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.

Background/Aims: Endoscopic anti-reflux therapy is a therapeutic option for gastroesophageal reflux disease (GERD), providing durable effects. However, clinical data from Korea remain limited. This study evaluates the clinical outcomes of endoscopic radiofrequency Stretta therapy in Korean patients. Methods: A retrospective analysis was conducted on 71 patients with GERD who underwent Stretta therapy at 2 tertiary hospitals in Korea between November 2015 and July 2021. Clinical outcomes, including patient satisfaction, medication cessation or reduction, and complications, were evaluated. Pre- and post-procedural esophageal manometry and 24-hour pH monitoring test results were also analyzed. Results: Patient satisfaction rates at 1, 6, and 12 months post-procedure were 54.7% (35/64), 70.0% (28/40), and 75.0% (21/28), respectively. Medication cessation or reduction was achieved in 31.2% (20/64) at 1 month, 70.0% (28/40) at 6 months, and 67.9% (19/28) at 12 months. Esophageal manometry (n = 21) showed no significant changes in mean lower esophageal sphincter pressure (18.7 mmHg [2.5-52.9] vs 17.4 mmHg [0.0-43.0], P = 0.702) or mean integrated relaxation pressure (8.2 mmHg [0.0-28.0] vs 10.1 mmHg [0.0-31.0], P = 0.840). The 24-hour pH monitoring (n = 18) demonstrated a nonsignificant decrease in acid exposure time (pH < 4) from 2.3% (0.0-8.4) to 1.6% (0.0-7.3) (P = 0.182). Similarly, the DeMeester score decreased non-significantly from 8.4 (0.8-27.7) to 6.6 (0.8-21.8) (P = 0.352). No procedure-related complications occurred. Conclusion Endoscopic radiofrequency Stretta therapy appears to be a safe treatment option for GERD and may provide favorable patient satisfaction and medication reduction.

Background/Aims: Potassium-competitive acid blockers (P-CABs) have emerged as promising alternatives to proton pump inhibitors (PPIs) to treat erosive esophagitis (EE). This study aims to compare the efficacy and safety of P-CABs and PPIs in patients with mild to severe EE stratified by treatment phase. Methods: A systematic literature search was conducted using PubMed, MEDLINE, and the Cochrane Central Register of Controlled Trials. Randomized controlled trials comparing the efficacy of P-CABs and PPIs for EE were included. The pooled risk ratios (RRs) and risk differences with 95% confidence intervals (CIs) were calculated. A frequentist network meta-analysis was performed, and treatment ranking was assessed using P-scores. Results: Nineteen studies evaluating 5 P-CABs (vonoprazan, tegoprazan, keverprazan, fexuprazan, and zastaprazan) and 2 PPIs (lansoprazole and esomeprazole) were included. P-CABs demonstrated superior efficacy in healing EE during the initial phase, particularly in patients with severe EE (RR = 1.10; 95% CI, 1.00-1.20) and were also associated with a lower EE recurrence risk during maintenance treatment (RR = 0.59; 95% CI, 0.41-0.85). The efficacy was notably greater in patients with higher EE severity and among cytochrome P450 2C19 extensive metabolizers. The safety profiles of the P-CABs and PPIs were comparable. Vonoprazan consistently ranked the highest for both initial treatment (P-score = 0.68) and maintenance (P-score = 0.94). Conclusions P-CABs, especially vonoprazan, showed superior efficacy compared to PPIs in both the initial and maintenance treatment of EE. These findings support the use of P-CABs as a potent and reliable first-line option for EE management, particularly in high-risk populations, with acceptable safety outcomes.

Gastroesophageal reflux disease (GERD) is a chronic and relapsing gastrointestinal disorder characterized by the reflux of gastric contents into the esophagus, leading to troublesome symptoms and/or complications. Since the publication of the 2020 Seoul Consensus on GERD, significant new evidence has emerged, particularly regarding acid-suppressive therapies and diagnostic approaches. This 2025 focused update aims to refine GERD management strategies by incorporating the latest evidence on acid suppressive therapies and regional considerations in Asian populations. This study builds on the 2020 Seoul Consensus by integrating systematic reviews, meta-analyses, and expert consensuses to offer updated recommendations for the definition and medical treatment of GERD. These guidelines incorporate recent advances in acid-suppressive therapies, particularly potassium-competitive acid blockers, and adopt updated diagnostic frameworks in accordance with the Lyon Consensus 2.0. Key clinical questions were identified and structured using the following format: Population, Intervention, Comparator, Outcome. The resulting recommendations address the initial treatment, long-term maintenance strategies, and role of personalized therapy based on disease severity, such as the grade of reflux esophagitis. Six key statements are presented: updated definition and classification of GERD (Statement 1); initial and long-term treatment strategies tailored to GERD phenotypes, such as non-erosive reflux disease, mild erosive esophagitis, and severe erosive esophagitis (Statements 2-5); and dose optimization strategies for long-term safety (Statement 6). These guidelines aim to support gastroenterologists and general healthcare providers in making individualized evidence-based decisions for GERD management.

Purpose: Alectinib has been approved for anaplastic lymphoma kinase (ALK)–positive non–small cell lung cancer (NSCLC) at 300 mg twice daily in Japan, lower than global standard of 600 mg twice daily. This study evaluated the clinical relevance of the reduced dose by comparing outcomes between the two doses. Materials and Methods: This study included patients with advanced ALK-positive NSCLC who received alectinib at Samsung Medical Center, Korea. The progression-free survival (PFS), overall survival, cumulative incidence of central nervous system (CNS) progression, and safety profiles were retrospectively reviewed and compared. Results: Among 306 patients, 32 and 274 received alectinib at either 300 or 600 mg twice daily, respectively. The 300 mg group showed a slight but not significant advantage in PFS (hazard ratio [HR], 0.82; 95% confidence interval [CI], 0.44 to 1.51; p=0.51) and overall survival (HR, 0.51; 95% CI, 0.20 to 1.21; p=0.13). Superior outcome with 300 mg was remarkable in patients with lower body weight (≤ 60 kg), but diminished in patients with higher body weights. Patients with baseline brain metastasis in the 300 mg group exhibited a slight increase in incidence of CNS failure (HR, 1.76; 95% CI, 0.53 to 5.8; p=0.36). Although the safety profiles were mostly mild, adverse events were more frequent in the 600 mg group, 50% of which requiring dose reduction. Conclusion Alectinib at 300 mg twice daily seems an acceptable dose in East Asians with ALK-positive NSCLC. Notably, our data favor 300 mg twice daily in patients with lower body weight and no baseline brain metastasis, considering the more tolerable safety profiles and the potential to reduce medical costs.

Purpose: The aim of this study is to compare the detection ability of quality of life (QoL) changes and responsiveness of the KOrean QUality of life in Stomach cancer patients Study group (KOQUSS)-40 and European Organization for Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ). Materials and Methods: A multicenter prospective observational study was conducted to evaluate QoL changes after various gastrectomies between January 2021 and April 2022. Participants were instructed to complete the KOQUSS-40 and EORTC QLQ-C30/STO22 preoperatively and at 1, 3, 6, and 12 months postoperatively. QoL changes over time and QoL responsiveness were assessed for each questionnaire. Results: Data from 491 patients who underwent curative gastrectomy for gastric cancer at 22 institutions were analyzed. The summary scores of the KOQUSS-40 and EORTC QLQ-STO22 showed significant differences between the total and proximal gastrectomy groups (p=0.044 and p=0.038, respectively), but no difference was observed for the EORTC QLQ-C30. Dysphagia on the KOQUSS-40 was significantly different between the total and proximal gastrectomy groups (p=0.031); however, dysphagia on the EORTC QLQ-STO22 did not differ. The responsiveness of the KOQUSS-40 was similar to that of the EORTC QLQ in patients who experienced ≥ 10% body weight loss, but approximately 10% less in patients receiving adjuvant chemotherapy than the EORTC QLQ. Conclusion KOQUSS-40 has several advantages over EORTC QLQ-C30/STO22 when comparing QoL between the total and proximal gastrectomy groups. The findings provide information for researchers investigating the QoL of patients who have undergone curative gastrectomy for gastric cancer.

Purpose: This study aimed to assess the efficacy and safety of first-line modified FOLFIRINOX in patients with advanced urachal cancer. Materials and Methods: The ULTIMA trial (NCT04611724) is a single-arm, open-label, multicenter phase II study evaluating modified FOLFIRINOX (oxaliplatin 85 mg/m2 over 2 hours, irinotecan 150 mg/m2 over 1.5 hours, leucovorin 400 mg/m2 over 2 hours, and 5-fluorouracil 2,400 mg/m2 over 46 hours) plus prophylactic pegteograstim in patients with recurrent or metastatic urachal cancer every 2 weeks for up to 12 cycles, or until disease progression or unacceptable toxicity. The primary endpoint was the overall response rate (ORR). Secondary endpoints included progression-free survival (PFS), overall survival (OS), and the incidence of febrile neutropenia. Results: Between April 2021 and November 2023, 21 patients with advanced urachal cancer were enrolled across five cancer centers. The median age was 50 years (range, 28 to 68 years), with 15 male patients. The most common metastatic site was the lung (47.6%), followed by lymph nodes (38.1%) and peritoneal seeding (33.3%). Two patients and 11 patients achieved a complete and partial response, respectively, yielding an ORR of 61.9%. The study met its primary endpoint in the first stage. With a median follow-up of 23.3 months, the median PFS was 9.3 months (95% confidence interval [CI], 6.7 to 11.9), and the median OS was 19.7 months (95% CI, 14.3 to 25.1). The treatment regimen was well tolerated, with no unexpected adverse events, and no instances of febrile neutropenia or grade 4 adverse events. Conclusion In this preliminary analysis of the ULTIMA trial, Modified FOLFIRINOX demonstrated a promising ORR and PFS in patients with advanced urachal cancer. Completing the full study is essential to confirm the potential role of this regimen in the management of advanced urachal cancer.

Purpose: Accumulating evidence has clarified that gut dysbiosis is involved in lung cancer development and progression. Although the relationship between tumors and gut microbiota has been extensively studied using clinical samples, no studies have examined the association between mutant epidermal growth factor receptor (EGFR)–induced lung carcinogenesis and dysbiosis in gut microbiota. Therefore, we investigated the gut microbiota profiles in stool samples from human lung-specific conditional EGFR-mutant transgenic mice during lung tumor carcinogenesis. Materials and Methods: Stool samples were collected before tamoxifen treatment (V1) and at each time point following mutant EGFR expression in lung tissue (V2) and lung tumor appearance (V3). Fecal 16S rRNA taxonomy was analyzed to assess microbial diversity, composition, and dynamic changes at each time point. Results: We found that microbiota richness and diversity were significantly elevated when tumors developed and grew in the lung. Phylogenetic analysis of the microbial community revealed that Lachnospiraceae, Ruminococcaceae, Porphyromonadaceae, Rhodospirillaceae, Odoribacteraceae, and Desulfovibrionaceae showed a significant increase at the V3 stage compared to the V1 stage at the family level. In contrast, Lactobacillaceae, Bacteroidaceae, Muribaculaceae, Coriobacteriaceae, and Rikenellaceae significantly decreased at the V3 stage compared to the V1 stage. Furthermore, Lactobacillus species, also known as short chain fatty acid-producing bacteria, were relatively abundant at the V1 stage but were depleted with the occurrence of lung tumors at the V3 stage. Conclusion Changes in gut microbiota, such as Lactobacillus species, may be a predictive factor for the emergence and progression of tumors in an animal model of lung adenocarcinoma induced by mutant EGFR.

Purpose: This study aimed to explore the practices, perceptions, and barriers related to specialty palliative care (SPC) referrals among oncologists in Korea, highlighting the clinical implications of early integration. Materials and Methods: A cross-sectional online survey targeting board-certified hemato-oncology specialists was conducted between August 1-25, 2024. The survey assessed referral practices, attitudes toward early SPC integration, referral criteria, barriers, and institutional characteristics. Results: A total of 227 oncologists participated (response rate, 36.7%). Among them, 68.7% reported frequent SPC referrals, with higher referral rates observed among younger physicians, those in tertiary hospitals, and institutions with in-house SPC teams (p < 0.001). Although 74.9% supported early SPC integration, referrals were often inconsistently timed, frequently occurring after disease progression or at the discontinuation of chemotherapy. For time-based referrals, the most commonly endorsed triggers were disease progression despite palliative second-line treatment and a prognosis of expected mortality within 6-12 months. Need-based referral triggers such as patient or family requests (96.5%), psychological distress (89.9%), or uncontrolled symptoms (83.3%), were also widely endorsed. The major barriers to early SPC integration included patient and family resistance (70.0%) and limited availability of SPC teams (34.4%). Conclusion This study emphasizes the importance of systematic efforts to promote timely SPC integration in Korea, including education to raise patient awareness, improved referral systems, and enhanced infrastructure. The positive attitudes toward early SPC among oncologists reflect a growing recognition of its value, highlighting the need for strategies that align with international standards.