Background: Small cell lung cancer (SCLC) is called ‘smoker’s disease’ because it is strongly associated with smoking and most cases occur in smokers. However, it can also occur in never smokers. We investigated the clinical features of never smokers with SCLC and compared their treatment outcomes with those of smokers with SCLC. Methods: We retrospectively reviewed the clinical data of patients who had proven SCLC and had received chemotherapy at a single cancer center between July 2002 and April 2021. Results: Of 1,643 patients, 1,416 (86.2%) were enrolled in this study. A total of 162 (11.4%) and 1,254 (88.6%) patients were never smokers and smokers, respectively. There were more female never smokers than smokers (n=130; 80.2% vs. 79, 6.3%, p=0.000), and the incidence of ischemic heart disease was lower among never smokers than among smokers (4/1,416, [2.5%] vs. 83/1,416 [6.6%], p=0.036). Never smokers showed less symptoms at diagnosis than smokers (80.9% vs. 87.2%, p=0.037); however, they showed more toxicity after first-line treatment (61.7% vs. 47.8%, p=0.001). The objective response rate (ORR) was significantly higher in never smokers (74.1% vs. 59.6%, p=0.000). In the multivariate analysis, never smoking and second-line treatment were associated with a better ORR. However, progression-free survival and overall survival were not significantly different between never smokers and smokers. Conclusion In conclusion, never smokers accounted for 11.4% of patients with SCLC. They had distinguishing clinical characteristics and showed better chemotherapeutic responses than smokers.

The initial molecular cytogenetic characteristics of blasts plays a significant role in determining the treatment course of B-cell acute lymphoblastic leukemia (B-ALL).B-ALL with intrachromosomal amplification of chromosome 21 (iAMP21) has been well known to have unfavorable prognosis. Also, there are previously recognized germline mutations that increase the risk of ALL, such as trisomy 21, Down syndrome. This case report is about a 16-year-old girl who presented with lymphadenitis, purpura, and fever followed by initial lab of elevated white blood cell with blasts.She had some notable facial features, but no typical Down syndrome related one.Bone marrow biopsy and fluorescence in situ hybridization finalized the diagnosis as B-ALL with iAMP21, high-risk group. The minimal residual disease-negative complete remission was achieved after the induction chemotherapy with Korean multicenter high-risk protocol. However, abnormal karyotype was sustained in bone marrow. Microarrays with her buccal swab raised the possibility that the abnormal karyotype was not from the leukemic blasts but rather from the germline. Although she underwent scheduled chemotherapy uneventfully as slow early responder type, thrombocytopenia and abnormal karyotype persisted, leading to the diagnosis of acute myeloid leukemia. Additional chemotherapy and peripheral blood stem cell transplantation was performed which resulted in engraftment. This case highlights the discovery of a constitutional genetic aberration, which played like a silent yet critical background factor for B-ALL with iAMP21. As the number of reported cases are limited, the role of germline chromosome 21 mutation as the indicator for prognosis of B-ALL should be studied further.

Background: and Purpose: This clinical practice guideline provides evidence-based recommendations for treatment of dementia, focusing on cholinesterase inhibitors and N-methyl-D-aspartate (NMDA) receptor antagonists for Alzheimer’s disease (AD) and other types of dementia. Methods: Using the Population, Intervention, Comparison, Outcomes (PICO) framework, we developed key clinical questions and conducted systematic literature reviews. A multidisciplinary panel of experts, organized by the Korean Dementia Association, evaluated randomized controlled trials and observational studies. Recommendations were graded for evidence quality and strength using Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) methodology. Results: Three main recommendations are presented: (1) For AD, cholinesterase inhibitors (donepezil, rivastigmine, galantamine) are strongly recommended for improving cognition and daily function based on moderate evidence; (2) Cholinesterase inhibitors are conditionally recommended for vascular dementia and Parkinson’s disease dementia, with a strong recommendation for Lewy body dementia; (3) For moderate to severe AD, NMDA receptor antagonist (memantine) is strongly recommended, demonstrating significant cognitive and functional improvements. Both drug classes showed favorable safety profiles with manageable side effects. Conclusions This guideline offers standardized, evidence-based pharmacologic recommendations for dementia management, with specific guidance on cholinesterase inhibitors and NMDA receptor antagonists. It aims to support clinical decision-making and improve patient outcomes in dementia care. Further updates will address emerging treatments, including amyloid-targeting therapies, to reflect advances in dementia management.

Background: This study aimed to investigate the prevalence, management, and comorbidities of diabetes mellitus among Korean adults. Methods: Data from the Korea National Health and Nutrition Examination Survey (2019–2022) were analyzed to assess the prevalence, treatment, risk factors, and comorbidities of diabetes. Comparisons between young and older adults with diabetes were emphasized. Results: Among Korean adults aged ≥30 years, the prevalence of diabetes is 15.5% during 2021–2022. Of these, 74.7% were aware of their condition, 70.9% received antidiabetic treatment, and only 32.4% achieved glycosylated hemoglobin (HbA1c) <6.5%. Moreover, 15.9% met the integrated management targets, which included HbA1c <6.5%, blood pressure <140/85 mm Hg, and low-density lipoprotein cholesterol <100 mg/dL. In young adults aged 19 to 39 years, the prevalence of diabetes was 2.2%. Among them, 43.3% were aware of their condition, 34.6% received treatment, and 29.6% achieved HbA1c <6.5%. Obesity affected 87.1%, and 26.9% had both hypertension and hypercholesterolemia. Among adults aged ≥65 years, the prevalence of diabetes was 29.3%, with awareness, treatment, and control rates of 78.8%, 75.7%, and 31.2%, respectively. Integrated management targets (HbA1c <7.5%, hypertension, and lipids) were achieved by 40.1%. Conclusion Diabetes mellitus remains highly prevalent among Korean adults, with significant gaps in integrated glycemic, blood pressure, and lipid control. Older adults with diabetes show higher awareness and treatment rates but limited integrated management outcomes. Young adults with diabetes bear a significant burden of obesity and comorbidities, alongside low awareness and treatment rates. Therefore, early intervention programs, education, and strategies tailored to younger populations are urgently required.

Background: This study aimed to examine trends in the prevalence, incidence, metabolic characteristics, and management of type 2 diabetes mellitus (T2DM) among young adults in South Korea. Methods: Young adults with T2DM were defined as individuals aged 19 to 39 years who met the diagnostic criteria for T2DM. Data from the Korean National Health Insurance Service-Customized Database (2010–2020, n=225,497–372,726) were analyzed to evaluate trends in T2DM prevalence, incidence, metabolic profiles, comorbidities, and antidiabetic drug prescription. Additional analyses were performed using the Korea National Health and Nutrition Examination Survey. Results: The prevalence of T2DM in young adults significantly increased from 1.02% in 2010 to 2.02% in 2020 (P<0.001), corresponding to 372,726 patients in 2020. Over the same period, the incidence rate remained stable within the range of 0.36% to 0.45%. Prediabetes prevalence steadily increased from 15.53% to 20.92%, affecting 3.87 million individuals in 2020. The proportion of young adults with T2DM who were obese also increased, with 67.8% having a body mass index (BMI) ≥25 kg/m² and 31.6% having a BMI ≥30 kg/m² in 2020. The prevalence of hypertension, dyslipidemia, and fatty liver disease also increased, reaching 34.2%, 79.8%, and 78.9%, respectively, in 2020. Although the overall pharmacological treatment rate remained low, the prescription of antidiabetic medications with weight-reducing properties increased over the study period. Conclusion The prevalence of T2DM among young adults in South Korea nearly doubled over the past decade. The strong association with obesity and metabolic comorbidities emphasizes the urgent need for targeted prevention and management strategies tailored to this population.

Background: Active surveillance (AS) has emerged as a viable management strategy for low-risk papillary thyroid microcarcinoma (PTMC), following pioneering trials at Kuma Hospital and the Cancer Institute Hospital in Japan. Numerous prospective cohort studies have since validated AS as a management option for low-risk PTMC, leading to its inclusion in thyroid cancer guidelines across various countries. From 2016 to 2020, the Multicenter Prospective Cohort Study of Active Surveillance on Papillary Thyroid Microcarcinoma (MAeSTro) enrolled 1,177 patients, providing comprehensive data on PTMC progression, sonographic predictors of progression, quality of life, surgical outcomes, and cost-effectiveness when comparing AS to immediate surgery. The second phase of MAeSTro (MAeSTro-EXP) expands AS to low-risk papillary thyroid carcinoma (PTC) tumors larger than 1 cm, driven by the hypothesis that overall risk assessment outweighs absolute tumor size in surgical decision-making. Methods: This protocol aims to address whether limiting AS to tumors smaller than 1 cm may result in unnecessary surgeries for low-risk PTCs detected during their rapid initial growth phase. By expanding the AS criteria to include tumors up to 1.5 cm, while simultaneously refining and standardizing the criteria for risk assessment and disease progression, we aim to minimize overtreatment and maintain rigorous monitoring to improve patient outcomes. Conclusion This study will contribute to optimizing AS guidelines and enhance our understanding of the natural course and appropriate management of low-risk PTCs. Additionally, MAeSTro-EXP involves a multinational collaboration between South Korea and Australia. This cross-country study aims to identify cultural and racial differences in the management of low-risk PTC, thereby enriching the global understanding of AS practices and their applicability across diverse populations.

Background and Objectives: Certain medications are associated with ototoxicity. This study assesses drug-induced ototoxicity in South Korea by analyzing the Korean national health data. Subjects and Methods: Hospital records of National Health Insurance members from 2009 to 2016 were reviewed. Data were compared between patients with and without hearing loss (HL). Individuals with HL were identified as having a primary diagnosis code for sensorineural HL or another type of HL in at least one outpatient or inpatient record according to the International Classification of Diseases-10. Results: The members in the HL group increased slightly from 0.8% to 1.0% relative to the total sample, compared with 99.2% to 99.0% among the controls. The proportion of males in the HL group ranged from 45.6% to 47.6%, compared with 48.4% to 48.8% among the controls. The proportion of those aged ≥65 years in the HL group increased from 34.1% to 41.4%, compared with 10.6% to 13.3% among the controls. Hypertension prevalence (24.7%-25.7%) in the HL group was higher than that in the control group (12%-12.6%). Diabetes prevalence in the HL group was 10.6%-12.3%, compared with 4.4%-5.9% among the controls. The use of proton pump inhibitor components increased, particularly esomeprazole magnesium trihydrate and rabeprazole sodium, whereas the usage of pantoprazole sodium sesquihydrate and revaprazan was high initially but declined subsequently. The usage of painkillers such as acetaminophen, loxoprofen sodium, and ibuprofen remained high, and antibiotics such as cephalosporins indicated the highest usage. However, the use of penicillin antibiotics such as amoxicillin decreased significantly. Anticancer agents showed relatively low usage compared with other drug categories, whereas antihistamines showed extremely high usage across all years, with a continual increase. Conclusions These correlations and the underlying mechanisms necessitate further investigation, as several medicines have been linked to an increased risk of HL.

Purpose: This study evaluated the postoperative quality of life (QoL) after various types of gastrectomy for gastric cancer. Materials and Methods: A multicenter prospective observational study was conducted in Korea using the Korean Quality of Life in Stomach Cancer Patients Study (KOQUSS)-40, a new QoL assessment tool focusing on postgastrectomy syndrome. Overall, 496 patients with gastric cancer were enrolled, and QoL was assessed at 5 time points: preoperatively and at 1, 3, 6, and 12 months after surgery. Results: Distal gastrectomy (DG) and pylorus-preserving gastrectomy (PPG) showed significantly better outcomes than total gastrectomy (TG) and proximal gastrectomy (PG) with regard to total score, indigestion, and dysphagia. DG, PPG, and TG also showed significantly better outcomes than PG in terms of dumping syndrome and worry about cancer. Postoperative QoL did not differ significantly according to anastomosis type in DG, except for Billroth I anastomosis, which achieved better bowel habit change scores than the others. No domains differed significantly when comparing double tract reconstruction and esophagogastrostomy after PG. The total QoL score correlated significantly with postoperative body weight loss (more than 10%) and extent of resection (P<0.05 for both).Reflux as assessed by KOQUSS-40 did not correlate significantly with reflux observed on gastroscopy 1 year postoperatively (P=0.064). Conclusions Our prospective observation using KOQUSS-40 revealed that DG and PPG lead to better QoL than TG and PG. Further study is needed to compare postoperative QoL according to anastomosis type in DG and PG.

Purpose: The novel curability criteria for elderly (EL) patients have been proposed to stratify their risk of lymph node metastasis (LNM), following non-curative endoscopic submucosal dissection (ESD) for early gastric cancer (EGC). Hence, this study aimed to evaluate the effectiveness of the EL criteria and compare them with those of the well-known eCura system. Materials and Methods: A retrospective analysis was performed on 143 patients who did not meet the curative ESD criteria at a tertiary hospital in Korea between 2011 and 2022. Of these, 102 underwent additional surgery, while 41 were followed up without further treatment. The LNM rates based on the EL and eCura systems were stratified and compared. Results: In the surgery group, 29.4% (30/102) patients were classified as EL-low (EL-L) and 70.2% (72/102) as EL-high (EL-H). The LNM rates (95% confidence interval) were 0.0% (0.0–11.6) and 9.7% (4.0–19.0) for EL-L and EL-H, respectively (P=0.102). EL-L was closely aligned with the eCura low-risk category, with a similar patient proportion (32.4%) and an LNM rate of 0.0% (0.0–10.6). The eCura system classified 94.1% (48/51) of the EL-L patients as lowrisk, with an 86% concordance rate (123/143). Discordant cases included patients with positive vertical margins, but without other risk factors, who were classified as EL-H without LNM. Conclusions Patients with EL-L showed no LNM, and the EL criteria demonstrated high concordance with the eCura system. The EL criteria may be as effective as the eCura system in identifying low-risk patients after non-curative ESD for EGC.