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.

Background: s/Aims: Pancreaticoduodenectomy (PD) is the standard treatment for periampullary tumors, but it is technically challenging. Evidence directly comparing open, laparoscopic, robotic, and hybrid approaches is limited. This study conducts a network meta-analysis (NMA) to compare the perioperative and oncologic outcomes of open PD (OPD), laparoscopic PD (LPD), robotic PD (RPD), and hybrid PD. Methods: We searched PubMed, EMBASE, and the Cochrane Library for studies published between January 1994 and August 2024.We included randomized controlled trials and comparative observational studies that evaluated at least two PD approaches. Perioperative outcomes were the primary endpoints, while oncologic safety served as a secondary endpoint. A random-effects NMA was performed, establishing treatment hierarchies through ranking probabilities (PROSPERO ID: CRD420250365864). Results: A total of 78 studies were included (5 randomized and 73 retrospective). RPD was associated with lower blood loss compared to OPD (mean difference [MD], –163.85 mL) and LPD (MD, –84.14 mL). Hospital stays were also shorter for RPD compared to OPD (MD, –2.50 days) and LPD (MD, –1.88 days). In contrast, OPD was the most time-efficient approach compared to LPD (MD, –77.61 minutes) and RPD (MD, –73.30 minutes). Mortality rates, severe complications, clinically relevant postoperative pancreatic fistula rates, and reoperation rates were comparable across all surgical approaches. In terms of oncologic safety, lymph node yield and R0 resection rates were similar for all modalities. Conclusions While OPD is the most time-efficient approach, RPD provides significant advantages in reducing intraoperative blood loss and shortening hospital stays compared to both LPD and OPD.

Background: Current guidelines recommend factor IIa- or Xa-specific inhibitors over warfarin analogs for preventing thromboembolic stroke in patients with atrial fibrillation (AF).However, their plasma concentrations in Korean patients are not well understood. Methods: We conducted a single-center laboratory study to determine the distribution ranges of peak and trough concentrations of three factor Xa inhibitors (apixaban, edoxaban, and rivaroxaban) prescribed for preventing strokes in patients with AF. Patients receiving one of these drugs and undergoing blood specimen collection for laboratory tests were screened. Blood specimens were obtained from patients who had adhered to the prescribed drug regimen consistently for at least 1 week. Drug plasma concentrations were measured using heparin liquid-reagent technology-based anti-Xa chromogenic assays. Results: We selected 459 patients who were taking standard or on-label-reduced doses of apixaban (N = 252), edoxaban (N = 182), or rivaroxaban (N = 25). The 5th–95th percentile ranges of the peak concentrations were 84–414 ng/mL (apixaban), 72–424 ng/mL (edoxaban), and 97–517 ng/mL (rivaroxaban). The respective 5th–95th percentile ranges of the trough concentrations were 44–237 ng/mL, 23–93 ng/mL, and 13–219 ng/mL. Approximately 19.6% (apixaban), 33.3% (edoxaban), and 64.0% (rivaroxaban) of patients in each group had peak concentrations out of the predicted distribution ranges based on pharmacokinetic data. Approximately 7.3%, 52.8%, and 8.3% of patients had trough concentrations out of the predicted distribution ranges. Conclusions A considerable proportion of Korean patients with AF taking factor Xa inhibitors may require population-specific reference ranges to guide therapeutic monitoring.

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.

Objective: Cyclin-dependent kinase 4/6 (CDK4/6) inhibitors combined with endocrine therapy (ET) constitute the standard systemic treatment for estrogen receptor-positive, human epidermal growth factor 2-negative (ER+/HER2-) metastatic breast cancer (MBC). However, treatment responses remain heterogeneous, highlighting the need for reliable prognostic markers. This study aimed to evaluate the prognostic significance of 18F-fluorodeoxyglucose (FDG) PET/CT findings in this setting. Materials and Methods: This retrospective single-center cohort study included patients with ER+/HER2- MBC who underwent18F-FDG PET/CT before initiating CDK4/6 inhibitors plus ET between 2018 and 2023. Maximum standardized uptake value(SUVmax), whole-body metabolic tumor volume (MTV), and total lesion glycolysis (TLG) were measured. Progression-free survival (PFS) and overall survival (OS) were evaluated as the primary and secondary outcomes, respectively, using multivariable Cox models. PET parameters (SUVmax, MTV, and TLG) were analyzed as both continuous and dichotomized variables based on median values, adjusting for relevant clinical covariates. Results: Among the 374 patients, 82 (21.9%) presented with de novo metastatic disease, and 357 (95.5%) received CDK4/6 inhibitors as first-line therapy. In multivariable Cox analysis, all continuous PET parameters were independently associated with PFS (adjusted hazard ratio for SUVmax 1.05 [95% confidence interval 1.02–1.08]; log-transformed MTV 1.16 [1.08–1.25]; and log-transformed TLG 1.14 [1.07–1.23]) and OS (SUVmax 1.08 [1.04–1.11]; log-transformed MTV 1.24 [1.12–1.38]; and log-transformed TLG 1.22 [1.11–1.34]) with all P < 0.001. Results based on dichotomized PET parameters were similar to those obtained with continuous values: PFS (adjusted hazard ratio for SUVmax ≥ 7.6, 1.41 [1.08–1.85]; MTV ≥ 21.2 cm 3 , 1.41 [1.08–1.86]; and TLG ≥ 78.9, 1.51 [1.14–1.99]) with P ≤ 0.013 and OS (1.43 [1.01–2.04]; 1.84 [1.28– 2.66]; and 1.73 [1.20–2.50], respectively) with P ≤ 0.046. Conclusion Pretreatment 18F-FDG PET/CT parameters are independent prognostic markers in patients with ER+/HER2- MBC receiving CDK4/6 inhibitors with ET, supporting their potential utility in risk stratification.

Conventional aryl hydrocarbon receptor (AhR) antagonists, which play a critical role in modulating tumor immune evasion, have shown limited clinical translation due to poor solubility, restricted systemic exposure, and dose-limiting toxicities. To overcome these limitations, we developed SB5794, a phosphate prodrug of the potent AhR antagonist SB2617, designed to improve aqueous solubility and pharmacokinetic properties. SB5794 exhibited markedly enhanced solubility and achieved more than six-fold higher systemic exposure in mice compared with SB2617, while fully retaining its in vitro AhR antagonistic activity. In syngeneic tumor models, SB5794 significantly inhibited tumor growth, and its combination with anti–PD-1 therapy further enhanced antitumor efficacy. However, repeated-dose studies revealed dose-dependent histopathological changes in the gastrointestinal tract, liver, and immune organs. Collectively, these findings demonstrate that SB5794 possesses improved drug-like properties and strong immunomodulatory activity, supporting its potential as a next-generation AhR-targeted immunotherapeutic candidate.

Autoimmune hemolytic anemia (AIHA) is a rare immune-mediated disorder in children that can present as primary or secondary to other diseases. Here, we report an unusual case of steroid-refractory warm AIHA in an 11-year-old girl whose condition was ultimately cured after removal of a benign ovarian tumor. Despite receiving multiple lines of therapy—including corticosteroids, rituximab, cyclosporine, sirolimus, and mycophenolate mofetil—the patient experienced recurrent hemolysis and steroid dependence for nearly four years. Abdominopelvic imaging performed to evaluate fever revealed bilateral ovarian cystic lesions, including a left-sided dermoid cyst. Surgical resection of the tumor led to complete and sustained hematologic remission, with normalization of hemoglobin, bilirubin, and reticulocyte counts, allowing discontinuation of all immunosuppressive agents. No recurrence of hemolysis was observed during 18 months of follow-up. This case highlights the potential for benign ovarian tumors to act as a rare secondary cause of AIHA through paraneoplastic or immune cross-reactive mechanisms. Awareness of such associations is crucial when evaluating pediatric patients with refractory or relapsing AIHA, as identification and removal of an occult tumor may achieve definitive resolution of hemolysis and avoid long-term immunosuppression.

Subarachnoid hemorrhage (SAH) is a stroke subtype with high mortality and poor functional outcomes. Prompt occlusion of a ruptured aneurysm at an early stage is crucial to prevent rebleeding, which can result in even higher mortality and more severe disabilities. The most critical initial decision in SAH management is the choice of treatment method with surgical clipping or endovascular coiling. We aimed to develop an evidence-based clinical guideline to select the optimal initial treatment in patients with SAH. We developed this guideline based on evidence from systematic reviews and meta-analyses via a de novo process. A systematic literature review was conducted across four databases (MEDLINE, Embase, Cochrane, and KoreaMed) to answer two population, intervention, comparison, outcome questions comparing clipping and coiling. The risk of bias was assessed using ROB 2.0 and the Newcastle-Ottawa Scale. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses flow diagrams and meta-analyses were generated for functional outcome and mortality. We included six randomized control trials (RCTs) and 58 observational studies. Meta-analysis of RCTs showed that coiling improved functional outcomes compared to clipping (odds ratio [OR], 0.91; 95% confidence interval [CI], 0.86–0.97). No significant mortality difference was observed in RCTs (OR, 1.38; 95% CI, 0.91–2.09), but non-RCTs favored clipping for reduced mortality (OR, 0.77; 95% CI, 0.69–0.86). However, it is difficult to generalize these findings to all clinical situations, as patients with SAH have a highly variable clinical course. Final treatment decision should be tailored to the individual patient’s status, including aneurysm location, morphology, and the expertise available at the treatment center. Such decisions are best made by specialists such as a board-certified physician and should be explained to the patient and their caregivers, along with the rationale for selecting the most appropriate treatment at the given hospital. Korea has many certified endovascular neurosurgeons, cerebrovascular surgeons, and certified cerebrovascular centers. Proper selection of the most suitable treatment method by certified physicians and centers would greatly benefit patient outcomes and healthcare professionals.

Intrahepatic cholangiocarcinoma (CCA) is the second most common primary liver cancer after hepatocellular carcinoma (HCC). However, combined HCC-CCA is a rare malignancy exhibiting hepatocytic and cholangiocytic differentiation. For both tumors, R0 resection with regional lymph node dissection remains the only potentially curative treatment. Nevertheless, key aspects of surgical management remain controversial. In this narrative review, we synthesize contemporary evidence on the surgical management of intrahepatic CCA and combined HCC-CCA. We summarize current data on lymphadenectomy, safety, and oncologic comparability of minimally invasive vs. open surgery, and integration of liver hypertrophy techniques for major hepatectomy. We also review the emerging clinical experience with immune checkpoint inhibitor-based chemoimmunotherapy as a neoadjuvant treatment and conversion surgery for advanced disease. We highlight persisting knowledge gaps and propose practical perspectives to support individualized surgical planning for this heterogeneous disease.

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.