Colorectal cancer is the third most common cancer in Korea and the third leading cause of death from cancer. Treatment outcomes for colon cancer are steadily improving due to national health screening programs with advances in diagnostic methods, surgical techniques, and therapeutic agents.. The Korea Colon Cancer Multidisciplinary (KCCM) Committee intends to provide professionals who treat colon cancer with the most up-to-date, evidence-based practice guidelines to improve outcomes and help them make decisions that reflect their patients’ values and preferences. These guidelines have been established by consensus reached by the KCCM Guideline Committee based on a systematic literature review and evidence synthesis and by considering the national health insurance system in real clinical practice settings. Each recommendation is presented with a recommendation strength and level of evidence based on the consensus of the committee.

Background: Brugada syndrome (BrS) and arrhythmogenic cardiomyopathy (ACM) are inherited cardiac diseases that may predispose to ventricular arrhythmia. Although overlapping features between BrS and ACM have been demonstrated previously, it remains to be determined whether genetic testing for ACM-related genes is needed in BrS probands.MethodBased on a single-center, retrospective registry of BrS, we aimed to verify genetic profiles of BrS using a next-generation sequencing panel, and further analyzed genetic testing of ACM-related variants in Brugada phenotypes. Results: Among a total of 119 Brugada phenotypes, 114 patients (95.8%) were male and the mean age of onset was 43.6 years. Genetic variants were identified in 25 of the 42 patients who underwent genetic testing. Fifteen patients had BrS-related genotypes, including SCN5A in 6 patients, and non-SCN5A genes in 9 patients (SCN10A, HCN4, SCN3B, and KCNE3). Nineteen patients underwent additional genetic testing with cardiomyopathy panel, which revealed ACM-related genotypes (2 PKP2, 1 DSG2, 1 TMEM43, 1 JUP, and 1 DSP) present in 6 patients (31.5%). None of the patients had structural or electrocardiographic features that fulfilled the diagnostic criteria for ACM. Conclusions In clinical setting, ACM-related genes were identified in a significant proportion of Brugada phenotypes, supporting the argument that genetic testing of ACM overlapping is needed. Follow-up imaging studies should be considered to monitor if the disease progresses to ACM.

Background: Despite the proven effectiveness of oral antivirals against severe acute respiratory syndrome coronavirus 2 in randomized trials, their clinical reevaluation is vital in the context of widespread immunity and milder prevalent variants. This study aimed to assess the effectiveness of oral antivirals for coronavirus disease 2019 (COVID-19). Methods: This retrospective cohort study utilized a target trial emulation framework to analyze patients with COVID-19 aged 60+ from January to December 2022. Data were obtained from the Korea Disease Control and Prevention Agency and Health Insurance Review and Assessment Service. The study involved 957,036 patients treated with nirmatrelvir/ritonavir and 243,360 treated with molnupiravir, each compared with the matched control groups. Primary outcome was progression to critical COVID-19 requiring advanced respiratory support. Secondary outcomes included progression to severe COVID-19, need for supplemental oxygen, and death within 30 days of the onset of COVID-19.Number needed to treat (NNT) derived from the absolute risk reduction. Results: Nirmatrelvir/ritonavir was significantly associated with a reduced risk of severe (adjusted odds ratio [aOR], 0.823; 95% confidence interval [CI], 0.803–0.843), critical (aOR, 0.560; 95% CI, 0.503–0.624), and fatal COVID-19 (aOR, 0.694; 95% CI, 0.647–0.744).Similarly, molnupiravir reduced the risk of severe (aOR, 0.895; 95% CI, 0.856–0.937), critical (aOR, 0.672; 95% CI, 0.559–0.807), and fatal cases (aOR, 0.679; 95% CI, 0.592–0.779).NNTs for nirmatrelvir/ritonavir were 203.71 (severe), 1,230.12 (critical), and 691.50 (death);for molnupiravir, they were 352.70 (severe), 1,398.62 (critical), and 862.98 (death). Higher effectiveness was associated with older adults, unvaccinated individuals, and the late pandemic phase. Conclusion Nirmatrelvir/ritonavir and molnupiravir are effective in preventing progression to severe disease in elderly adults with COVID-19.

Background: Bladder cancer is characterized by frequent mutations, which provide potential therapeutic targets for most patients. The effectiveness of emerging personalized therapies depends on an accurate molecular diagnosis, for which the accurate estimation of the neoplastic cell percentage (NCP) is a crucial initial step. However, the established method for determining the NCP, manual counting by a pathologist, is time-consuming and not easily executable. Methods: To address this, artificial intelligence (AI) models were developed to estimate the NCP using nine convolutional neural networks and the scanned images of 39 cases of urinary tract cancer. The performance of the AI models was compared to that of six pathologists for 119 cases in the validation cohort. The ground truth value was obtained through multiplexed immunofluorescence. The AI model was then applied to 41 cases in the application cohort that underwent next-generation sequencing testing, and its impact on the copy number variation (CNV) was analyzed. Results: Each AI model demonstrated high reliability, with intraclass correlation coefficients (ICCs) ranging from 0.82 to 0.88. These values were comparable or better to those of pathologists, whose ICCs ranged from 0.78 to 0.91 in urothelial carcinoma cases, both with and without divergent differentiation/ subtypes. After applying AI-driven NCP, 190 CNV (24.2%) were reclassified with 66 (8.4%) and 78 (9.9%) moved to amplification and loss, respectively, from neutral/minor CNV. The neutral/minor CNV proportion decreased by 6%. Conclusions These results suggest that AI models could assist human pathologists in repetitive and cumbersome NCP calculations.

Purpose: Frequent neutropenia hinders uninterrupted palbociclib treatment in patients with hormone receptor (HR)–positive breast cancer. We compared the efficacy outcomes in multicenter cohorts of patients with metastatic breast cancer (mBC) receiving palbociclib following conventional dose modification or limited modified schemes for afebrile grade 3 neutropenia. Materials and Methods: Patients with HR-positive, human epidermal growth factor receptor 2–negative mBC (n=434) receiving palbociclib with letrozole as first-line therapy were analyzed and classified based on neutropenia grade and afebrile grade 3 neutropenia management as follows: group 1 (maintained palbociclib dose, limited scheme), group 2 (dose delay or reduction, conventional scheme), group 3 (no afebrile grade 3 neutropenia event), and group 4 (grade 4 neutropenia event). The primary and secondary endpoints were progression-free survival (PFS) between groups 1 and 2 and PFS, overall survival, and safety profiles among all groups. Results: During follow-up (median 23.7 months), group 1 (2-year PFS, 67.9%) showed significantly longer PFS than did group 2 (2-year PFS, 55.3%; p=0.036), maintained across all subgroups, and upon adjustment of the factors. Febrile neutropenia occurred in one and two patients of group 1 and group 2, respectively, without mortality. Conclusion Limited dose modification for palbociclib-related grade 3 neutropenia may lead to longer PFS, without increasing toxicity, than the conventional dose scheme.

Background: Peripheral blood mononuclear cells (PBMCs) are commonly used to assess in vitro immune responses. However, PBMC isolation is a time-consuming procedure, introduces technical variability, and requires a relatively large volume of blood. By contrast, whole blood assay (WBA) is faster, cheaper, maintains more physiological conditions, and requires less sample volume, laboratory training, and equipment. Objectives: Herein, this study aimed to develop a porcine WBA for in vitro evaluation of immune responses. Methods: Heparinized whole blood (WB) was diluted (non-diluted, 1/2, 1/8, and 1/16) in RPMI-1640 media, followed by phorbol myristate acetate and ionomycin. After 24 h, cells were stained for interferon (IFN)-γ secreting T-cells followed by flow cytometry, and the supernatant was analyzed for tumor necrosis factor (TNF)-α. In addition, diluted WB was stimulated by lipopolysaccharide (LPS) and polyinosinic:polycytidylic acid (poly I:C), reference strain KCTC3557 (RS), field isolate (FI), of heat-killed (HK) Streptococcus suis, and porcine reproductive and respiratory syndrome virus (PRRSV). Results: The frequency of IFN-γ + CD3 + T-cells and concentration of TNF-α in the supernatant of WB increased with increasing dilution factor and were optimal at 1/8. WB TNF-α and interleukin (IL)-10 cytokine levels increased significantly following stimulation with LPS or poly I:C. Further, FI and RS induced IL-10 production in WB. Additionally, PRRSV strains increased the frequency of IFN-γ + CD4 - CD8 + cells, and IFN-γ was non-significantly induced in the supernatant of re-stimulated samples. Conclusions We propose that the WBA is a rapid, reliable, and simple method to evaluate immune responses and WB should be diluted to trigger immune cells.

Background and Objectives: Inherited arrhythmia (IA) is a more common cause of sudden cardiac death in Asian population, but little is known about the genetic background of Asian IA probands. We aimed to investigate the clinical characteristics and analyze the genetic underpinnings of IA in a Korean cohort. Methods: This study was conducted in a multicenter cohort of the Korean IA Registry from 2014 to 2017. Genetic testing was performed using a next-generation sequencing panel including 174 causative genes of cardiovascular disease. Results: Among the 265 IA probands, idiopathic ventricular fibrillation (IVF) and Brugada Syndrome (BrS) was the most prevalent diseases (96 and 95 cases respectively), followed by long QT syndrome (LQTS, n=54). Two-hundred-sixteen probands underwent genetic testing, and 69 probands (31.9%) were detected with genetic variant, with yield of pathogenic or likely pathogenic variant as 6.4%. Left ventricular ejection fraction was significantly lower in genotype positive probands (54.7±11.3 vs. 59.3±9.2%, p=0.005). IVF probands showed highest yield of positive genotype (54.0%), followed by LQTS (23.8%), and BrS (19.5%). Conclusions There were significant differences in clinical characteristics and genetic yields among BrS, LQTS, and IVF. Genetic testing did not provide better yield for BrS and LQTS. On the other hand, in IVF, genetic testing using multiple gene panel might enable the molecular diagnosis of concealed genotype, which may alter future clinical diagnosis and management strategies.

Background: and Purpose Various mechanisms are involved in the etiology of stroke caused by atherosclerosis of the middle cerebral artery (MCA). Here, we compared differences in plaque nature and hemodynamic parameters according to stroke mechanism in patients with MCA atherosclerosis. Methods: Consecutive patients with asymptomatic and symptomatic MCA atherosclerosis (≥50% stenosis) were enrolled. MCA plaque characteristics (location and plaque enhancement) and wall shear stress (WSS) were measured using high-resolution vessel wall and four-dimensional flow magnetic resonance imaging, respectively, at five points (initial, upstream, minimal lumen, downstream, and terminal). These parameters were compared between patients with asymptomatic and symptomatic MCA atherosclerosis with infarctions of different mechanisms (artery-to-artery embolism vs. local branch occlusion). Results: In total, 110 patients (46 asymptomatic, 32 artery-to-artery embolisms, and 32 local branch occlusions) were investigated. Plaques were evenly distributed in the MCA of patients with asymptomatic MCA atherosclerosis, more commonly observed in the distal MCA of patients with artery-to-artery embolism, and in the middle MCA of patients with local branch occlusion. Maximum WSS and plaque enhancement were more prominent in the minimum lumen area of patients with asymptomatic MCA atherosclerosis or those with local branch occlusion, and were more prominent in the upstream area in those with artery-to-artery embolism. The elevated variability in the maximum WSS was related to stroke caused by artery-to-artery embolism. Conclusion Stroke caused by artery-to-artery embolism was related to plaque enhancement and the highest maximum WSS at the upstream point of the plaque, and was associated with elevated variability of maximum WSS.

Background/aims: Circulating tumor cells (CTCs) with cancer stemness have been demonstrated to be a direct cause of tumor recurrence, and only few studies have reported the role of CTCs in liver transplantation (LT) for hepatocellular carcinoma (HCC). Methods: Epithelial cell adhesion molecule+ (EpCAM+), cluster of differentiation 90+ (CD90+) and EpCAM+/CD90+ CTCs were sorted via fluorescence-activated cell sorting, and transcripts level of EpCAM, K19 and CD90 in the peripheral blood were analyzed via real-time polymerase chain reaction preoperatively and on postoperative days 1 and 7 in 25 patients who underwent living donor liver transplantation (LDLT) for HCC. EpCAM protein was assessed in HCC tissue using immunohistochemical staining. The median follow-up duration was 40 months. Results: HCC after LDLT recurred in four out of 25 patients. Detection of EpCAM+ or CD90+ CTCs correlated well with their messenger RNA levels (p<0.05). EpCAM+ CTCs were readily detected in HCC tissue expressing EpCAM protein. The detection of EpCAM+ CTCs or EpCAM+/CD90+ CTCs before surgery and on postoperative day 1 was significantly associated with HCC recurrence after LT (all p<0.05). Pretransplant serum PIVKA-II >100 mAU/mL and postoperative day 1 EpCAM+/CD90+ CTCs were independent risk factors for HCC recurrence (hazard ratio, 14.64; 95% confidence interval, 1.08 to 198.20; p=0.043 and hazard ratio, 26.88; 95% confidence interval, 1.86 to 387.51; p=0.016, respectively). Conclusions EpCAM+/CD90+ CTCs can be used preoperatively and 1 day after LDLT as key biological markers in LT candidate selection and post-LDLT management.

Objective: To propose standardized MRI-proton density fat fraction (PDFF) cutoff values for diagnosing hepatic steatosis, evaluated using contemporary PDFF measuring methods in a large population of healthy adults, using histologic fat fraction (HFF) as the reference standard. Materials and Methods: A retrospective search of electronic medical records between 2015 and 2018 identified 1063 adult donor candidates for liver transplantation who had undergone liver MRI and liver biopsy within a 7-day interval. Patients with a history of liver disease or significant alcohol consumption were excluded. Chemical shift imaging-based MRI (CS-MRI) PDFF and high-speed T2-corrected multi-echo MR spectroscopy (HISTO-MRS) PDFF data were obtained. By temporal splitting, the total population was divided into development and validation sets. Receiver operating characteristic (ROC) analysis was performed to evaluate the diagnostic performance of the MRI-PDFF method. Two cutoff values with sensitivity > 90% and specificity > 90% were selected to rule-out and rule-in, respectively, hepatic steatosis with reference to HFF ≥ 5% in the development set. The diagnostic performance was assessed using the validation set. Results: Of 921 final participants (624 male; mean age ± standard deviation, 31.5 ± 9.0 years), the development and validation sets comprised 497 and 424 patients, respectively. In the development set, the areas under the ROC curve for diagnosing hepatic steatosis were 0.920 for CS-MRI-PDFF and 0.915 for HISTO-MRS-PDFF. For ruling-out hepatic steatosis, the CS-MRI-PDFF cutoff was 2.3% (sensitivity, 92.4%; specificity, 63.0%) and the HISTO-MRI-PDFF cutoff was 2.6% (sensitivity, 88.8%; specificity, 70.1%). For ruling-in hepatic steatosis, the CS-MRI-PDFF cutoff was 3.5% (sensitivity, 73.5%; specificity, 88.6%) and the HISTO-MRI-PDFF cutoff was 4.0% (sensitivity, 74.7%; specificity, 90.6%). Conclusion In a large population of healthy adults, our study suggests diagnostic thresholds for ruling-out and ruling-in hepatic steatosis defined as HFF ≥ 5% by contemporary PDFF measurement methods.