Objective: To investigate whether breast tissue composition on preoperative automated breast ultrasound (ABUS) is associated with the accuracy of cancer multiplicity evaluation and postoperative recurrence-free survival (RFS) in patients with early-stage breast cancer. Materials and Methods: This retrospective analysis included women with early-stage breast cancer (clinical Tis, T1–2/N0) who underwent ABUS and digital mammography (DM) between October 2019 and April 2021. Tissue composition on ABUS was assessed using the Breast Imaging Reporting and Data System background echotexture (BE) (homogeneous-fat, homogeneous-fibroglandular, or heterogeneous). In a subgroup of patients with mammographically dense breasts, the glandular tissue component (GTC) on ABUS were further stratified into high (moderate or marked) or low (minimal or mild).Multivariable logistic and Cox regression analyses were used to identify factors associated with accurate cancer multiplicity categorization (unifocal, multifocal/multicentric, or bilateral) using ABUS + DM, and with RFS, respectively. Results: Among 409 women (mean age ± standard deviation, 50.2 ± 8.7 years), ABUS combined with DM yielded accurate cancer multiplicity categorization in 368 patients (90.0%). Neither BE nor GTC on ABUS affected the accuracy of categorization when ABUS was combined with DM. Over a median postoperative follow-up of 3.5 years, 11 recurrences occurred. Heterogeneous BE on ABUS (hazard ratio [HR] 11.24 [95% confidence interval [CI]: 2.82–44.92]; P = 0.001), BRCA mutation (HR 15.94 [2.47–102.97]; P = 0.004), and pathologic index cancer size (HR per 1-cm increase 1.91 [1.13–3.23];P = 0.02) was independently associated with RFS. In patients with dense breasts, heterogeneous BE (HR 14.17 [95% CI:2.69–74.60]; P = 0.002) and high GTC (HR 10.32 [2.35–45.28]; P = 0.002) on ABUS, BRCA mutation (HR 24.34 [2.75– 215.06]; P = 0.004), and pathologic cancer size (HR per 1-cm increase 2.62 [1.50–4.59]; P = 0.001) was independently associated with RFS. Conclusion In patients with early-stage breast cancer, heterogeneous BE and high GTC on preoperative ABUS, along with larger cancer size and BRCA mutation, was associated with worse RFS. However, BE and GTC did not affect cancer multiplicity evaluation when ABUS was used in combination with DM.

Lumbar spinal stenosis (LSS) is a common degenerative spinal condition where spinal canal narrowing causes symptoms such as neurogenic claudication, radiculopathy, and lower back pain. While non-operative and surgical approaches yield similar long-term outcomes, surgical intervention—particularly decompression—can provide earlier symptom relief, functional recovery, and fall prevention in selected patients with refractory symptoms. Recent advancements in surgical technologies and image guidance have brought about a paradigm shift in LSS management. Biportal endoscopic spine surgery (BESS) has gained global traction as a minimally invasive alternative to traditional decompression methods, offering superior visualization, less soft tissue damage, shorter hospital stays, and faster recovery. High-quality studies, including randomized controlled trials, have shown promising outcomes for this technique. Furthermore, the integration of navigation systems, robot-assisted instrumentation, and artificial intelligence (AI)-driven diagnostics and surgical planning tools is transforming spinal surgery by enhancing precision in preoperative evaluation and intraoperative execution. These innovations enable accurate targeting, reduce complications, and improve reproducibility across diverse surgical settings. This review provides an updated overview of LSS, covering its pathophysiology, clinical assessment, diagnosis, and treatment. Special emphasis is placed on the growing role of BESS and the transformative impact of digital technologies such as navigation, robotics, and AI in the evolving landscape of spinal stenosis care.

Purpose: To report the clinical utility of the Barrett True-K formula in predicting multifocal intraocular lens (IOL) power in a patient with corneal deformation caused by radial keratotomy (RK), where postoperative refractive power prediction is challenging.Case summary: A 61-year-old male who underwent RK 30 years ago presented for cataract surgery. Slit-lamp examination showed eight RK incisions in each eye. Refractive error was +3.25 D sph; -1.75 D cyl, axis 70 in the right eye and +2.75 D sph; -1.00 D cyl, axis 110 in the left. Uncorrected visual acuity was 0.32 in the right eye and 0.63 in the left. IOL power was calculated using the Barrett True-K formula on the IOLMaster 700, with a target refraction of -0.25 D, and a multifocal IOL was implanted. Six months after cataract surgery, both eyes achieved a fraction close to emmetropia, with best corrected visual acuity of 0.63 in the right eye and 1.0 in the left. No significant refractive shifts or other complications were observed during surgery or 6-month follow-up. Conclusions The Barrett True-K formula, which measures the actual corneal refractive power to compensate for corneal deformation, is expected to be clinically useful for multifocal IOL implantation during cataract surgery in eyes after RK.

Purpose: Autism spectrum disorder (ASD) exhibits heterogeneous developmental trajectories; however, longitudinal studies using the Korean Childhood Autism Rating Scale (K-CARS) are scarce. This study examined diagnostic changes and related developmental characteristics through repeated K-CARS assessments. Methods: We retrospectively reviewed the medical records of children who underwent repeated K-CARS assessments between May 2021 and December 2024 at Gyeongsang National University Hospital. Based on diagnostic status at the initial (T1) and follow-up (T2) evaluations, participants were classified as having persistent ASD (ASD at T1 and T2), emerging ASD (non-ASD at T1 but ASD at T2), or desisting ASD (ASD at T1 but non-ASD at T2). Developmental profiles were evaluated using the social quotient (SQ), visual-motor integration (VMI), and language quotients. Results: Forty-three children (32 boys; median age, 2.9 years at T1 and 4.3 years at T2) were included. Twenty-two met ASD criteria at T1, and 15 (68%) retained the diagnosis at T2. Across the cohort, 15 (35%) had persistent ASD, 21 (49%) had emerging ASD, and seven (16%) had desisting ASD. The desisting group showed higher baseline VMI and better outcomes at follow-up. The emerging group initially had higher SQ and VMI than the persistent group, but these differences disappeared over time. Higher baseline VMI was associated with desisting status and higher baseline SQ with emerging ASD (odds ratios, 3.14 and 2.59 per standard deviation increase, respectively; P=0.06 and P=0.07). Conclusion Early ASD diagnoses were generally stable yet variable, supporting repeated assessment. Baseline VMI and SQ may relate to later diagnostic changes.

Purpose: Preterm birth remains a leading cause of long-term neurodevelopmental impairment, yet early evaluations frequently underestimate subsequent deficits. This study examined longitudinal neurodevelopmental trajectories across gestational age groups and identified predictors of developmental delay. Methods: A retrospective cohort of 532 preterm children, stratified by gestational age, was followed from the neonatal period to early preschool age. Neurodevelopment was assessed using the Korean version of the Bayley Scales of Infant and Toddler Development, Third Edition at 8–12 months (n=481), 13–24 months (n=118), and 25–42 months (n=100). Longitudinal trajectories were analyzed using general linear models, and predictors of developmental delay were identified through multivariable logistic regression. Results: During the first year, motor scores differed significantly across gestational age groups, with extremely preterm infants showing the lowest values. By the third to fourth years of life, cognitive and language scores diverged markedly, with extremely preterm children exhibiting the steepest decline and additional deficits in motor and adaptive behavior domains. Lower gestational age remained an independent predictor of both cognitive and language delay at early preschool age, while no independent predictors were identified for motor, social-emotional, or adaptive behavior outcomes. Conclusion Neurodevelopmental outcomes in preterm children follow dynamic, domain-specific trajectories influenced by gestational age and developmental timing. Motor delays are most evident in infancy, whereas cognitive and language impairments emerge by early preschool age. Gestational age remains a consistent predictor of later delay, emphasizing the need for longitudinal, gestational age–stratified monitoring and early, targeted intervention.

Rectal cancer, which accounts for approximately 40% of colorectal cancers, remains a major clinical concern. Recent advances in diagnostic imaging, surgical techniques, radiotherapy, and systemic treatment have steadily improved rectal cancer outcomes. Considering this, the Korean Rectal Cancer Multidisciplinary (KRCM) Committee has aimed to provide clinicians and policymakers with up-to-date, evidence-based clinical practice guidelines to support optimal decision-making, reflecting current evidence, the Korean healthcare context, and patient values and preferences. The Clinical Practice Guidelines for Rectal Cancer version 2.0 were developed through multidisciplinary collaboration with related academic societies, building upon and updating the KRCM Clinical Practice Guidelines version 1.0 (titled “Multidisciplinary guidelines for the management of rectal cancer”). These consensus guidelines of the KRCM were established based on a comprehensive literature review, evidence synthesis, with recommendation development guided by the GRADE (Grading of Recommendations Assessment, Development and Evaluation) methodology, and consideration of applicability in real-world clinical practice under the national health insurance system. Each recommendation has been presented with its strength and level of evidence.

Some viral infections display distinct seasonal patterns influenced by factors such as climate, human behavior, and viral characteristics. In this review, we investigated the seasonality of 15 viral infections in Korea. We analyzed viruses for which national surveillance data are available from the Korea Disease Control and Prevention Agency, including influenza virus, respiratory syncytial virus (RSV), rhinovirus, parainfluenza virus, metapneumovirus, human bocavirus, seasonal coronaviruses, enterovirus, adenovirus, norovirus, rotavirus, Japanese encephalitis virus, Hantaan virus, varicella–zoster virus, and mumps virus. In temperate climates, such as that in Korea, winter peaks are commonly observed for influenza, RSV, and norovirus infections, whereas enteroviruses are more prevalent in summer and early autumn. Parainfluenza viruses exhibit type-specific seasonality (circulating in warmer months from spring to autumn). During the coronavirus disease 2019 pandemic (2020– 2021), the incidence of most respiratory and gastrointestinal viral infections analyzed in this study declined substantially owing to non-pharmaceutical interventions, such as social distancing and mask-wearing. After the preventive measures were relaxed, many viruses initially exhibited delayed or atypical seasonal peaks. However, by 2024, the seasonality of most, but not all, viral infections had largely returned to their pre-pandemic patterns. We also reviewed factors influencing viral seasonality, including climatic conditions, vector activity, human behavior, immunity, and viral genetic variation. These findings highlight the dynamic nature of viral seasonality and reinforce the importance of timely surveillance and flexible public health responses tailored to each country’s epidemiological landscape.

Background: Copy number variations (CNVs) play an important role in human genetic disorders. Detection of exon-level CNVs is crucial for accurate clinical diagnosis. The CytoScan XON Array, a high-resolution microarray, was recently developed to detect exonic CNVs of various genes. Methods: We evaluated the clinical performance of the CytoScan XON Array using 59 patient samples with previously identified CNVs, confirmed via methods including multiple ligation-dependent probe amplification (MLPA), gene-dose PCR, and mRNA assay. Concordance between CytoScan XON and orthogonal methods was evaluated in target regions, and diagnostic utility was compared with that of genome sequencing (GS)-based CNV calling tools through analysis of false-positive CNVs in non-target genomic regions. Results: For target regions, the CytoScan XON Array achieved concordance rates of 89.8% and 92.5% at the exon and gene levels, respectively, for all CNV calls. Concordance was higher for multi-exon CNVs (100%) than that for single-exon CNVs (82.6%, P = 0.03). For non-target regions, false-positive CNV calls were reduced to fewer than 0.01 per gene per person through filtering strategies. The array exhibited false-positive detection rates within dosage-sensitive genes comparable with those of GS-based tools. Conclusions The CytoScan XON Array, a reliable tool for detecting exon-level CNVs in target regions, can serve as a complementary approach to GS-based CNV calling tools for genome-wide CNV screening with high resolution. However, its performance for single-exon CNVs requires further optimization. Cross-validation with GS-based CNV calling tools is recommended to improve diagnostic accuracy.

Background: Lithium hydroxide (LiOH) is increasingly used in electric vehicle battery production; however, its health effects in the work environment remain underreported. This study characterizes the acute health effects on workers following accidental occupational exposure to LiOH at a Korean lithium plant in March 2024. Methods: We analyzed health effects from two LiOH exposure accidents on March 6 and 9, 2024, involving 50–100 kg powder spills. Two datasets were examined: acute symptoms from 115 workers who visited hospitals immediately after exposure, and a symptom severity survey from 474 workers conducted 2 weeks post-exposure. Workers were stratified by distance from the leak source (<10 m, 10–20 m, >20 m) and respirator use. Univariate general linear modeling was applied to analyze the relationship between symptom occurrence and both the distance from the exposure source and respirator use. Results: Among workers visiting hospitals immediately, local irritation symptoms predominated: sore throat (58.3%), cough (28.7%), and skin dermatoses (17.4%). Systemic symptoms included headache (45.2%), nausea (18.3%), chest tightness (12.2%), and dizziness (9.6%). Two-week follow-up revealed overall symptom improvement; severe cough decreased from 22.2% to 10.1%. However, despite general improvement, a significant portion of workers reported persistent respiratory issues, including cough (28.7%) and sputum production (31.0%). Symptom severity showed a significant dose-response relationship with proximity to the source (p < 0.001). While respirator use offered initial protection (p = 0.021), this effect was not statistically significant after 2 weeks. Conclusions Occupational LiOH exposure caused acute irritation and systemic symptoms, demonstrating immediate tissue damage consistent with its alkalinity and systemic toxicity upon absorption. As lithium battery production expands globally, these results emphasize the necessity for developing specific occupational exposure limits and medical surveillance guidelines for lithium compounds.