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: Although guidelines recommend vaccination for individuals who have recovered from the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection to prevent reinfection, comprehensive evaluation studies are limited. We aimed to evaluate vaccine effectiveness against SARS-CoV-2 reinfection according to the primary vaccination status, booster vaccination status, and vaccination methods used. Methods: This population-based case-control study enrolled all SARS-CoV-2-infected patients in Seoul between January 2020 and February 2022. Individuals were categorized into case (reinfection) and control (no reinfection) groups. Data were analyzed using conditional logistic regression after adjusting for underlying comorbidities using multiple regression. Results: The case group included 7,678 participants (average age: 32.26 years). In all vaccinated individuals, patients who received the first and second booster doses showed reduced reinfection rates compared with individuals who received basic vaccination (odds ratio [OR] = 0.605, P < 0.001 and OR = 0.002, P < 0.001). Patients who received BNT162b2 or mRNA-1273, NVX-CoV2373 and heterologous vaccination showed reduced reinfection rates compared with unvaccinated individuals (OR = 0.546, P < 0.001; OR = 0.356, P < 0.001; and OR = 0.472, P < 0.001). However, the ChAdOx1-S or Ad26.COV2.S vaccination group showed a higher reinfection rate than the BNT162b2 or mRNA-1273 vaccination group (OR = 4.419, P < 0.001). Conclusion In SARS-CoV-2-infected individuals, completion of the basic vaccination series showed significant protection against reinfection compared with no vaccination. If the first or second booster vaccination was received, the protective effect against reinfection was higher than that of basic vaccination; when vaccinated with BNT162b2 or mRNA-1273 only or heterologous vaccination, the protective effect was higher than that of ChAdOx1-S or Ad26.COV2.S vaccination only.

Objective: Traumatic brain injury (TBI) is one of the major causes of death and disability in children. Understanding the epidemiologic characteristics of TBI in children is the first step for developing preventative strategies, optimizing care systems, and rehabilitating the injury. Methods: This is a cross-sessional study based on the Emergency Department-based Injury In-depth Surveillance (EDIIS) in Korea. We identified children (aged 0 to 18 years) who presented with TBI in emergency departments between January 2011 and December 2018. Subjects were classified into four groups according to age and development: infant and toddler group (0-2 years), pre-school group (3-5 years), school-aged group (6-11 years), and adolescent group (12-18 years). Epidemiologic characteristics and outcomes were compared according to age groups, and temporal variability in incidence was evaluated. Results: During the 8-year study period, 45,734 children with TBI were included in the analysis. A higher incidence of TBI was observed in males, road accidents, and school/educational facilities as compared to the lesser-aged group (all P<0.01). Motor vehicle collisions were more common in the older group, but falls were more common in the younger group. Compared to the infant/toddler group, the adolescent group had higher intracranial injuries (8.1% vs. 16.8%; adjusted odds ratio [AOR], 1.8; 95% confidence interval [CI], 1.6-2.0) and mortality rate (0.2% vs. 1.3%; AOR, 2.0; 95% CI, 1.3-3.0). Conclusion The epidemiological characteristics of TBI in children are different for each group. It is necessary to develop differentiated preventative strategies and treatment systems based on the age groups of children.

Tixagevimab/cilgavimab is a monoclonal antibody used to prevent coronavirus disease 2019 among immunocompromised hosts and maintained neutralizing activity against early omicron variants. Omicron BN.1 became a dominant circulating strain in Korea early 2023, but its susceptibility to tixagevimab/cilgavimab is unclear. We conducted plaque reduction neutralization test (PRNT) against BN.1 in a prospective cohort (14 patients and 30 specimens). BN.1 PRNT was conducted for one- and three-months after tixagevimab/ cilgavimab administration and the average PRNT ND 50 of each point was lower than the positive cut-off value of 20 (12.9 ± 4.5 and 13.2 ± 4.2, respectively, P = 0.825). In the paired analyses, tixagevimab/cilgavimab-administered sera could not actively neutralize BN.1 (PRNT ND 50 11.5 ± 2.9, P = 0.001), compared with the reserved activity against BA.5 (ND 50 310.5 ± 180.4). Unlike virus-like particle assay, tixagevimab/cilgavimab was not active against BN.1 in neutralizing assay, and would not be effective in the present predominance of BA.2.75 sublineages.

Objectives: Gastrointestinal cytomegalovirus (CMV) disease is a major contributor to mortality in immunocompromised patients. Few studies have discussed upper gastrointestinal CMV (UGICMV) disease in immunocompetent patients. We compared the clinical outcomes of UGI-CMV between immunocompromised and immunocompetent patients. Methods: This retrospective study included patients with UGI-CMV disease from five tertiary hospitals across Korea (2010– 2022). Patients’ clinical data and outcomes were recorded. Results: UGI-CMV was diagnosed in 54 patients; 27 (50.0%) had esophageal, 24 (44.4%) had gastric, and 3 patients (5.6%) had duodenal involvement. Patients’ median age was 64 years (interquartile range 53–75 years), and the most common comorbidities included hypertension (57.4%) and diabetes (38.9%). The predominant symptom was abdominal pain (46.3%), and the most common endoscopic finding was ulcers (70.4%). Antiviral treatment was administered to 31 patients, and 23 patients underwent observation without treatment. We investigated 32 immunocompromised (59.3%) and 22 immunocompetent (40.7%) patients and observed no intergroup differences in comorbidities and in laboratory and endoscopic findings. Immunocompromised patients had longer length of hospitalization (median 46.2 days vs. 20.0 days, p=0.001). However, treatment outcomes, including the need for intensive care unit admission and mortality did not significantly differ. The overall mortality rate was 13.0%; one patient from the immunocompromised group died of UGI-CMV disease. The treatment success rate was higher in immunocompromised patients who received antiviral therapy (p=0.011). Conclusions UGI-CMV disease is not uncommon in immunocompetent patients, although symptoms are milder than those in immunocompromised patients. Our findings emphasize the importance of clinical vigilance for accurate diagnosis of CMV infection, particularly in susceptible symptomatic patients and highlight the need for active antiviral treatment for management of immunocompromised patients.

Background/Aims: Globally, the population aged 80 years or older is growing faster due to the rising life expectancy. Korea has already entered into an advanced aged society, and a post-aged society is expected in 2025. This study evaluated the patterns of gastrointestinal disease in the population aged 80 years or older during the recent decade in Korea.Method: This study retrospectively reviewed the medical records of patients admitted to the gastrointestinal department of Suwon St. Vincent’s hospital, Incheon St. Mary’s hospital, and Uijeongbu St. Mary's Hospital ― general hospitals of Seoul-Gyeonggi province in Korea. It was a repeated cross-sectional study in 2009 and 2019. Results: The number of admitted patients aged 80 years or older increased from 549 (9.0%) in 2009 to 1,073 (14.4%) in 2019 (p<0.01). As for the in-hospital mortality, there was no significant difference (p=0.25). On the other hand, the combined morbidities increased, and the duration of admission also increased (7.2±7.8 days vs. 8.1±8.2 days, p=0.03). The number of upper gastrointestinal hemorrhage and patients who are bleeding associated with drugs users increased (p<0.01). The proportion of lower gastrointestinal disease decreased (p<0.01) because of the decrease in procedure-related admissions (p<0.01). The number of those with pancreaticobiliary tract disease increased markedly (p<0.01), and the rate of cases that could not perform the procedure decreased (p=0.04). Conclusion The patterns of gastrointestinal disease in the population aged 80 years or older have changed in the recent decade in Korea. Hence, more preparation for this medical environment is needed.

Background: Nilotinib is a tyrosine kinase inhibitor approved by the Ministry of Food and Drug Safety for frontline and 2nd line treatment of Philadelphia chromosome-positive chronic myeloid leukemia (Ph+ CML). This study aimed to confirm the safety and efficacy of nilotinib in routine clinical practice within South Korea. Methods: An open-label, multicenter, single-arm, 12-week observational post-marketing surveillance (PMS) study was conducted on 669 Korean adult patients with Ph + CML from December 24, 2010, to December 23, 2016. The patients received nilotinib treatment in routine clinical practice settings. Safety was evaluated by all types of adverse events (AEs) during the study period, and efficacy was evaluated by the complete hematological response (CHR) and cytogenetic response. Results: During the study period, AEs occurred in 61.3% (410 patients, 973 events), adverse drug reactions (ADRs) in 40.5% (271/669 patients, 559 events), serious AEs in 4.5% (30 patients, 37 events), and serious ADRs in 0.7% (5 patients, 8 events). Furthermore, unexpected AEs occurred at a rate of 6.9% (46 patients, 55 events) and unexpected ADRs at 1.2% (8 patients, 8 events). As for the efficacy results, CHR was achieved in 89.5% (442/494 patients), and minor cytogenetic response or major cytogenetic response was achieved in 85.8% (139/162 patients). Conclusion This PMS study shows consistent results in terms of safety and efficacy compared with previous studies. Nilotinib was well tolerated and efficacious in adult Korean patients with Ph + CML in routine clinical practice settings.

Background/Aims: The prospective Crohn’s Disease Clinical Network and Cohort Study is a nationwide multicenter cohort study of patients with Crohn’s disease (CD) in Korea, aiming to prospectively investigate the clinical features and long-term prognosis associated with CD. Methods: Patients diagnosed with CD between January 2009 and September 2019 were prospectively enrolled. They were divided into two cohorts according to the year of diagnosis: cohort 1 (diagnosed between 2009 and 2011) versus cohort 2 (between 2012 and 2019). Results: A total of 1,175 patients were included, and the median follow-up duration was 68 months (interquartile range, 39.0 to 91.0 months). The treatment-free durations for thiopurines (p<0.001) and anti-tumor necrosis factor agents (p=0.018) of cohort 2 were shorter than those of cohort 1. Among 887 patients with B1 behavior at diagnosis, 149 patients (16.8%) progressed to either B2 or B3 behavior during follow-up. Early use of thiopurine was associated with a reduced risk of behavioral progression (adjusted hazard ratio [aHR], 0.69; 95% confidence interval [CI], 0.50 to 0.90), and family history of inflammatory bowel disease was associated with an increased risk of behavioral progression (aHR, 2.29; 95% CI, 1.16 to 4.50). One hundred forty-one patients (12.0%) underwent intestinal resection, and the intestinal resection-free survival time was significantly longer in cohort 2 than in cohort 1 (p=0.003). The early use of thiopurines (aHR, 0.35;95% CI, 0.23 to 0.51) was independently associated with a reduced risk of intestinal resection. Conclusions The prognosis of CD in Korea appears to have improved over time, as evidenced by the decreasing intestinal resection rate. Early use of thiopurines was associated with an improved prognosis represented by a reduced risk of intestinal resection.

Purpose: In this trial, we investigated the efficacy and safety of adjuvant letrozole for hormone receptor (HR)-positive breast cancer. Here, we report the clinical outcome in postmenopausal women with HR-positive breast cancer treated with adjuvant letrozole according to estrogen receptor (ER) expression levels. Methods: In this multi-institutional, open-label, observational study, postmenopausal patients with HR-positive breast cancer received adjuvant letrozole (2.5 mg/daily) for 5 years unless they experienced disease progression or unacceptable toxicity or withdrew their consent. The patients were stratified into the following 3 groups according to ER expression levels using a modified Allred score (AS): low, intermediate, and high (AS 3–4, 5–6, and 7–8, respectively). ER expression was centrally reviewed. The primary objective was the 5-year disease-free survival (DFS) rate. Results: Between April 25, 2010, and February 5, 2014, 440 patients were enrolled. With a median follow-up of 62.0 months, the 5-year DFS rate in all patients was 94.2% (95% confidence interval [CI], 91.8–96.6). The 5-year DFS and recurrence-free survival (RFS) rates did not differ according to ER expression; the 5-year DFS rates were 94.3% and 94.1%in the low-to-intermediate and high expression groups, respectively (p = 0.6), and the corresponding 5-year RFS rates were 95.7% and 95.4%, respectively (p = 0.7). Furthermore, 25 patients discontinued letrozole because of drug toxicity. Conclusion Treatment with adjuvant letrozole showed very favorable treatment outcomes and good tolerability among Korean postmenopausal women with ER-positive breast cancer, independent of ER expression.