Purpose: Claudin 18.2 (CLDN18.2) has emerged as a promising therapeutic target for CLDN18.2-expressing gastric cancer (GC). We sought to examine the heterogeneity of CLDN18.2 expression between primary GC (PGC) and metastatic GC (MGC) using various scoring methods. Materials and Methods: We retrospectively analyzed data from 102 patients with pathologically confirmed paired primary and metastatic gastric or gastroesophageal junction adenocarcinomas. CLDN18.2 expression was evaluated through immunohistochemistry on formalin-fixed paraffin-embedded tissue samples. We assessed CLDN18.2 positivity using multiple scoring approaches, including the immunoreactivity score, H-score, and the percentage of tumor cells showing moderate-to-strong staining intensity. We analyzed the concordance rates between PGC and MGC and the association of CLDN18.2 positivity with clinicopathological features. Results: CLDN18.2 positivity varied from 25% to 65% depending on the scoring method, with PGC consistently showing higher expression levels than MGC. Intratumoral heterogeneity was noted in 25.5% of PGCs and 19.6% of MGCs. Intertumoral heterogeneity, manifesting as discordance in CLDN18.2 positivity between PGC and MGC, was observed in about 20% of cases, with moderate agreement across scoring methods (κ=0.47 to 0.60).In PGC, higher CLDN18.2 positivity correlated with synchronous metastasis, presence of peritoneal metastasis, poorly differentiated grade, and biopsy specimens. In MGC, positivity was associated with synchronous metastasis, presence of peritoneal metastasis, and metastatic peritoneal tissues. Conclusions CLDN18.2 expression demonstrates significant heterogeneity between PGC and MGC, with a 20% discordance rate. Comprehensive tissue sampling and reassessment of CLDN18.2 status are crucial, especially before initiating CLDN18.2-targeted therapies.

Purpose: Since 1995, the Korean Gastric Cancer Association (KGCA) has been periodically conducting nationwide surveys on patients with surgically treated gastric cancer. This study details the results of the survey conducted in 2023. Materials and Methods: The survey was conducted from March to December 2024 using a standardized case report form. Data were collected on 86 items, including patient demographics, tumor characteristics, surgical procedures, and surgical outcomes. The results of the 2023 survey were compared with those of previous surveys. Results: Data from 12,751 cases were collected from 66 institutions. The mean patient age was 64.6 years, and the proportion of patients aged ≥71 years increased from 9.1% in 1995 to 31.7% in 2023. The proportion of upper-third tumors slightly decreased to 16.8% compared to 20.9% in 2019. Early gastric cancer accounted for 63.1% of cases in 2023.Regarding operative procedures, a totally laparoscopic approach was most frequently applied (63.2%) in 2023, while robotic gastrectomy steadily increased to 9.5% from 2.1% in 2014.The most common anastomotic method was the Billroth II procedure (48.8%) after distal gastrectomy and double-tract reconstruction (51.9%) after proximal gastrectomy in 2023.However, the proportion of esophago-gastrostomy with anti-reflux procedures increased to 30.9%. The rates of post-operative mortality and overall complications were 1.0% and 15.3%, respectively. Conclusions The results of the 2023 nationwide survey demonstrate the current status of gastric cancer treatment in Korea. This information will provide a basis for future gastric cancer research.

Gastric cancer is one of the most common cancers in both Korea and worldwide. Since 2004, the Korean Practice Guidelines for Gastric Cancer have been regularly updated, with the 4th edition published in 2022. The 4th edition was the result of a collaborative work by an interdisciplinary team, including experts in gastric surgery, gastroenterology, endoscopy, medical oncology, abdominal radiology, pathology, nuclear medicine, radiation oncology, and guideline development methodology. The current guideline is the 5th version, an updated version of the 4th edition. In this guideline, 6 key questions (KQs) were updated or proposed after a collaborative review by the working group, and 7 statements were developed, or revised, or discussed based on a systematic review using the MEDLINE, Embase, Cochrane Library, and KoreaMed database. Over the past 2 years, there have been significant changes in systemic treatment, leading to major updates and revisions focused on this area.Additionally, minor modifications have been made in other sections, incorporating recent research findings. The level of evidence and grading of recommendations were categorized according to the Grading of Recommendations, Assessment, Development and Evaluation system. Key factors for recommendation included the level of evidence, benefit, harm, and clinical applicability. The working group reviewed and discussed the recommendations to reach a consensus. The structure of this guideline remains similar to the 2022 version.Earlier sections cover general considerations, such as screening, diagnosis, and staging of endoscopy, pathology, radiology, and nuclear medicine. In the latter sections, statements are provided for each KQ based on clinical evidence, with flowcharts supporting these statements through meta-analysis and references. This multidisciplinary, evidence-based gastric cancer guideline aims to support clinicians in providing optimal care for gastric cancer patients.

Background: Hearing level reference values based on the results of recent audiometry have not been established for the general population of South Korea. This study aimed to evaluate the mean hearing levels of each age group and to measure the annual progression of hearing loss. Methods: We used the database of the eighth and ninth Korea National Health and Nutrition Examination Survey from 2020 to 2022, and included participants with normal tympanic membranes and without occupational noise exposure. Mean hearing levels were calculated by averaging hearing levels at 0.5 kHz, 1 kHz, 2 kHz, and 4 kHz. Hearing loss was defined as a hearing level exceeding 25 dB in the better ear, and severity of hearing loss was classified as moderate, moderately severe, severe, and profound, following the World Health Organization classification. Results: Hearing levels and the proportions of patients with hearing loss increased with age. Hearing levels were 9.11 ± 6.28 dB, 13.33 ± 7.85 dB, 19.90 ± 10.30 dB, and 31.95 ± 13.37 dB in those in their 40s, 50s, 60s, and 70s, respectively, and the proportions of patients with hearing loss were 1.81%, 7.51%, 25.32%, and 63.94%, respectively. The annual increase in hearing level was 0.71 dB, and increases were greater at higher frequencies. Hearing loss was also worse in men. Conclusion The present study provides reference values for normal hearing levels by age group, and indirectly reveals the progression of age-related hearing loss. Based on the results, physicians will be able to provide appropriate advice regarding hearing levels and the need for monitoring in the elderly.

Purpose: To examine the factors impacting cone contrast sensitivity in Koreans aged > 60 years who are scheduled for cataract surgery and do not have congenital color vision deficiencies. Methods: The ColorDx Cone contrast test HD® (CCT-HD; Konan Medical, Inc., CA, USA) was administered to 33 Korean individuals (33 eyes) to evaluate CCT scores before and after cataract surgery, as well as changes in CCT scores according to the degree of progression by cataract type. Correlations between CCT scores and age, best corrected visual acuity (BCVA), regional retinal thickness, and length of the photoreceptor outer segment (PROS) at the fovea were analyzed in pseudophakic eyes. Results: Average scores for short-, medium-, and long-wavelength cone contrast sensitivity tests (S-CCT, M-CCT, and L-CCT, respectively) improved after surgery (p = 0.010, p = 0.001, and p = 0.028, respectively). Comparing CCT score changes before and after surgery by cataract progression, higher cataract grades were associated with greater CCT score changes, though the differences were not statistically significant (p > 0.05). In pseudophakic eyes, S-CCT scores negatively correlated with age (p = 0.017). No significant correlations were found between S-CCT, M-CCT, and L-CCT scores and BCVA, whereas S-CCT, M-CCT, and L-CCT scores positively correlated with PROS at the fovea (p < 0.001). Conclusions Cone contrast sensitivity in individuals aged > 60 years is influenced by age and cataract status and may serve as a valuable indicator of visual function in clinical research.

Purpose: To examine the factors impacting cone contrast sensitivity in Koreans aged > 60 years who are scheduled for cataract surgery and do not have congenital color vision deficiencies. Methods: The ColorDx Cone contrast test HD® (CCT-HD; Konan Medical, Inc., CA, USA) was administered to 33 Korean individuals (33 eyes) to evaluate CCT scores before and after cataract surgery, as well as changes in CCT scores according to the degree of progression by cataract type. Correlations between CCT scores and age, best corrected visual acuity (BCVA), regional retinal thickness, and length of the photoreceptor outer segment (PROS) at the fovea were analyzed in pseudophakic eyes. Results: Average scores for short-, medium-, and long-wavelength cone contrast sensitivity tests (S-CCT, M-CCT, and L-CCT, respectively) improved after surgery (p = 0.010, p = 0.001, and p = 0.028, respectively). Comparing CCT score changes before and after surgery by cataract progression, higher cataract grades were associated with greater CCT score changes, though the differences were not statistically significant (p > 0.05). In pseudophakic eyes, S-CCT scores negatively correlated with age (p = 0.017). No significant correlations were found between S-CCT, M-CCT, and L-CCT scores and BCVA, whereas S-CCT, M-CCT, and L-CCT scores positively correlated with PROS at the fovea (p < 0.001). Conclusions Cone contrast sensitivity in individuals aged > 60 years is influenced by age and cataract status and may serve as a valuable indicator of visual function in clinical research.

This study introduces a novel biportal endoscopic foraminal decompression technique that minimizes bone removal while ensuring safe and effective nerve root decompression. Leveraging the accessory process as a key surgical landmark, this technique enables precise navigation and controlled turn-down of the ligamentum flavum (LF). A key advantage of this technique is its reduced requirement for bone resection, differing from traditional microscopic or uniportal endoscopic surgeries that often necessitate resection of the lateral isthmus or superior articular process. This technique is particularly beneficial for foraminal and extraforaminal herniated nucleus pulposus cases, where bony decompression needs are relatively lower compared to foraminal stenosis. Using the accessory process as a landmark also enhances surgical precision and reduces the risk of nerve root injury, providing a valuable advantage for less experienced surgeons. Despite these advantages, challenges exist, particularly at the L5–S1 level, where the less prominent accessory process and limited workspace due to anatomical constraints can pose difficulties. In cases of severe bony compression, additional bone removal may be necessary to achieve adequate decompression. In conclusion, the Non-facetectomy LF turn-down technique (non-facetectomy foraminal decompression) offers a safe and effective minimally invasive alternative for treating various foraminal pathologies.

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: Diabetes in older adults is becoming a significant public burden to South Korea. However, a comprehensive understanding of epidemiologic trends and the detailed clinical characteristics of older adults with diabetes is lacking. Therefore, we evaluated epidemiologic trends and the metabolic and lifestyle characteristics of diabetes in Korean older adults. Methods: We analyzed data from the Korea National Health and Nutrition Examination Survey to assess diabetes prevalence according to diabetes duration and lifestyle behaviors. In addition, we drew upon the National Health Information Database of the National Health Insurance System to assess physical activity levels, antidiabetic medication use, polypharmacy, medication adherence, and major comorbidities. Results: The absolute number of newly diagnosed cases of diabetes among older adults doubled over the past decade. Management rates of metabolic indicators were higher in older adults with diabetes compared to those without diabetes. The proportion of older adults with diabetes meeting the minimum recommended physical activity increased over the years. Compared to 10 years before, the use of dipeptidyl peptidase-4 inhibitor or sodium-glucose cotransporter-2 inhibitor had increased, as had comorbidities such as dyslipidemia, dementia, cancer, heart failure, atrial fibrillation, and chronic kidney disease. Initial medication adherence was significantly lower in those with end-stage kidney disease or dementia, insulin use, high-risk alcohol use, and living alone. Continuing insulin use 1 year after diagnosis of diabetes was significantly higher in those who initiated insulin therapy at diagnosis, had retinopathy, were on triple antidiabetic medications, and had a history of cancer. Conclusion Comprehensive management of metabolic indicators and physical activity is essential for older adults with diabetes. Improvements in prescribing guidelines, personalized management of age-related comorbidities, and individualized approaches that consider the heterogeneous nature of older adults with diabetes are desirable. Further research, such as high-quality cohort and intervention studies specific to older adults, is needed to establish evidence-based management for older adults with diabetes.