarkers, including phosphorylated tau (ptau217), glial fibrillary acidic protein (GFAP), and neurofilament light chain (NfL), are promising tools for detecting Alzheimer’s disease (AD) pathology. However, cross-laboratory reproducibility remains a challenge, even when using identical analytical platforms such as single-molecule array (Simoa). This study aimed to compare plasma biomarker measurements (ptau217, GFAP, and NfL) between 2 laboratories, the University of Gothenburg (UGOT) and DNAlink, and evaluate their associations with amyloid positron emission tomography (PET) imaging. Methods: Plasma biomarkers were measured using Simoa platforms at both laboratories:the UGOT and DNAlink Incorporation. Diagnostic performance for predicting amyloid PET positivity, cross-laboratory agreement, and the impact of normalization techniques were assessed. Bland-Altman plots and correlation analyses were employed to evaluate agreement and variability. Results: Plasma ptau217 concentrations exhibited strong correlations with amyloid PET global centiloid values, with comparable diagnostic performance between laboratories (area under the curve=0.94 for UGOT and 0.95 for DNAlink). Cross-laboratory agreement for ptau217 was excellent (r=0.96), improving further after natural log transformation. GFAP and NfL also demonstrated moderate to strong correlations (r=0.86 for GFAP and r=0.99 for NfL), with normalization reducing variability. Conclusions Plasma biomarker measurements were consistent across laboratories using identical Simoa platforms, with strong diagnostic performance and improved agreement after normalization. These findings support the scalability of plasma biomarkers for multicenter studies and underscore their potential for standardized applications in AD research and clinical practice.

Background: Recombinant human follicle-stimulating hormone (rhFSH) is commonly used to treat female infertility, but its short half-life necessitates multiple doses. Even corifollitropin alfa, with an extended half-life, requires supplementary injections of rhFSH after 7 days. This study aimed to develop and evaluate a long-acting follicle-stimulating hormone (FSH) formulation using anti-serum albumin Fab-associated (SAFA) technology to avoid additional injections and enhance ovarian function. Methods: SAFA-FSH was synthesized using a Chinese hamster ovary expression system. Its biological efficacy was confirmed through assays measuring its ability to stimulate cyclic adenosine monophosphate (cAMP) production, estradiol synthesis, and the expression of human cytochrome P450 family 19 subfamily A member 1 (hCYP19α1) and human steroidogenic acute regulatory protein (hSTAR) in human ovarian granulosa (KGN) cells. To evaluate the effects of SAFA-FSH, we compared its impact on serum estradiol levels and ovarian weight increase with that of rhFSH in Sprague-Dawley (SD) rats using the modified Steelman-Pohley test. Results: The results indicated that SAFA-FSH induces cAMP synthesis in KGN cells and upregulates the expression of hCYP19α1 and hSTAR in a dose-dependent manner. Female SD rats, aged 21 days, receiving daily subcutaneous human chorionic gonadotropin injections for 5 days exhibited a significant increase in serum estradiol levels and ovarian weight when administered SAFA-FSH on the first day or when given nine injections of rhFSH over 5 days. Notably, the group receiving SAFA-FSH on the first and third days demonstrated an even greater rise in serum estradiol levels and ovarian weight. Conclusion These findings suggest that SAFA-FSH presents a promising alternative to current rhFSH treatments for female infertility. However, further research is essential to thoroughly assess its safety and efficacy in clinical contexts.

Background: In this comprehensive retrospective nationwide cohort study, we examined the relationships between various asthma medications and bone health, utilizing data from the National Health Insurance Service database of South Korea. Methods: From 2015 to 2019, the relevant dataset included 168,611 individuals aged 66 years, among whom 8,747 were diagnosed with asthma. We focused on a subset of 6,173 patients, all 66-year-old women. Participants were categorized into four groups: nonusers of asthma medication (n=2,868), leukotriene antagonist users (n=2,281), inhaled corticosteroid (ICS) users (n=517), and those using a combination of ICS and long-acting beta-agonist (ICS+LABA) medication (n=507). The primary outcomes measured were the incidences of major osteoporotic fractures and hip fractures during the follow-up period. Results: Over 2.7 years of follow-up, 615 cases of major osteoporotic fractures and 96 cases of hip fractures were recorded. ICS users exhibited a heightened risk of both injuries, with hazard ratios of 1.38 (95% confidence interval [CI], 1.18 to 1.63; P<0.001) for major osteoporotic fractures and 1.56 (95% CI, 1.33 to 1.83; P<0.001) for hip fractures. Similarly elevated risks were observed in the ICS+LABA group. Notably, the risk associated with ICS was particularly pronounced among patients with osteopenia for both fracture types. Overall, the use of ICS, alone or in combination with LABA, in patients with asthma is associated with significantly increased risks of osteoporotic fractures, especially among those with osteopenia. Conclusion These findings underscore the importance of considering bone health when managing asthma, especially in older patients and those with existing bone density issues.