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.

The recent approval of trastuzumab deruxtecan for human epidermal growth factor receptor 2 (HER2)–low and HER2-ultralow breast cancer mandates an adequate assessment of these categories. Methods: Seven breast pathologists from the Breast Pathology Study Group of the Korean Society of Pathologists held an on-site expert consensus meeting. Fifteen sets of virtual whole slide images (WSI) of hematoxylin and eosin stain and HER2 immunohistochemistry were provided. The pathologists were given 60 minutes to submit their diagnosis of HER2 expression into null, ultralow, 1+, 2+, or 3+. Afterwards, in-depth discussion and consensus diagnoses were made by real-time visualization of the WSI. Results: After the consensus meeting, unanimous 100% agreements were seen only in five (33.3%) of the examined cases, which consisted of three 1+ cases and two 2+ cases. Two cases (13.3%) had mild disagreement, with only one pathologist’s disagreement. Of note, eight cases (53.3%) showed significant disagreement, defined by more than two pathologists’ disagreement. All HER2-null cases were reclassified as ultralow after consensus review, suggesting potential widespread underclassification of ultralow cases in clinical practice. Conclusions: Experts had significant discrepancies in interpreting HER2-low/ultralow status. It is important to assess if the distinction between HER2-low and ultralow is strictly required and if HER2-null breast cancer exists in reality.

BACKGROUND/OBJECTIVES: Dietary supplement use is common among breast cancer survivors, but studies on Asian populations remain limited. This study investigated dietary supplement use among Korean breast cancer survivors, distinguishing between vitamin/ mineral (VM) and non-vitaminon-mineral (NVNM) supplements. SUBJECTS/METHODS: This cross-sectional study included 1,136 stage I–III breast cancer survivors from 12 Korean hospitals, who survived more than 6 mon post-surgery. The participants completed a questionnaire on post-diagnostic dietary supplement use. Stepwise logistic regression was applied, calculating odds ratios (ORs) and 95% confidence intervals (CIs) to identify the demographic and clinical factors associated with VM and NVNM use. RESULTS: Seventy percent of survivors reported supplement use, with 25% using a single product. The most common VM supplements were multivitamins/minerals, vitamin D, and vitamin C, while the most common NVNM supplements included omega-3 fatty acids, probiotics, and ginseng. Survivors with higher education and greater physical activity were more likely to use VM supplements (ORs [95% CIs], 2.74 [1.76–4.25] for college graduates or above vs. middle school or below; 1.38 [1.02–1.88] for the most active group vs. the least active group). NVNM use was associated with higher education, greater physical activity levels, and a history of smoking (ORs [95% CIs], 2.29 [1.46–3.58] for college graduates or above vs. middle school or below; 1.52 [1.13–2.06] for the most active group vs. the least active group; 2.00 [1.23–3.25] for ever smokers vs. never smokers). Survivors who had undergone chemotherapy were also more likely to use NVNM supplements than those who had not (OR [95% CI], 1.37 [1.02–1.84]). CONCLUSION Seventy percent of Korean breast cancer survivors used dietary supplements in this study. VM use was associated with higher education and physical activity, while higher NVNM use was associated with higher education, greater physical activity, a history of smoking, and chemotherapy.

Purpose: The aim of this study is to compare the detection ability of quality of life (QoL) changes and responsiveness of the KOrean QUality of life in Stomach cancer patients Study group (KOQUSS)-40 and European Organization for Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ). Materials and Methods: A multicenter prospective observational study was conducted to evaluate QoL changes after various gastrectomies between January 2021 and April 2022. Participants were instructed to complete the KOQUSS-40 and EORTC QLQ-C30/STO22 preoperatively and at 1, 3, 6, and 12 months postoperatively. QoL changes over time and QoL responsiveness were assessed for each questionnaire. Results: Data from 491 patients who underwent curative gastrectomy for gastric cancer at 22 institutions were analyzed. The summary scores of the KOQUSS-40 and EORTC QLQ-STO22 showed significant differences between the total and proximal gastrectomy groups (p=0.044 and p=0.038, respectively), but no difference was observed for the EORTC QLQ-C30. Dysphagia on the KOQUSS-40 was significantly different between the total and proximal gastrectomy groups (p=0.031); however, dysphagia on the EORTC QLQ-STO22 did not differ. The responsiveness of the KOQUSS-40 was similar to that of the EORTC QLQ in patients who experienced ≥ 10% body weight loss, but approximately 10% less in patients receiving adjuvant chemotherapy than the EORTC QLQ. Conclusion KOQUSS-40 has several advantages over EORTC QLQ-C30/STO22 when comparing QoL between the total and proximal gastrectomy groups. The findings provide information for researchers investigating the QoL of patients who have undergone curative gastrectomy for gastric cancer.

Objectives: This study aimed to investigate the clinical characteristics, treatment outcomes, and factors influencing treatment success in patients with denosumab (Dmab)-related osteonecrosis of the jaw (DRONJ). Patients and Methods: This retrospective cohort study included the patients who were diagnosed with DRONJ and treated at the authors’ affiliated hospital, between August 2019 and August 2024. The patients were divided into the three groups; Group 1, low-dose Dmab; Group 2, transition from bisphosphonates (BPs) to low-dose Dmab; Group 3, high-dose Dmab. Differences in clinical characteristics among the groups were compared. Surgical outcomes were classified into three categories: complete healing, partial healing, and no healing. “Treatment success” was defined as the combined proportion of complete and partial healing. Results: A total of 178 DRONJ patients were included in this study. Most of DRONJ occurred in osteoporosis patients. In patients treated with lowdose Dmab, prior BP use resulted in the development of MRONJ within a shorter period after Dmab administration but did not affect disease severity or treatment outcomes. Overall postoperative healing outcomes were favorable at 3 months after DRONJ treatment. The overall treatment success rate was 81.5%; Group 1, 85.0%; Group 2, 82.8%; Group 3, 53.8%, P=0.027). Multiple regression analysis demonstrated that Dmab dosage was a significant factor influencing treatment success, whereas age, treatment duration, lesion location, and DRONJ stage were not (odds ratio, 5.13; 95% confidence interval, 1.19-22.14; P=0.028). Conclusion The earlier onset in the BP to Dmab transition group may be attributable to the cumulative duration of antiresorptive therapy. Patients treated with high-dose Dmab demonstrated poorer prognosis and more frequent recurrence after MRONJ treatment compared with those treated with low-dose Dmab or BP to Dmab transition therapy. herefore, these findings need to be considered for treatment of DRONJ.

Background: and Purpose: To assess the long-term effectiveness, safety, and economic viability of recently approved Alzheimer’s disease (AD) therapies, as well as to evaluate the real-world application of novel diagnostics among AD patients with diverse comorbidities, comprehensive real-world data (RWD) analysis is essential. The Korean JOint RegistrY for ALZheimer’s Treatment and Diagnostics (JOY-ALZ) endeavors to create a registry of RWD derived from clinical practice on new diagnostic methods and therapeutic agents for AD introduced in Korea since 2021. Methods: Participants must fulfill all the following: 1) be at least 19 years old; 2) be actively receiving, scheduled to initiate, or undergoing evaluation for any AD disease-modifying treatment; 3) have completed amyloid positron emission tomography or cerebrospinal fluid AD immunoassay (a positive result is not essential for participation); 4) have a clinical classification of cognitively unimpaired, mild cognitive impairment, or probable AD dementia. Data generated during routine care is segmented into a minimum dataset, extended dataset, and research-only dataset requiring extra consent. Assessments encompass clinical, cognitive, functional, neurobehavioral, neuroimaging, and biomarker evaluations, in addition to systematic monitoring of new AD treatments and their safety.Data are collected and monitored at baseline, at semiannual intervals during the initial 2 years, and then annually up to 2034. To date, 46 medical centers will participate in JOY-ALZ. Conclusions JOY-ALZ is expected to promote understanding of the long-term clinical outcomes, safety, and cost-effectiveness of recently introduced diagnostics and treatments for AD, thereby supporting the progress of precision medicine in AD care and diagnosis.

Background: Nonalcoholic fatty liver disease, a progressive condition caused by the accumulation of fat in the liver, begins with simple steatosis and can potentially progress to metabolic dysfunction-associated steatohepatitis (MASH) in the presence of inflammation and fibrosis, ultimately leading to cirrhosis or hepatocellular carcinoma. Increasing evidence indicates that sodiumglucose cotransporter 2 (SGLT2) inhibitors effectively alleviate MASH in mouse models. However, there is a lack of research on the effects of enavogliflozin on liver disease. In the present study, we investigated the effects of SGLT2 inhibitors on MASH induced by a high-fat, high-cholesterol (HFHC) diet in mice. Methods: Male C57BL/6 mice were fed a normal chow diet, HFHC diet, or HFHC diet with enavogliflozin for 12 weeks. LX-2 and HepG2 cells were treated with enavogliflozin in the presence of various pathological stimuli. Results: The HFHC diet induced excessive hepatic lipid accumulation, inflammation, and severe fibrosis. Administration of enavogliflozin not only ameliorated hepatic steatosis and fibrotic conditions but also suppressed the production of inflammatory cytokines. Positive outcomes were also observed in in vitro experiments, where enavogliflozin demonstrated the ability to impede the activation of hepatic stellate cells and alleviate lipid accumulation in hepatocytes. The potential pathway through which enavogliflozin attenuated liver fibrosis development may be associated with the transforming growth factor β1/Smad signaling pathway. Conclusion Our results suggest that enavogliflozin is effective in a mouse model of MASH by attenuating hepatic steatosis, suppressing inflammation, and improving liver fibrosis.

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.

Purpose: This study aimed to evaluate the correlation between bladder outlet obstruction (BOO) and bladder trabeculation in patients with benign prostatic hyperplasia (BPH). Methods: We analyzed data from consecutive BPH patients from July 2014 to June 2024, who underwent urodynamic study (UDS) and cystourethroscopy. The results of free uroflowmetry, filling cystometry, and pressure-flow study were analyzed to evaluate functional parameters. For anatomical parameters, bladder trabeculation grade, lateral lobe protrusion of prostate, and bladder neck elevation (BNE) measured in cystourethroscopy were used. BOO was defined as the BOO index of 40 or higher in UDS. Bladder trabeculation was graded using our previous studies. Results: Among total of 1,452 BPH patients, 1,028 patients had trabeculation on cystoscopy. Age, serum prostate-specific antigen, postvoid residual, total prostate volume, transition zone volume, terminal type detrusor overactivity, detrusor pressure at the maximal flow rate, bladder contractility index (BCI), and BOO index increased according to increase in bladder trabeculation. Multivariable logistic analysis showed that bladder trabeculation was significantly associated with age (odds ratio [OR], 1.05; P<0.001), kissing sign (OR, 1.55; P=0.007), BNE (OR, 1.76; P<0.001), detrusor overactivity (OR, 1.88; P=0.002), BCI (OR, 1.01; P=0.037), BOO (OR, 2.27; P<0.001). BOO had the greatest correlation with bladder trabeculation. In addition, BOO index showed a positive correlation (r=0.39, P<0.001) with bladder trabeculation. BOO index well distinguished between moderate trabeculation of grade 2 or higher in receiver operating characteristic analysis (area under curve=0.72, P<0.001). Conclusions Our results showed that the severity of BOO is positively associated with the severity of bladder trabeculation.

This study was conducted to identify educational needs for infection prevention and control (IPC) among staff in long-term care hospitals and to determine education priorities using the Borich model, importance-performance analysis (IPA), and the Locus for Focus (LFF) model. Methods: A descriptive crosssectional survey was conducted with 162 staff members from two long-term care hospitals in Gyeongsangbuk-do, Republic of Korea (January 5 to 16, 2026). A 32-item instrument across eight IPC domains was developed and refined based on the fourth cycle long-term care hospital accreditation standards and the national healthcareassociated infection surveillance manual. Participants rated the importance and perceived performance of each item. Data were analyzed using descriptive statistics, paired t-tests, Borich need scores, IPA, and LFF, with crosshairs based on the overall mean values. Results: Across all eight IPC domains, importance scores exceeded performance scores in both healthcare professionals and allied health personnel. At the domain level, priorities varied by occupation: overall, standard precautions and transmission-based precautions were the highest priorities. Among healthcare professionals, transmission-based precautions ranked first, followed by standard precautions, whereas among allied health personnel, standard precautions and multidrug-resistant organisms (MDRO) and antibiotic stewardship were identified as top priorities. Conclusion: IPC education in long-term care hospitals should be delivered as an integrated, role- and competency-based training system that standardizes facility-wide core practices-particularly standard precautions and transmission-based precautions-while providing job-specific advanced modules aligned with occupational scope and work processes, and should be supported by organizational measures such as monitoring, feedback, and ensuring access to IPC resources.