Objectives: In May 2025, clusters of salmonellosis were identified in 7 cities in the Republic of Korea, all associated with consumption of identical bakery products. This investigation aimed to characterize the outbreak, identify potential contributing factors, and inform strategies for preventing similar multi-facility foodborne outbreaks. Methods: A case series study was conducted among individuals who consumed Manufacturer H’s Product I and Product II on May 15–16, 2025 at 7 facilities (n = 1,235). Clinical specimens from symptomatic individuals, retained food samples, and environmental samples were collected and tested. Food-exposure histories were assessed, and active case finding was implemented across all supplied facilities. Traceback investigations were conducted at the manufacturer, distributor, and egg farms. Human and food isolates underwent pulsed-field gel electrophoresis (PFGE) and whole-genome sequencing (WGS). Results: A total of 323 cases met the outbreak case definition (attack rate, 26.2%), of which 48 were laboratory-confirmed. Salmonella Enteritidis was isolated from both clinical specimens and retained bakery products. PFGE patterns were indistinguishable between human and food isolates, and WGS demonstrated high genetic relatedness. These findings confirmed a common-source outbreak linked to the implicated bakery products. Conclusion This outbreak underscores the value of integrating epidemiological investigation, active case finding, and molecular typing to identify common food vehicles in outbreaks involving widely distributed manufactured foods. Coordinated collaboration between public health and food safety authorities is essential for the effective detection, response, and prevention of multi-facility foodborne outbreaks.

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.

Purpose: Endoscopic submucosal dissection (ESD) has become a standard minimally invasive treatment for selected patients with early gastric cancer (EGC). This study presents the first nationwide survey of patients with EGC treated with ESD in 2023, conducted by the Korean College of Helicobacter and Upper Gastrointestinal Research. Materials and Methods: Data were retrospectively collected from participating referral centers across Korea using a standardized case report form covering patient characteristics, tumor features, procedural details, histopathological findings, and clinical outcomes.Descriptive and comparative analyses were conducted to summarize nationwide ESD practice patterns and outcomes. Results: Data from 5,460 ESD cases from 5,250 patients across 27 institutions were analyzed. The mean age was 67.4 years, with 74.1% males. Multiple synchronous lesions were identified in 3.7%. Most lesions were located in the lower third of the stomach (64.0%), and differentiated-type adenocarcinomas accounted for 87.8%. The en bloc and complete resection rates were 99.2% and 91.4%, respectively. Curative resection was achieved in 80.5%, whereas local non-curative resection (L-NCR) and surgical non-curative resection (S-NCR) were identified in 2.8% and 16.7%, respectively. Additional surgery was performed more frequently in patients with S-NCR than in those with L-NCR (59.3% vs. 24.7%). The bleeding and perforation rates were 3.6% and 0.9%, respectively, and were mostly managed conservatively or endoscopically. The median length of hospitalization was 4.0 days. Conclusions This first nationwide survey provides a comprehensive overview of the current practice of EGC treatment using ESD in Korea, demonstrating high technical success and safety, and establishing a baseline dataset for future longitudinal research.

Probiotics have gained increasing clinical attention as adjunctive treatment for lower gastrointestinal disorders. However, evidence supporting their therapeutic efficacy remains limited, particularly with regard to sex-related differences. This expert review provides evidence-based insights and practical recommendations for the use of probiotics in patients with irritable bowel syndrome (IBS), functional constipation (FC), and Clostridioides difficile infection (CDI), considering possible sex-related differences. Evidence from randomized controlled trials and meta-analyses indicates that probiotics can modestly improve global symptoms, abdominal pain, and bloating in IBS and enhance bowel movement frequency and stool consistency in FC. However, these effects are strain-specific and heterogeneous. Although clinical studies on probiotics in IBS have not confirmed significant sex-related differences, experimental animal studies using stress-induced IBS models have demonstrated sex-dependent responses to specific probiotic strains, supporting the biological plausibility of such differences. For CDI, the efficacy of probiotics in preventing primary or recurrent infections remains inconsistent across large trials, and current guidelines usually do not recommend their routine use. However, sex and age difference of immunology supports the clinical differences of CDI. Probiotics are generally considered safe for healthy individuals, although caution is advised in patients who are immunocompromised or critically ill. Clinicians should select probiotic products based on strain-specific clinical evidence, adequate viable doses, patient's characteristics, or patient’s sex. In conclusion, probiotics might play a role as adjunctive therapy for IBS and FC, with variability in responses influenced by microbial, host, and potential sex-related factors. Further research is needed to establish optimized personalized probiotic strategies.

Objective: To evaluate the diagnostic performance of the “probable hepatocellular carcinoma (HCC)” category in the Korean Liver Cancer Association-National Cancer Center (KLCA-NCC) v2022 guidelines. Materials and Methods: This multicenter retrospective study included patients at risk of HCC who underwent gadoxetic acid-enhanced MRI between January 2015 and June 2018; a subgroup of these patients also underwent liver CT. Eligible patients had at least one non-cystic lesion (≥10 mm) with a reference standard. Four radiologists interpreted the images independently and the results were pooled. The performance of “definite HCC” and “probable HCC” together and “probable HCC” alone were compared between v2018 and v2022. Results: A total of 2,237 patients (1,666 men; mean age, 59 ± 11 years) with 2,445 lesions were included. In v2022, 1.5% (143/9,780) of the lesions were additionally categorized as “probable HCC” by four reviewers on MRI; among these, 104 lesions were not HCCs. Focal nodular hyperplasia (FNH) or FNH-like nodules constituted 90.4% (94/104) of the false positives. When “definite HCC” and “probable HCC” were combined, v2022 showed higher sensitivity (83.7% [5,670/6,776] vs. 83.1% [5,631/6,776]) but lower specificity (77.1% [2,316/3,004] vs. 80.6% [2,420/3,004]) than v2018 (P < 0.001). For “probable HCC” alone, v2022 showed a lower positive predictive value (PPV) than v2018 (64.1% [373/582] vs. 76.1% [334/439], P < 0.001). In v2022, lesions with non-rim arterial-phase hyperenhancement (APHE) showed a lower PPV than those without APHE (42.3% [91/215] vs. 76.8% [282/367], P < 0.001). In the CT subgroup (n = 1,590), 1.6% (99/6,360) of the lesions were reassessed as “probable HCC,” and its PPV was 83.8% (83/99) in v2022 whereas no lesions were classified as “probable HCC” under v2018. Conclusion The revised “probable HCC” category in the KLCA-NCC v2022 aligns with updates in the diagnostic flow, demonstrating acceptable performance on MRI and CT. Notably, FNH or FNH-like nodules can be misclassified as “probable HCC” when MRI is used.

Probiotics have gained increasing clinical attention as adjunctive treatment for lower gastrointestinal disorders. However, evidence supporting their therapeutic efficacy remains limited, particularly with regard to sex-related differences. This expert review provides evidence-based insights and practical recommendations for the use of probiotics in patients with irritable bowel syndrome (IBS), functional constipation (FC), and Clostridioides difficile infection (CDI), considering possible sex-related differences. Evidence from randomized controlled trials and meta-analyses indicates that probiotics can modestly improve global symptoms, abdominal pain, and bloating in IBS and enhance bowel movement frequency and stool consistency in FC. However, these effects are strain-specific and heterogeneous. Although clinical studies on probiotics in IBS have not confirmed significant sex-related differences, experimental animal studies using stress-induced IBS models have demonstrated sex-dependent responses to specific probiotic strains, supporting the biological plausibility of such differences. For CDI, the efficacy of probiotics in preventing primary or recurrent infections remains inconsistent across large trials, and current guidelines usually do not recommend their routine use. However, sex- and age-related immunologic differences support the clinical differences of CDI. Probiotics are generally considered safe for healthy individuals, although caution is advised in patients who are immunocompromised or critically ill. Clinicians should select probiotic products based on strain-specific clinical evidence, adequate viable doses, patient characteristics and sex. In conclusion, probiotics might play a role as adjunctive therapy for IBS and FC, with variability in responses influenced by microbial, host, and potential sex-related factors. Further research is needed to establish optimized personalized probiotic strategies.

Purpose: While MRI-based tumor regression grade (mrTRG) has shown promise in evaluating pathologic response to concurrent chemoradiotherapy (CCRT) in rectal cancer, its ability to predict pathologic complete response remains limited.This study aimed to enhance mrTRG’s diagnostic performance in predicting ypT0–1N0 status, a key factor in considering non-radical management after CCRT for locally advanced rectal cancer (LARC). Methods: This retrospective study included 430 patients with LARC who underwent radical resection following CCRT at a single referral hospital between April 2018 and September 2024. Multivariable logistic regression was used to identify predictive factors associated with achieving ypT0–1N0 status. The diagnostic performances of mrTRG1–2 alone and in combination with other factors were assessed by comparing sensitivity, specificity, positive-predictive value (PPV), negative-predictive value, and area under the curve (AUC). Results: Ninety-three patients (21.6%) achieved ypT0–1N0. In the multivariable analysis, fungating type, cT1–2, and mrTRG1–2 were independent predictors for ypT0–1N0. Integrating mrTRG with gross tumor type yielded the highest AUC of 0.689 among the combined models. For predicting ypT0–1N0, the combination of mrTRG and gross tumor type improved PPV (79.2% vs. 41.5% for mrTRG alone) while also demonstrating enhanced sensitivity compared with ycT0–1N0, the conventional MRI-based predictor (40.9% vs. 22.6%). Conclusion This study demonstrated that combining mrTRG and gross tumor type improved the PPV of mrTRG in predicting ypT0–1N0 after CCRT in LARC. Further studies are warranted to validate the role of gross tumor type in refining predictive systems for selecting candidates for non-radical treatment.

Purpose: Distant metastasis of breast cancer significantly affects the prognosis. Serum markers such as CEA and cancer antigen (CA) 15-3 are used for surveillance. However, the nonspecificity and nonmalignant elevation of CEA limit its absolute value in predicting metastatic recurrence. We reevaluated the clinical value of CEA kinetics in predicting metastatic recurrence in breast cancer. Methods: In this multicenter retrospective cohort study, we utilized electronic medical record data from eight institutions (2008–2023), including 4,872 surgically treated patients with invasive breast cancer. Novel CEA kinetic indices were defined.Predictive capabilities were assessed using logistic regression, Kaplan-Meier survival curves, and Cox proportional hazards models. Results: CEA velocity (vCEA) and last-interval vCEA (vCEA-L) showed higher accuracy and sensitivity in predicting distant metastasis than absolute CEA indices. All tumor marker indices were independent predictors; vCEA, vCEA-L, and maximum vCEA (vCEAmax) showed the highest association. In the 5-year distant disease-free survival analysis of patients, vCEA showed the most significant difference based on whether its cutoff value was exceeded (84.1% vs. 47.2%) (P < 0.001).Cox analysis showed that vCEA was the strongest predictor (hazard ratio, 4.509; P < 0.001). vCEAmax remained prognostic even when CEAmax was below its cutoff value. Conclusion Analysis of dynamic CEA changes, particularly velocity-based indices, offers superior predictive power than the static-based CEA indices for metastatic recurrence in breast cancer. These kinetic markers enhance prognostic accuracy when combined with CA 15-3. Future research should integrate these markers with imaging, liquid biopsy, and artificial intelligence for personalized follow-up.

Objective: To classify life stages for companion dogs and cats by identifying clusters in age-specific disease proportions derived from medical records, providing a data-driven foundation for health examination programs. Methods: We collected 505,667 medical records from 82 veterinary facilities in South Korea between 2020 and 2023. Diagnoses were standardized using GPT-4o and S-BioBERT. Following preprocessing, data from 27 facilities yielded 222,706 canine and 39,910 feline records for the final analysis. Principal component analysis and K-means clustering (K = 4) were applied to age-specific disease proportions to identify life stages.The 10 most highest-proportion diagnoses diseases were determined for each cluster. Results: Canine life stages were classified as ≤ 1 year, 2–5 years, 6–10 years, and 11–15+ years.Feline life stages were 1–2 years, 3–8 years, 9–12 years, and 13–15+ years. In dogs, developmental diseases were common in the youngest age group, while chronic diseases were more prevalent in older groups. In cats, oral and urinary diseases were high-ranking, conjunctivitis was most common in the early stage, and chronic diseases increased with age. Conclusions and Relevance: Age-specific diagnosis patterns support four practical life stages for dogs and cats in South Korea. These boundaries can inform evidence-based preventive examination schedules, animal health policy, and pet insurance product design.

Background: With the aging population and advancements in medical care worldwide, the number of older patients with end-stage kidney disease continues to rise. This study aimed to identify factors associated with osteoporosis and osteopenia in older patients undergoing incident hemodialysis and assess their impact on mortality. Methods: We analyzed a large multicenter retrospective cohort of patients aged ≥70 years undergoing incident hemodialysis to identify factors associated with osteoporosis using logistic regression analysis and to assess the association of death with osteoporosis and osteopenia using Cox multivariable analysis. Results: Among 710 patients, 39.0% and 19.6% had osteoporosis and osteopenia, respectively. Osteoporosis was significantly associated with female sex, a history of fractures, and the absence of phosphate binder use. During a median follow-up of 36.8 months, 348 participants (58.8%) died. Mortality rates were the highest in the osteoporosis group (79.8%), followed by the osteopenia (77.2%) and normal bone mineral density (BMD) groups (35.2%). Cox regression analysis revealed that even after adjusting for covariates, the osteoporosis group was significantly associated with a higher mortality risk than the normal BMD group. Osteoporosis at the start of hemodialysis was significantly associated with higher mortality. Conclusion We should consider the importance of bone health in patients undergoing incident hemodialysis and pay attention to the use of phosphate binders and fracture prevention.