This study offers a comprehensive overview of brain organoids for researchers. It combines expert opinions with technical summaries on organoid definitions, characteristics, culture methods, and quality control. This approach aims to enhance the utilization of brain organoids in research. Brain organoids, as three-dimensional human cell models mimicking the nervous system, hold immense promise for studying the human brain. They offer advantages over traditional methods, replicating anatomical structures, physiological features, and complex neuronal networks. Additionally, brain organoids can model nervous system development and interactions between cell types and the microenvironment. By providing a foundation for utilizing the most human-relevant tissue models, this work empowers researchers to overcome limitations of two-dimensional cultures and conduct advanced disease modeling research.

Gastric cancer is one of the most common cancers in Korea and the world. Since 2004, this is the 4th gastric cancer guideline published in Korea which is the revised version of previous evidence-based approach in 2018. Current guideline is a collaborative work of the interdisciplinary working group including experts in the field of gastric surgery, gastroenterology, endoscopy, medical oncology, abdominal radiology, pathology, nuclear medicine, radiation oncology and guideline development methodology. Total of 33 key questions were updated or proposed after a collaborative review by the working group and 40 statements were developed according to the systematic review using the MEDLINE, Embase, Cochrane Library and KoreaMed database. The level of evidence and the grading of recommendations were categorized according to the Grading of Recommendations, Assessment, Development and Evaluation proposition. Evidence level, benefit, harm, and clinical applicability was considered as the significant factors for recommendation. The working group reviewed recommendations and discussed for consensus. In the earlier part, general consideration discusses screening, diagnosis and staging of endoscopy, pathology, radiology, and nuclear medicine. Flowchart is depicted with statements which is supported by meta-analysis and references. Since clinical trial and systematic review was not suitable for postoperative oncologic and nutritional follow-up, working group agreed to conduct a nationwide survey investigating the clinical practice of all tertiary or general hospitals in Korea. The purpose of this survey was to provide baseline information on follow up. Herein we present a multidisciplinary-evidence based gastric cancer guideline.

Background: The aims of this study are to review data on 4-months age National Health Screening Program for Infants and Children (NHSPIC) using a National Health Insurance Service (NHIS) database, and to analyze the newborn hearing screening (NHS) results and related characteristics of the 4-months NHSPIC for 7 years in South Korea. Methods: We analyzed a NHIS database of infants who had participated in the 4-month age NHSPIC from 2010 to 2016. According to the results of hearing questionnaires and physical examination, we analyzed the outcomes of NHS and related infantile and socioeconomic factors. Results: Among 3,128,924 of total eligible infants in Korea between the year 2010 and 2016, 69.2% (2,164,621 infants) conducted 4-months age NHSPIC, and 94.4% (2,042,577 infants) of which performed hearing questionnaires regarding NHS. Among the total hearing examinees, premature infants accounted for 3.6%, infants who were hospitalized in the neonatal intensive care unit (NICU) for more than 5 days accounted for 5.6%, and infants with head and neck abnormalities were 0.6%. The NHS performing rate was 79.1% for total hearing examinees in 2010, but gradually increased to 88.9% in 2016. The NHS performing rate in 2016 was 93.4% for premature infants, 91.7% for NICU hospitalized babies. The mean referral rate was 0.6% for total hearing examinees, 1.4% for premature infants, and 2.3% for NICU hospitalized babies. When we analyzed the NHS performing rate and the referral rate according to the household income level, the NHS performing rate of infants in Medical Aid programs was the lowest as 65.6%, and the NHS performing rates in other five levels of NHIS was higher ranging between 85.1% to 86.0%. The referral rate of infants in the Medical Aid program (3.8%) was significantly higher than those of infants in other classes (1.10–1.25%). Conclusion The estimated overall NHS performing rate in Korea gradually increased and was 88.9% in 2016. The overall referral rate was low as 0.6%, and it was significantly different depending on the infant’s health condition and household income levels. We assume that our finding would help to establish policies managing hearing impaired children, and to develop the customized hearing care service programs considering the household economic levels.

Background: Korea recently established 70 emergency medical service areas. However, there are many concerns that medical resources for stroke could not be evenly distributed through the country. We aimed to compare the treatment quality and outcomes of acute stroke among the emergency medical service areas. Methods: This study analyzed the data of 28,800 patients admitted in 248 hospitals which participated in the 8th acute stroke quality assessment by Health Insurance Review and Assessment Service. Individual hospitals were regrouped into emergency service areas according to the address of the location. Assessment indicators and fatality were compared by the service areas. We defined the appropriate hospital by the performance of intravenous thrombolysis. Results: In seven service areas, there were no hospitals which received more than 10 stroke patients for 6 months. In nine service areas, there were no patients who underwent intravenous thrombolysis (IVT). Among 167 designated emergency medical centers, 50 hospitals (29.9%) responded that IVT was impossible 24 hours a day. There are 97 (39.1%) hospitals that meet the definitions of appropriate hospital. In 23 service areas (32.9%) had no appropriate or feasible hospitals. The fatality of service areas with stroke centers were 6.9% within 30 days and 15.6% within 1 year from stroke onset than those without stroke centers (7.7%, 16.9%, respectively). Conclusions There was a wide regional gap in the medical resource and the quality of treatments for acute stroke among emergency medical service areas in Korea. The poststroke fatality rate of the service areas which have stroke centers or appropriate hospitals were significantly low.

Background/Aims: Patients with inflammatory bowel disease (IBD) are diagnosed with ankylosing spondylitis (AS) often. However, the disease course of patients with both IBD and AS is not well understood. This study aims to evaluate the effect of concomitant AS on IBD outcomes. Methods: Among the 4,722 patients with IBD who were treated in 3 academic hospitals from 2004 to 2021, 55 were also diagnosed with AS (IBD-AS group). Based on patients’ electronic medical records, the outcomes of IBD in IBD-AS group and IBD group without AS (IBD-only group) were appraised. Results: The proportion of patients treated with biologics or small molecule therapies was significantly higher in IBD-AS group than the proportion in IBD-only group (27.3% vs. 12.7%, P= 0.036). Patients with both ulcerative colitis and AS had a significantly higher risk of biologics or small molecule therapies than patients with only ulcerative colitis (P< 0.001). For univariable logistic regression, biologics or small molecule therapies were associated with concomitant AS (odds ratio, 4.099; 95% confidence interval, 1.863–9.021; P< 0.001) and Crohn’s disease (odds ratio, 3.552; 95% confidence interval, 1.590–7.934; P= 0.002). Conclusions Concomitant AS is associated with the high possibility of biologics or small molecule therapies for IBD. IBD patients who also had AS may need more careful examination and active treatment to alleviate the severity of IBD.

Purpose: Cancer antigen 15-3 (CA15-3) is a serum tumor marker for breast cancer (BC) extensively used in clinical practice. CA15-3 is non-invasive, easily available, and a costeffective tumor marker for immediate diagnosis, monitoring and prediction of BC recurrence. We hypothesized that an elevation of CA15-3 may have prognostic impact in patients with early BC with normal serum CA15-3 level. Methods: This was a retrospective cohort study, which included patients with BC who received curative surgery at a comprehensive single institution between 2000 and 2016.CA15-3 levels from 0 to 30 U/mL were considered normal, and patients who had CA15-3 > 30 U/mL, were excluded from the study. Results: The mean age of study participants (n = 11,452) was 49.3 years. The proportion of participants with elevated CA15-3 ≥ 1 standard deviation (SD) compared with the previous examination during follow-up was 23.3% (n = 2,666). During the follow-up (median followup 5.8 years), 790 patients experienced recurrence. The fully-adjusted hazard ratio (HR) for recurrence comparing participants with stable CA15-3 level to subjects with elevated CA15-3 level was 1.76 (95% confidence interval [CI], 1.52–2.03). In addition, if the CA15-3was elevated ≥ 1 SD, the risk was much higher (HR, 6.87; 95% CI, 5.81–8.11) than in patients without elevated CA15-3 ≥ 1 SD. In sensitivity analysis, the recurrence risk was consistently higher in participants with elevated CA15-3 levels than in participants without elevated CA15-3 levels. The association between elevated CA15-3 levels and incidence of recurrence was observed in all subtypes and the association was stronger in patients with N+ than in patients with N0 stage (p-value for interaction < 0.01). Conclusion The results of the present study demonstrated that elevation of CA15-3 in patients with early BC and initial normal serum CA15-3 levels has a prognostic impact.

Background/Aims: Owing to the low prevalence of small-bowel adenocarcinoma (SBA), data on the impact of Crohn’s disease (CD) on the survival of patients with SBA are lacking. Therefore, we investigated this issue in this study. Methods: In this bicenter cohort study, patients with histologically confirmed SBA were retrospectively enrolled and classified into two groups: sporadic SBA and CD-associated SBA. Patients with duodenal SBA were excluded. Overall survival, disease-free survival, and factors associated with survival were analyzed. Results: Of 128 patients with SBA, 115 had sporadic SBA and 13 had CD-associated SBA. Ileal involvement and poorly differentiated tumors were more common in the CD-associated SBA group than in the sporadic SBA group (ileal involvement, 53.8% vs 22.6%; poor differentiation, 46.2% vs 14.8%; both p<0.05). In survival analysis, overall survival showed no statistical difference between the sporadic SBA and CD-associated SBA groups (p=0.370). However, when stratified by stage, the adjusted overall survival of the CD-associated SBA group was lower in patients with an advanced disease stage (p=0.029). Disease-free survival showed the same tendency, albeit without clinical significance (p=0.097). CD (hazard ratio [HR], 2.308; p=0.047), older age (≥65 yr) at SBA diagnosis (HR, 2.766; p=0.001), and stage III/IV disease (HR, 3.151; p<0.001) were factors associated with mortality. Conclusions The overall survival of patients with CD-associated SBA did not differ from that of patients with sporadic SBA. However, as CD is an independent risk factor for mortality, vigilant surveillance in high-risk patients may be crucial.

Background/Aims: Infectious complications are major concerns when treating patients with inflammatory bowel disease (IBD). This study evaluated clinical differences across countries/regions in the management of infectious diseases in patients with IBD. Methods: A multinational online questionnaire survey was administered to participants at the 8th meeting of the Asian Organization for Crohn’s and Colitis. The questionnaire included questions regarding surveillance, diagnosis, management, and prevention of infection in patients with IBD. Results: A total of 384 physicians responded to the questionnaire. The majority of Korean (n=70, 63.6%) and Chinese (n=51, 51.5%) physicians preferred vancomycin to metronidazole in the treatment of Clostridium difficile infection, whereas more than half of the Japanese physicians (n=62, 66.7%) preferred metronidazole. Physicians in Korea (n=88, 80.0%) and China (n=46, 46.5%) preferred a 3-month course of isoniazid and rifampin to treat latent tuberculosis infection, whereas most physicians in Japan (n=71, 76.3%) favored a 9-month course of isoniazid. Most Korean physicians (n=89, 80.9%) recommended hepatitis B virus (HBV) vaccination in patients lacking HBV surface antigen, whereas more than half of Japanese physicians (n=53, 57.0%) did not consider vaccination. Conclusions Differences in the diagnosis, prevention, and management of infections in patients with IBD across countries/regions reflect different prevalence rates of infectious diseases. This survey may broaden understanding of the real-world clinical settings across Asian countries/regions and provide information for establishing practical guidelines to manage patients with IBD.

Background: and Purpose The importance of the quality of life (QOL) of carers has been increasingly recognized as it has a wide range of effects on the psychological, emotional, and social outcomes of patients with Parkinson’s disease (PD). Understanding their QOL is important as it reflects their unique characteristics; however, there have been few studies on this in Korea. This study aimed to translate and validate the Korean version of the Parkinson’s Disease Questionnaire–Carer (PDQ-Carer). Methods: This was a methodological study that included a translation process and a crosssectional investigation. The Korean version of the scale was developed using back translation, semantic adjustment, and pretests. The final version was self-administered by 125 Korean family carers. Cronbach’s alpha values were used to assess the internal consistency of the PDQ-Carer. Exploratory and confirmatory factor analyses were used to validate the translated scale. Results: Exploratory factor analysis identified four factors that accounted for 64.51% of the variance. A modified model using modification indices was found to fit the data well in the confirmatory factor analysis. That factor analysis supported the structure of the original four factors with relocation of several items that reflected Korean culture. Cronbach’s alpha values were 0.96 for the total scale, 0.93 for personal and social activities, 0.89 for strain, 0.85 for anxiety and depression, and 0.85 for self-care. Conclusions This study verified that the Korean version of the PDQ-Carer can be used to acquire important information about the multidimensional aspects of the QOL of Korean carers for patients with PD.