Purpose: Incidence of T1 colorectal cancer (CRC) has steadily increased. Although endoscopic resection is curative for many patients, lymph node metastasis (LNM) remains problematic, often prompting additional colectomy after endoscopic therapy. This study aimed to comparatively analyze major international guidelines for post-resection management of T1 CRC, summarize evidence supporting the key pathological risk factors for LNM, and examine the effect of divergent definitions and thresholds on variations in clinical decision-making. Methods: Within North America, Europe, and East Asia, current and comprehensive guidelines issued by internationally recognized professional societies for CRC management were included in the analysis. Each guideline was reviewed for its issuing organization, target population, scope, evidence methodology, consensus process, and update frequency. Our evaluation assessed how each guideline addressed individual pathological risk factors associated with LNM, specifically focusing on five key shared features. Results: Five pathological features were consistently recognized as increasing LNM risk:lymphovascular invasion, poor histological differentiation, deep submucosal invasion, tumor budding, and positive or indeterminate resection margins. Overall, although the guidelines shared the core pathological risk factors, their relative weights differed. Eastern guidelines were found to favor surgery based on a single adverse feature, whereas Western approaches prioritize cumulative risk and patient-specific factors. Conclusion By highlighting areas of consensus and controversy, this comparative analysis underscores the limitations of binary risk stratification and the resulting burden of overtreatment; it also discusses emerging strategies to support more precise, individualized management of T1 CRC.

Purpose: To develop the 2025 update to the Korean colorectal cancer (CRC) screening guidelines by systematically evaluating recent evidence, integrating domestic data, and addressing changes since the 2015 guideline revision, thereby providing an evidence-based standard for clinicians and policymakers. Methods: A multidisciplinary committee developed the guidelines using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) methodology. The process included formulation of three key questions addressing screening efficacy, diagnostic accuracy, and optimal screening age and interval. A systematic review of international guidelines and primary literature was conducted, yielding 327 eligible studies. In addition, a utility-based analysis using a Markov model was performed to determine optimal screening ages and intervals. Results: The evidence synthesis identified high-certainty evidence supporting the use of the fecal immunochemical test (FIT) for reducing CRC mortality and moderate-certainty evidence for colonoscopy. Evidence for computed tomographic colonography (CTC) and stool DNA testing was rated as very low certainty. Based on the evidence review and cost-utility analysis, the committee conditionally recommends CRC screening for asymptomatic, average-risk adults aged 45–74 years using either colonoscopy every 10 years or FIT every 1–2 years. CTC and stool DNA testing were not recommended owing to insufficient evidence. Conclusion The 2025 Korean Guidelines for Colorectal Cancer Screening present updated, evidence-based recommendations tailored to the domestic healthcare context. By conditionally endorsing both colonoscopy and FIT for individuals aged 45–74 years, these guidelines aim to improve population-level screening effectiveness and reduce the burden of CRC in South Korea.

Flexible gastrointestinal (GI) endoscopy is a fundamental skill in surgical practice, offering both diagnostic and therapeutic capabilities for a wide range of GI diseases. In Korea, the incidence estimates for gastric and colorectal cancers rank among the highest worldwide, underscoring the critical need for well-trained endoscopists. Surgeons play a pivotal role in managing GI diseases, reinforcing the necessity of systematic and comprehensive endoscopic education.This paper reviews the status of surgical endoscopy education in Korea, focusing on its historical evolution, structured training programs for residents and fellows, certification processes, and continuing medical education initiatives. Despite significant advancements led by organizations such as the Korean Surgical Society, challenges persist, including disparities in training opportunities across institutions and limited access to advanced therapeutic endoscopy. To address these issues, strategic recommendations include standardizing educational curricula, optimizing residency workloads for dedicated endoscopy training, enhancing simulation-based education through high-fidelity simulators and artificial intelligence, and fostering international collaboration to encourage global best practices.Implementing these strategies will strengthen Korea’s GI endoscopy education system,ensuring that future surgeons are well-prepared to meet the evolving demands of patient care.

Flexible gastrointestinal (GI) endoscopy is a fundamental skill in surgical practice, offering both diagnostic and therapeutic capabilities for a wide range of GI diseases. In Korea, the incidence estimates for gastric and colorectal cancers rank among the highest worldwide, underscoring the critical need for well-trained endoscopists. Surgeons play a pivotal role in managing GI diseases, reinforcing the necessity of systematic and comprehensive endoscopic education.This paper reviews the status of surgical endoscopy education in Korea, focusing on its historical evolution, structured training programs for residents and fellows, certification processes, and continuing medical education initiatives. Despite significant advancements led by organizations such as the Korean Surgical Society, challenges persist, including disparities in training opportunities across institutions and limited access to advanced therapeutic endoscopy. To address these issues, strategic recommendations include standardizing educational curricula, optimizing residency workloads for dedicated endoscopy training, enhancing simulation-based education through high-fidelity simulators and artificial intelligence, and fostering international collaboration to encourage global best practices.Implementing these strategies will strengthen Korea’s GI endoscopy education system,ensuring that future surgeons are well-prepared to meet the evolving demands of patient care.

Flexible gastrointestinal (GI) endoscopy is a fundamental skill in surgical practice, offering both diagnostic and therapeutic capabilities for a wide range of GI diseases. In Korea, the incidence estimates for gastric and colorectal cancers rank among the highest worldwide, underscoring the critical need for well-trained endoscopists. Surgeons play a pivotal role in managing GI diseases, reinforcing the necessity of systematic and comprehensive endoscopic education.This paper reviews the status of surgical endoscopy education in Korea, focusing on its historical evolution, structured training programs for residents and fellows, certification processes, and continuing medical education initiatives. Despite significant advancements led by organizations such as the Korean Surgical Society, challenges persist, including disparities in training opportunities across institutions and limited access to advanced therapeutic endoscopy. To address these issues, strategic recommendations include standardizing educational curricula, optimizing residency workloads for dedicated endoscopy training, enhancing simulation-based education through high-fidelity simulators and artificial intelligence, and fostering international collaboration to encourage global best practices.Implementing these strategies will strengthen Korea’s GI endoscopy education system,ensuring that future surgeons are well-prepared to meet the evolving demands of patient care.

Purpose: This study introduced adenomas per polypectomy (APP) as a novel metric for evaluating the progression of lesion discrimination skills among colonoscopy trainees. Methods: This retrospective study was conducted at the National Cancer Center, Korea between March 2020 and February 2023. Nine colorectal surgeons who completed a structured 1-year colonoscopy training program were included, and their performance was compared with that of 5 expert endoscopists. APP was defined as the number of histologically confirmed adenomas among the total number of polypectomies performed. The APPs were calculated serially to assess changes from the beginning to the end of the training. Results: A total of 8,072 colonoscopies were performed by 9 trainees and 11,687 by 5 experts. The average APP of the 9 trainees was 67.0%, which was significantly different from the 73.9% APP of the experts (P < 0.001). The APP progression of trainees exhibited 3 phases: phase 1 (<200 cases) showed increasing polyp detection and APP; phase 2 (200–500 cases) displayed a sharp rise in the number of polypectomies but a decline in APP; and phase 3 (>500 cases) demonstrated a decrease in the number of polypectomies with a moderate rise in APP. However, even in phase 3, the trainees’ APP remained significantly lower than that of the experts (69.9% vs. 73.9%, P = 0.027). Conclusion APP, a measure of visual adenoma discrimination ability, undergoes 3 stages of progression during colonoscopy training. This progression suggests that the APP may serve as an additional metric for assessing the effectiveness of colonoscopy training.

Background: and Purpose The accurate prediction of functional outcomes in patients with acute ischemic stroke (AIS) is crucial for informed clinical decision-making and optimal resource utilization. As such, this study aimed to construct an ensemble deep learning model that integrates multimodal imaging and clinical data to predict the 90-day functional outcomes after AIS. Methods: We used data from the Korean Stroke Neuroimaging Initiative database, a prospective multicenter stroke registry to construct an ensemble model integrated individual 3D convolutional neural networks for diffusion-weighted imaging and fluid-attenuated inversion recovery (FLAIR), along with a deep neural network for clinical data, to predict 90-day functional independence after AIS using a modified Rankin Scale (mRS) of 3–6. To evaluate the performance of the ensemble model, we compared the area under the curve (AUC) of the proposed method with that of individual models trained on each modality to identify patients with AIS with an mRS score of 3–6. Results: Of the 2,606 patients with AIS, 993 (38.1%) achieved an mRS score of 3–6 at 90 days post-stroke. Our model achieved AUC values of 0.830 (standard cross-validation [CV]) and 0.779 (time-based CV), which significantly outperformed the other models relying on single modalities: b-value of 1,000 s/mm2 (P<0.001), apparent diffusion coefficient map (P<0.001), FLAIR (P<0.001), and clinical data (P=0.004). Conclusion The integration of multimodal imaging and clinical data resulted in superior prediction of the 90-day functional outcomes in AIS patients compared to the use of a single data modality.

Purpose: To analyze adenoma detection rate (ADR) and related quality indicators of colonoscopy among trainees and make recommendations for appropriate colonoscopy training. Methods: ADR and related indicators of colonoscopies performed by 3 trainees and 5 colonoscopy experts between March and November 2022 were analyzed. These indicators were analyzed in both the entire patients and the screening/surveillance group. In addition, the training period of the 3 trainees was divided into 3 sections, and the changes in these indicators were examined. Results: The mean ADR of the 3 trainees was 50.6%. In the screening/surveillance group, the mean ADR of the 3 trainees was 51.8%, showing no significant difference from the experts' ADR (53.4%). When the training period was divided into 3 sections and analyzed in the screening/surveillance group, the mean ADR of the trainees gradually increased to 49.4%, 52.6%, and 53.6%, respectively; however, the difference was insignificant. Analyzing each trainee’s ADR, there was a significant difference among the 3 trainees (58.5% vs. 44.7% vs. 50.2%, P=0.008). However, in the third section of the training period, the 3 trainees’ ADRs were 53.0%, 49.2%, and 57.3%, respectively, showing no significant difference (P=0.606). Conclusion In the early stages of training, the ADR was higher than recommended; however, there were variances in ADR between individuals. As the training period passed, the ADR became similar at the expert level, whereas the difference in ADR between trainees decreased. Therefore, efforts to increase ADR should be made actively from the beginning of training and continued during the training period.

Purpose: To analyze adenoma detection rate (ADR) and related quality indicators of colonoscopy among trainees and make recommendations for appropriate colonoscopy training. Methods: ADR and related indicators of colonoscopies performed by 3 trainees and 5 colonoscopy experts between March and November 2022 were analyzed. These indicators were analyzed in both the entire patients and the screening/surveillance group. In addition, the training period of the 3 trainees was divided into 3 sections, and the changes in these indicators were examined. Results: The mean ADR of the 3 trainees was 50.6%. In the screening/surveillance group, the mean ADR of the 3 trainees was 51.8%, showing no significant difference from the experts' ADR (53.4%). When the training period was divided into 3 sections and analyzed in the screening/surveillance group, the mean ADR of the trainees gradually increased to 49.4%, 52.6%, and 53.6%, respectively; however, the difference was insignificant. Analyzing each trainee’s ADR, there was a significant difference among the 3 trainees (58.5% vs. 44.7% vs. 50.2%, P=0.008). However, in the third section of the training period, the 3 trainees’ ADRs were 53.0%, 49.2%, and 57.3%, respectively, showing no significant difference (P=0.606). Conclusion In the early stages of training, the ADR was higher than recommended; however, there were variances in ADR between individuals. As the training period passed, the ADR became similar at the expert level, whereas the difference in ADR between trainees decreased. Therefore, efforts to increase ADR should be made actively from the beginning of training and continued during the training period.

Purpose: To analyze adenoma detection rate (ADR) and related quality indicators of colonoscopy among trainees and make recommendations for appropriate colonoscopy training. Methods: ADR and related indicators of colonoscopies performed by 3 trainees and 5 colonoscopy experts between March and November 2022 were analyzed. These indicators were analyzed in both the entire patients and the screening/surveillance group. In addition, the training period of the 3 trainees was divided into 3 sections, and the changes in these indicators were examined. Results: The mean ADR of the 3 trainees was 50.6%. In the screening/surveillance group, the mean ADR of the 3 trainees was 51.8%, showing no significant difference from the experts' ADR (53.4%). When the training period was divided into 3 sections and analyzed in the screening/surveillance group, the mean ADR of the trainees gradually increased to 49.4%, 52.6%, and 53.6%, respectively; however, the difference was insignificant. Analyzing each trainee’s ADR, there was a significant difference among the 3 trainees (58.5% vs. 44.7% vs. 50.2%, P=0.008). However, in the third section of the training period, the 3 trainees’ ADRs were 53.0%, 49.2%, and 57.3%, respectively, showing no significant difference (P=0.606). Conclusion In the early stages of training, the ADR was higher than recommended; however, there were variances in ADR between individuals. As the training period passed, the ADR became similar at the expert level, whereas the difference in ADR between trainees decreased. Therefore, efforts to increase ADR should be made actively from the beginning of training and continued during the training period.