Irritable bowel syndrome (IBS) is a chronic, disabling, and functional bowel disorder that significantly affects social functioning and reduces quality of life and increases social costs. The Korean Society of Neurogastroenterology and Motility published clinical practice guidelines on the management of IBS based on a systematic review of the literature in 2017, and planned to revise these guidelines in light of new evidence on the pathophysiology, diagnosis, and management of IBS. The current revised version of the guidelines is consistent with the previous version and targets adults diagnosed with or suspected of having IBS. These guidelines were developed using a combination of de novo and adaptation methods, with analyses of existing guidelines and discussions within the committee, leading to the identification of key clinical questions. Finally, the guidelines consisted of 22 recommendations, including 3 concerning the definition and risk factors of IBS, 4 regarding diagnostic modalities and strategies, 2 regarding general management, and 13 regarding medical treatment. For each statement, the advantages, disadvantages, and precautions were thoroughly detailed. The modified Delphi method was used to achieve expert consensus to adopt the core recommendations of the guidelines. These guidelines serve as a reference for clinicians (including primary care physicians, general healthcare providers, medical students, residents, and other healthcare professionals) and patients, helping them to make informed decisions regarding IBS management.

Background: Primary Merkel cell carcinoma of the salivary gland is currently not listed in the World Health Organization classification. However, cases of Merkel cell type neuroendocrine carcinomas of the salivary gland with perinuclear cytokeratin 20 positivity have been intermittently reported. We here investigated the clinicopathologic features of additional cases. Methods: Data of four cases of Merkel cell type small cell neuroendocrine carcinoma of the salivary gland were retrieved. To confirm the tumors’ primary nature, clinical records and pathologic materials were reviewed. Optimal immunohistochemical staining was performed to support the diagnosis. Results: All tumors were located in the parotid gland. Possibilities of metastasis were excluded in all cases through a meticulous clinicopathological review. Tumor histology was consistent with the diagnosis of small cell neuroendocrine carcinoma. Tumors’ immunohistochemical phenotypes were consistent with Merkel cell carcinoma, including Merkel cell polyomavirus large T antigen positivity in two of the four cases. Conclusions Merkel cell carcinomas can originate in salivary glands and are partly associated with Merkel cell polyomavirus infection as in cutaneous Merkel cell carcinomas.

The prevalence of obesity is increasing rapidly around the world. The World Cancer Research Fund/American Institute for Cancer Research has reported that obesity raises the risk of several cancers, including esophageal, pancreatic, liver, colorectal, and breast cancers. Consequently, maintaining a healthy body weight is recommended for cancer prevention. In this article, the concept of the population attributable fraction (PAF) of cancer due to excess body weight is introduced, along with the methods for estimating the PAF, and the resulting values are compared across different countries.Current Concepts: The PAF quantifies the extent to which obesity contributes to the development of each cancer type. A recent study estimated that in 2015 the PAF for cancer due to obesity was 2.40% for men and 3.29% for women. Because the calculation relies on obesity prevalence data from over 10 years earlier, current obesity rates will influence future PAF values. As obesity has increased significantly in Korea, the burden of obesity-related cancers is expected to rise. Although Korea’s PAF is lower than that reported in Western countries, it is higher than that in other Asian nations.Discussion and Conclusion: With the growing prevalence of obesity, the incidence of obesity-related cancers is projected to increase. Effective obesity management is therefore essential for cancer prevention.

A fundamental objective of public health is to identify the causes of diseases and associated risk factors to develop effective prevention strategies. In this regard, the population attributable fraction (PAF) has become a key epidemiological measure for quantifying the proportion of disease incidence in a population attributable to specific risk factors.Current Concepts: The concept of PAF is widely applied in epidemiological and public health research, playing a crucial role in prioritizing disease prevention and management strategies. Estimating the PAF of cancer risk factors based on national data provides essential evidence for the formulation of government-led cancer control policies and prevention strategies. In particular, these estimates serve as critical indicators for evaluating cancer control programs and informing policy decisions. Given the variations in risk factor prevalence across different populations, it is crucial to estimate PAF using country-specific data to ensure the development of tailored and effective public health interventions.Discussion and Conclusion: This study underscores the importance of PAF as a foundational tool for evidencebased policymaking and highlights the need for periodic reassessment to enhance the effectiveness of cancer prevention and control efforts.

Radiofrequency ablation (RFA) is a minimally invasive treatment modality used as an alternative to surgery in patients with benign thyroid nodules, recurrent thyroid cancers (RTCs), and primary thyroid microcarcinomas. The Korean Society of Thyroid Radiology (KSThR) initially developed recommendations for the optimal use of RFA for thyroid tumors in 2009 and revised them in 2012 and 2017. As new meaningful evidence has accumulated since 2017 and in response to a growing global interest in the use of RFA for treating malignant thyroid lesions, the task force committee members of the KSThR decided to update the guidelines on the use of RFA for the management of RTCs based on a comprehensive analysis of current literature and expert consensus.

Purpose: Congenital hypothyroidism (CH) is a major preventable cause of intellectual disability, particularly in very low birth weight (VLBW) infants, who are at increased risk due to hypothalamic-pituitary-thyroid axis immaturity. Early differentiation between transient CH (TCH) and permanent CH (PCH) is crucial to optimize L-thyroxine (LT4) treatment duration. This study aimed to determine the incidence of PCH among Korean VLBW infants and to identify clinical factors that may aid in distinguishing TCH from PCH. Methods: This retrospective cohort study included VLBW infants diagnosed with CH and treated with LT4 at a single tertiary neonatal intensive care unit between 2011 and 2020. Infants requiring LT4 beyond 3 years were classified as PCH, while those who discontinued earlier were considered TCH. Clinical characteristics, neonatal morbidities, and thyroid-related parameters were compared between the groups. Results: Among 1,292 VLBW infants, 122 (9.4%) were diagnosed with CH. After excluding deaths and those lost to follow-up, 73 infants were included in the final analysis (TCH, n=50; PCH, n=23). The PCH group had a significantly higher mean gestational age and greater LT4 requirements at both 12 and 36 months of age. Major anomalies were more frequently observed in PCH infants, including congenital heart defects. In multivariate analysis, higher gestational age, the presence of major anomalies, screening thyroid-stimulating hormone (TSH) >10 μIU/mL, and higher LT4 dose at 36 months were significantly associated with PCH. Conclusion The incidence of PCH in Korean VLBW infants was relatively higher than that reported in previous studies studies. Screening TSH level and LT4 dose requirements may support individualized follow-up and help distinguish PCH from TCH.

Extracellular vesicles (EVs) are lipid bilayer-enclosed particles that contain diverse molecular components, such as proteins, nucleic acids, and lipids. EVs reflect the state of their cell of origin in intercellular communication. Such characteristics of EVs demonstrate their potential as biomarkers and therapeutic agents in basic and translational research. Research on EV biology and applications has progressed significantly. However, challenges remain in translating their potential into clinical applications because of issues in nomenclature, the separation of EVs from nonvesicular extracellular particles, and methods for characterization and functional analysis. The International Society for Extracellular Vesicles addresses the current standards and challenges in this rapidly evolving field through periodical updates of its Minimal Information for Studies of Extracellular Vesicles (MISEV), which was published in 2014 and revised in 2018. The latest revision, MISEV2023, provides an updated overview of the current methodologies, detailing their strengths and limitations in EV production, separation, and characterization from various sources, including cell cultures, body fluids, and solid tissues. In this review, we summarize the fundamental principles of EV research by referencing the guidelines on EVs published by the Ministry of Food and Drug Safety of the Republic of Korea. Furthermore, we elaborate on the key aspects of MISEV2023, providing information for domestic EV researchers in selecting or developing optimal research methodologies according to their specific objectives and applications.

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.