1.Gut microbiome in colorectal cancer: recent advances and clinical implications
Jun Yong HAN ; Min Jung KIM ; Ji Won PARK ; Seung-Yong JEONG
Annals of Coloproctology 2026;42(1):72-85
The gut microbiome is not just a bystander of colorectal carcinogenesis but is an active driver of colorectal cancer (CRC). CRC-associated microbiome contributes in the tumorigenesis through chronic inflammation, formation of toxic metabolite and genotoxins, oncogenic signal activation, immune evasion, and barrier disruption—all reinforcing a tumor microenvironment. In contrast, beneficial microbiome supports the barrier-immune-metabolic axis by maintaining mucosal integrity and balanced immune tone. Despite extensive studies of microbiome-based CRC biomarkers, microbiome-based CRC biomarkers have not been yet ready for routine clinical use due to variation across populations and lack of standardization of key steps such as sampling, analysis, cutoffs, and interpretation. Microbiome-based therapies aim to change the overall intestinal ecosystem rather than simply adding or removing single strains. At present, dietary modulation and prebiotics are considered supportive measures, while probiotics or synbiotics are in preclinical stage. Fecal microbiota transplantation (FMT) still faces important challenges in effectiveness, standardization and safety. By its role in reshaping the tumor–host immune environment, FMT is viewed as a potential option for cancer therapy after further development through well-controlled clinical trials with careful safety monitoring.
2.Nationwide Survey on Endoscopic Submucosal Dissection for Early Gastric Cancer in Korea: Results From the Korean College of Helicobacter and Upper Gastrointestinal Research (KCHUGR) 2023 Survey
Jae Yong PARK ; Jeong Hoon LEE ; Tae-Se KIM ; Da Hyun JUNG ; Bong Eun LEE ; Yonghoon CHOI ; Wan-Sik LEE ; Young-Il KIM ; Sun Hyung KANG ; Hyunsoo CHUNG ; Su Jin KIM ; Joon Sung KIM ; Donghoon KANG ; Su Youn NAM ; Seung Han KIM ; Hyo-Joon YANG ; Hyun LIM ; Jin LEE ; Seon-Young PARK ; Seung-Woo LEE ; Sun Moon KIM ; Sam Ryong JEE ; Dae Young CHEUNG ; Chung Hyun TAE ; Seokin KANG ; Sung Chul PARK ; Seung In SEO ; Cheol Min SHIN ; Kee Don CHOI ; Jong Yeul LEE ;
Journal of Gastric Cancer 2026;26(2):169-183
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.
3.Clinical Guidance and Practical Recommendations for Probiotic Use in Patients With Irritable Bowel Syndrome, Functional Constipation, and Clostridioides difficile Infection Considering Sex-based Differences
Yong Sung KIM ; Seon-Young PARK ; Seung Joo KANG ; Min Woo LEE ; Yonghoon CHOI ; Byung Yong KIM ; Miyoung CHOI ; Cheol Min SHIN ; Young Sun KIM ; Nayoung KIM ; Moo In PARK ;
Journal of Neurogastroenterology and Motility 2026;32(2):198-216
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.
4.Clinical guidance and practical recommendations for probiotic use in patients with irritable bowel syndrome, functional constipation, and Clostridioides difficile infection considering sex-based differences: a Korean translation
Yong Sung KIM ; Seon-Young PARK ; Seung Joo KANG ; Min Woo LEE ; Yonghoon CHOI ; Byung Yong KIM ; Miyoung CHOI ; Cheol Min SHIN ; Young Sun KIM ; Nayoung KIM ; Moo In PARK ;
The Ewha Medical Journal 2026;49(2):e10-
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.
5.Primary Intradural Extramedullary Ewing Sarcoma of the Thoracic Spine With Leptomeningeal and Brain Metastases:A Case Report and Literature Review
Achmad Harun MUCHSIN ; Woochan PARK ; Yu Jung KIM ; Koung Jin SUH ; Jeong Min SEO ; Kyu Sang LEE ; Keun-Yong EOM ; Seung-Jae HYUN
Brain Tumor Research and Treatment 2026;14(2):102-108
A 43-year-old woman presented with bilateral lower extremity weakness due to an intradural extramedullary spinal cord tumor. Surgery revealed Ewing sarcoma, a rare presentation known as primary intradural extramedullary Ewing sarcoma (PIEES). Despite initial treatment with radiation and chemotherapy, tumor recurrence occurred after 17 months. Further interventions included additional surgery, radiation, and chemotherapy. The disease progressed to leptomeningeal metastases along the spinal cord, prompting various treatments including targeted spinal radiation and systemic therapies. Brain metastases subsequently developed, necessitating whole-brain radiation and intrathecal chemotherapy. This case highlights the aggressive nature of PIEES, its potential for widespread leptomeningeal metastasis, and the challenges in its management, underscoring the need for multidisciplinary approaches in treating this rare and aggressive malignancy.
6.Reduced Dose and Selective Neck Irradiation Policy in Treating Oropharynx Cancer: Excellent Oncological Outcomes with Very Low Risk of Locoregional Failure
Eunyeong YANG ; Seung Gyu PARK ; Kyungmi YANG ; Dongryul OH ; Yong Chan AHN
Cancer Research and Treatment 2026;58(1):95-106
Purpose:
This study aimed to evaluate the risk of locoregional failure after reduced dose selective neck irradiation (RD-SNI) in patients with oropharyngeal cancer (OPC).
Materials and Methods:
Between 2008 and 2022, 342 OPC patients underwent definitive radiation therapy (with or without concurrent systemic therapy). The doses of 67.2-68.4 Gy to gross tumor volume (GTV), 56-60 Gy to high-risk clinical target volumes (CTV-HR), and 32-36 Gy to low-risk clinical target volumes (CTV-LR) were irradiated. The same target delineation and dosing policy were applied to all patients regardless of human papillomavirus (HPV) status. Oncological outcomes including failure patterns were also investigated.
Results:
With a median follow-up of 60.3 months (range, 1.4 to 196.6 months), the 3- and 5-year locoregional control, distant metastasis-free survival, disease-free survival, and overall survival rates were 91.6%/90.7%, 83.7%/80.7%, 78.7%/74.8%, and 91.0%/85.8%, respectively. The HPV-positive patients exhibited significantly better outcomes. Treatment failure occurred in 61 patients (17.8%); 37 (10.8%) had distant metastasis, 22 (6.4%) had local failure, and eight (2.3%) had regional failure. GTV failure was significantly more common in HPV-negative patients (p=0.003). Among the 27 patients with locoregional failure, either GTV and/or CTV-HR failure occurred in 22 (81.5%), with CTV-LR failure in one (3.7%), and out-target regional (OTR) failure in five (18.5%). Only five failures (1.5%) could be attributed to the current RD-SNI policy: one CTV-LR failure (0.3%) reflecting the RD policy and four OTR failures (1.2%) reflecting the SNI policy.
Conclusion
Excellent oncological outcomes were achieved with the current RD-SNI policy.
7.Clinical Outcomes and Use of Implantable Cardioverter-Defibrillator in Ischemic Heart Failure Patients with Reduced Ejection Fraction:A Retrospective Observational Study
Kyung Hoon CHO ; Ki Hong LEE ; Yong-Kyu LEE ; Seok OH ; Yongwhan LIM ; Joon Ho AHN ; Seung Hun LEE ; Dae Young HYUN ; Min Chul KIM ; Doo Sun SIM ; Young Joon HONG ; Ju Han KIM ; Youngkeun AHN ; Jang Hoon LEE ; Joo-Yong HAHN ; Yu-Ri KIM ; Nam Sik YOON ; Hyung Wook PARK ; Weon KIM ; Myung Ho JEONG ;
Chonnam Medical Journal 2026;62(2):55-63
Limited data exist regarding the real-world practices and clinical outcomes in patients with ischemic heart failure with reduced left ventricular ejection fractions (LVEFs).Using nationwide registry data from South Korea, we aimed to investigate long-term outcomes and clinical practices, especially implantable cardioverter defibrillators (ICDs) implantation, in patients with reduced LVEFs at least 40 days after acute myocardial infarction (AMI). Of 13,056 patients with AMI between 2011 and 2015, we analyzed 350 (median age, 66 years [interquartile range, 56-75]) who had LVEFs <40% on follow-up transthoracic echocardiogram 40 days after the index event. The primary outcome was cardiac-cause mortality at 3 years. Secondary outcomes comprised major cardiovascular events as well as outcomes defined by the use of ICDs, cardiac resynchronization therapy defibrillators (CRT-Ds), and electrophysiology studies. Among 350 patients, 39 (11.1%) died from cardiac causes during 3 years of follow-up. Eleven (3.1%) were hospitalized for ventricular tachycardia. The rate of ICD or CRT-D implantation up to 3 years was 5.7% (20/350). Cox time-to-event analysis revealed older age, LVEF <30%, diabetes mellitus, and previous MI or revascularization as positively associated with cardiac death, whereas the use of statins and body weight <67 kg were negatively associated. This nationwide Korean registry demonstrated that only 5.7% of patients who had reduced LVEFs after 40 days of AMI underwent ICD implantations over 3 years. Considering the high mortality, concerted efforts are needed to improve clinical outcomes for patients who may have been candidates for ICD implantation.
8.Intradialytic hypotension and worse outcomes in patients with acute kidney injury requiring intermittent hemodialysis
Yeong-Won PARK ; Donghwan YUN ; Yeojin YU ; Sang Hyun KIM ; Sehoon PARK ; Yong Chul KIM ; Dong Ki KIM ; Kook-Hwan OH ; Kwon Wook JOO ; Yon Su KIM ; Seong Geun KIM ; Seung Seok HAN
Kidney Research and Clinical Practice 2026;45(1):77-85
Background:
Intradialytic hypotension (IDH) is a critical complication related to worse outcomes in patients undergoing maintenance hemodialysis. Herein, we addressed the impact of IDH on mortality and other outcomes in patients with severe acute kidney injury (AKI) requiring intermittent hemodialysis.
Methods:
We retrospectively reviewed 1,009 patients who underwent intermittent hemodialysis due to severe AKI. IDH was defined as either dialysis discontinuation due to hemodynamic instability or a decrease in systolic blood pressure (BP) of ≥30 mmHg, with or without a nadir systolic BP of <90 mmHg during the first session. The primary outcome was all-cause mortality, and transfer to the intensive care unit (ICU) due to unstable status was additionally analyzed. Hazard ratios (HRs) of outcomes were calculated using a Cox regression model after adjusting for multiple variables. Risk factors for IDH were evaluated using a logistic regression model.
Results:
IDH occurred in 449 patients (44.5%) during the first hemodialysis session. Patients with IDH had a higher mortality rate than those without IDH (40% vs. 23%; HR, 1.30; 95% confidence interval [CI], 1.02–1.65). The rate of ICU transfer was higher in patients experiencing IDH than in those without IDH (17% vs. 11%; HR, 1.43; 95% CI, 1.02–2.02). Factors such as old age, high BP and pulse rate, active malignancy, cirrhosis, and hypoalbuminemia were associated with an increased risk of IDH episodes.
Conclusion
The occurrence of IDH is associated with worse outcomes in patients with AKI requiring intermittent hemodialysis. Therefore, careful monitoring and early intervention of IDH may be necessary in this patient subset.
9.Optimal use and cycling strategies of Janus kinase inhibitors in ulcerative colitis: current evidence and clinical implications from the KASID Guidelines Task Force Team
Seung Min HONG ; Dong Hyun KIM ; June Hwa BAE ; Seung Yong SHIN ; Eun Mi SONG ; Ji Eun KIM ; Young Joo YANG ; Jiyoung YOON ; Sang-Bum KANG ; Eun Soo KIM ; Seong-Eun KIM ; Seong-Jung KIM ; Jun LEE ; Soo-Young NA ; Soo Jung PARK ; Sang Hyoung PARK ; Miyoung CHOI ; Myung Ha KIM ; Won MOON ; Sung-Ae JUNG ;
Intestinal Research 2026;24(1):27-37
Janus kinase (JAK) inhibitors are an important treatment option for ulcerative colitis, providing rapid onset of action, oral administration, and efficacy even after biologic failure. The 3 approved agents—tofacitinib, filgotinib, and upadacitinib—differ in JAK isoform selectivity, leading to clinically meaningful differences in efficacy and safety. Evidence from network meta-analyses, clinical trials, and real-world studies consistently shows that upadacitinib provides the highest efficacy for induction and maintenance of remission, whereas filgotinib demonstrates the most favorable safety profile. The strong efficacy of upadacitinib and tofacitinib is particularly relevant in patients with severe disease, including acute severe ulcerative colitis, and upadacitinib maintains high efficacy regardless of prior advanced therapy exposure. JAK inhibitors also benefit extraintestinal manifestations. Although risks such as herpes zoster, serious infection, thromboembolism, and major cardiovascular events differ among agents, long-term data suggest generally acceptable safety when used appropriately. Intraclass JAK-to-JAK cycling is feasible, with about half of patients achieving steroid-free clinical remission in retrospective cohorts. Based on mechanistic, clinical, and real-world evidence, filgotinib may be a first-line option for patients with lower disease activity or when safety is a priority, whereas upadacitinib or tofacitinib may be preferred in higher disease activity. Strategically selecting agents may improve durability and outcomes.
10.Long-term bladder and renal outcomes after cutaneous vesicostomy closure in pediatric patients with non-neurogenic bladder
Kevin KANG ; Sang Woon KIM ; Ji Eun PARK ; Sang Won HAN ; Yong Seung LEE
Investigative and Clinical Urology 2026;67(1):79-87
Purpose:
To assess long-term outcomes of vesicostomy on bladder capacity (BC) and voiding function in non-neurogenic bladder, and explore the association between kidney ultrasonographic findings and renal function.
Materials and Methods:
Thirty-four patients under 2 years at the time of vesicostomy formation (2005–2020) with ≥3 years of follow-up were reviewed. Patients were further stratified based on neurogenic bladder status. Twenty-one patients were nonneurogenic. A subgroup analysis of 7 patients under 3 months with primary vesicoureteral reflux (VUR) and compromised renal function was conducted.
Results:
The median age at vesicostomy formation was 1.0 months (interquartile range [IQR] 0.0–3.5); the median duration of vesicostomy was 16.0 months (IQR 8.0–21.0). At a median age of 93.0 months (IQR 59.5–117.5), all patients achieved spontaneous micturition and continence. Eleven patients (52.4%) showed bell-shaped voiding patterns. Five patients showed interrupted (n=2) or plateau (n=3) patterns. With the exemption one patient, all patients with primary VUR showed bell-shaped curves. None initiated clean intermittent catheterization during follow-up. The median BC-to-estimated BC in patients with non-neurogenic bladder and primary VUR was 0.9 (IQR 0.7–1.1) and 0.9 (IQR 0.8–1.1), respectively. Three patients underwent revision due to prolapse. The glomerular filtration rate (GFR) was improved by 68.9% compared to the baseline (p=0.045). Parenchymal abnormalities on kidney ultrasonography were associated with decrease in GFR.
Conclusions
Vesicostomy in non-neurogenic bladder patients was associated with recovery of BC, preservation of continence, and improved renal function. Parenchymal abnormalities on ultrasonography predicted lower GFR.

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