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.

Myopia, particularly high myopia, is a significant risk factor for several ocular pathologies including cataract, glaucoma, and retinal detachment. Excessive axial elongation associated with high myopia can induce biomechanical stretching, increasing the risk of serious complications like posterior staphyloma and myopic maculopathy. Global meta-analyses estimate that approximately 10 million people were visually impaired due to myopic maculopathy in 2015, with 3 million being blind. Recent nationwide surveys in South Korea revealed a prevalence of 65.4% for myopia and 6.9% for high myopia in children and adolescents, highlighting the urgent need for effective management. Delaying the onset and slowing the progression of myopia during childhood and adolescence is crucial for reducing the potential lifetime risk of these complications. This consensus statement, prepared by the Korean Myopia Society for the Korean Association for Pediatric Ophthalmology and Strabismus (KAPOS), reviews the current evidence for myopia control interventions and provides management strategies applicable to the South Korean clinical setting. Key interventions covered include lifestyle modifications (outdoor time, near work adjustment), optical methods (myopia-control spectacle lenses, dual-focus soft contact lenses, orthokeratology), and pharmacologic treatment (low-concentration atropine), as well as combination therapies. The statement also addresses patient selection, treatment outcome evaluation using spherical equivalent and axial length changes, and the crucial aspects related to treatment cessation and the rebound effect.

Purpose: Postoperative endophthalmitis is a sight-threatening intraocular infection requiring prompt treatment. This study aimed to compare the clinical outcomes of intravitreal 0.625% povidone-iodine (PI) injection with intravitreal antibiotic injection for the treatment of postoperative endophthalmitis. Methods: A retrospective review of 40 eyes diagnosed with postoperative endophthalmitis was conducted. Patients were divided into two groups: group 1 received intravitreal 0.625% PI injection (0.1 mL), while group 2 received intravitreal antibiotic injection. Clinical data, including best-corrected visual acuity (BCVA), intraocular pressure, the number of intravitreal injections, duration of anterior chamber hypopyon, and the need for pars plana vitrectomy (PPV), were analyzed. Results: Group 1 (24 eyes) showed significant improvements in BCVA posttreatment (mean, 1.04 ± 0.95 logMAR; p < 0.001) compared to group 2 (16 eyes; mean, 1.26 ± 0.99 logMAR; p = 0.092). Severe visual impairment (BCVA < 10 / 100) was significantly less frequent in group 1 (25.0%) than in group 2 (62.5%) (p = 0.025). The mean duration of hypopyon was shorter in group 1 (2.6 ± 2.2 days) compared to group 2 (6.4 ± 7.3 days, p = 0.048). Fewer intravitreal injections (p = 0.002) and PPV (p = 0.002) were required in group 1. Conclusions Intravitreal 0.625% PI injection was associated with fewer intravitreal injections, shorter hypopyon duration, and more favorable visual outcome–related measures, including significant visual improvement from baseline and a lower frequency of severe visual impairment, compared with intravitreal antibiotic treatment. These findings suggest that PI may be considered a safe and effective initial treatment option for postoperative endophthalmitis. Further prospective studies are needed to validate these results.

Purpose: Radiotherapy (RT) remains a cornerstone of curative treatment for localized and locally advanced prostate cancer. However, dose escalation to improve tumor control is often constrained by the proximity of the rectum, which increases the risk of gastrointestinal (GI) and genitourinary toxicities. Biodegradable rectal spacers inserted between the prostate and rectum have emerged as an effective approach to reduce rectal radiation exposure. This guideline provides evidence-based recommendations on indications, contraindications, procedural standards, and clinical management for biodegradable rectal spacer insertion during prostate cancer RT. Materials and Methods: This guideline was developed by a multidisciplinary expert panel through a systematic review of the literature, analysis of international guidelines (National Comprehensive Cancer Network, European Association of Urology, American Society for Radiation Oncology), and expert consensus among radiation oncologists, radiologists, and urologists with clinical experience in spacer insertion. The strength of each recommendation and the level of evidence were classified according to the modified GRADE (Grading of Recommendations, Assessment, Development, and Evaluation) system. Results: Spacer insertion is conditionally recommended (Grade C, Level I) for patients receiving definitive external-beam RT without rectal invasion. It reduces the high-dose rectal irradiation volume (V70–75) by >50%, decreases acute GI toxicity, and helps maintain bowel-related quality of life. However, the benefit for late severe toxicity (grade 2 or higher) remains debated in recent meta-analyses. Contraindications include rectal invasion, anatomical inaccessibility, infection, and material hypersensitivity. Procedures should be performed under local anesthesia in a sterile environment by trained physicians. Short-course antibiotics and simulator-based training, including completion of multiple supervised cases, are advised. Conclusion Biodegradable rectal spacer insertion is clinically validated and effective in reducing acute rectal toxicity. Although pivotal trials demonstrated a favorable procedural safety profile, real-world postmarket data include reports of rare but severe procedural complications. This guideline provides standardized recommendations tailored to Korean clinical practice while remaining consistent with international standards, emphasizing the importance of operator training and careful patient selection.

Objectives: 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. 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 5460 ESD cases from 5250 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.

Objective: To compare coronary artery dimension-adjusted subtended myocardial mass between patients with hypertrophic cardiomyopathy (HCM) and a normal population without detectable atherosclerosis, and between HCM patients with and without chest pain. Materials and Methods: Twenty-five patients with HCM but no detectable atherosclerosis on coronary computed tomography angiography (CCTA) were included in the study. This group comprised 14 patients with chest pain and 11 patients without chest pain. They were matched with 25 healthy participants based on sex, age, coronary dominance pattern, and body surface area. The minimal lumen area (MLA) and subtended myocardial volume (V sub) were assessed in the left main (LM), proximal left anterior descending (pLAD), proximal left circumflex (pLCx), and proximal right coronary (pRCA) arteries. Additionally, an index of the subtended myocardial mass adjusted for the MLA, calculated as V sub/MLA 2 , was determined. Results: MLA was significantly larger in patients with HCM compared to the control group in LM (20.93 ± 6.31 mm 2 vs.15.24 ± 3.90 mm 2 , P< 0.001), pLAD (14.28 ± 3.55 mm 2 vs. 11.36 ± 2.07 mm 2, P = 0.001), pLCx (10.94 ± 3.60 mm 2 vs. 9.15 ± 2.93 mm 2 , P = 0.045), and pRCA (13.41 ± 4.85 mm 2 vs. 11.22 ± 3.20 mm 2 , P = 0.018). Despite an increase in coronary luminal area, patients with HCM exhibited significantly higher V sub/MLA 2 compared to the control group in both the pLAD (403.56 ± 200.35 mm -1 vs. 241.70 ± 85.87 mm -1 , P < 0.001) and the pRCA (186.06 ± 95.07 mm -1 vs. 125.07 ± 70.18 mm -1 , P= 0.007). V sub/MLA 2 was significantly elevated in patients with chest pain compared to those without in the pLAD (473.75 ± 227.38 mm -1 vs. 314.24 ± 110.74 mm -1 , P = 0.018) and the pLCx (417.04 ± 182.65 mm -1 vs. 275.29 ± 112.97 mm -1 , P = 0.044). Conclusion CCTA-derived V sub/MLA 2 may more accurately reflect the balance between myocardial blood supply and demand, offering insights into the occurrence of demand angina in patients with HCM without obstructive coronary artery disease.