Background and Objectives: Concerns remain that early aspirin cessation may be associated with potential harm in subsets at high risk of ischemic events. This study aimed to assess the effects of P2Y12 inhibitor monotherapy after 3-month dual antiplatelet therapy (DAPT) vs.prolonged DAPT (12-month or longer) based on the ischemic risk stratification, the CHADSP2A2RC, after percutaneous coronary intervention (PCI). Methods: This was a sub-study of the SMART-CHOICE trial. The effect of the randomized antiplatelet strategies was assessed across 3 CHADS-P2A2RC risk score categories. The primary outcome was a major adverse cardiac and cerebral event (MACCE), a composite of all-cause death, myocardial infarction, or stroke. Results: Up to 3 years, the high CHADS-P2A2RC risk score group had the highest incidence of MACCE (105 [12.1%], adjusted hazard ratio [HR], 2.927; 95% confidence interval [CI], 1.358–6.309; p=0.006) followed by moderate-risk (40 [1.4%], adjusted HR, 1.786; 95% CI, 0.868–3.674; p=0.115) and low-risk (9 [0.5%], reference). In secondary analyses, P2Y12 inhibitor monotherapy reduced the Bleeding Academic Research Consortium (BARC) types 2, 3, or 5 bleeding without increasing the risk of MACCE as compared with prolonged DAPT across the 3 CHADS-P2A2RC risk strata without significant interaction term (interaction p for MACCE=0.705 and interaction p for BARC types 2, 3, or 5 bleeding=0.055). Conclusions The CHADS-P2A2RC risk score is valuable in discriminating high-ischemicrisk patients. Even in such patients with a high risk of ischemic events, P2Y12 inhibitor monotherapy was associated with a lower incidence of bleeding without increased risk of ischemic events compared with prolonged DAPT.

Purpose: Long-course chemoradiotherapy (LCRT) has been widely recommended in a majority of rectal cancer patients. Recently, encouraging data on short-course radiotherapy (SCRT) for rectal cancer has emerged. In this study, we aimed to compare these two methods in terms of short-term outcomes and cost analysis under the Korean medical insurance system. Materials and Methods: Sixty-two patients with high-risk rectal cancer, who underwent either SCRT or LCRT followed by total mesorectal excision (TME), were classified into two groups. Twenty-seven patients received 5 Gy×5 with two cycles of XELOX (capecitabine 1000 mg/m 2 and oxaliplatin 130 mg/m 2 every 3 weeks) followed by TME (SCRT group). Thirty-five patients received capecitabine-based LCRT followed by TME (LCRT group). Short-term outcomes and cost estimation were assessed between the two groups. Results: Pathological complete response was achieved in 18.5% and 5.7% of patients in the SCRT and LCRT groups, respectively (p=0.223). The 2-year recurrence-free survival rate did not show significant difference between the two groups (SCRT vs. LCRT:91.9% vs. 76.2%, p=0.394). The average total cost per patient for SCRT was 18% lower for inpatient treatment (SCRT vs. LCRT: $18787 vs. $22203, p<0.001) and 40% lower for outpatient treatment (SCRT vs. LCRT: $11955 vs. $19641, p<0.001) compared to LCRT. SCRT was shown to be the dominant treatment option with fewer recurrences and fewer complications at a lower cost. Conclusion SCRT was well-tolerated and achieved favorable short-term outcomes. In addition, SCRT showed significant reduction in the total cost of care and distinguished cost-effectiveness compared to LCRT.

Purpose: The incidence and prognostic implications of atrial fibrillation (AF) in patients with severe aortic stenosis (AS) undergoing transcatheter aortic valve implantation (TAVI) are controversial, especially for Korean patients. Furthermore, the pattern of antithrombotic therapy for these patients is unknown. The present study sought to identify the impact of AF on Korean patients undergoing TAVI and demonstrate the status of antithrombotic therapy for these patients. Materials and Methods: A total of 660 patients who underwent TAVI for severe AS were recruited from the nationwide K-TAVI registry in Korea. The enrolled patients were stratified into sinus rhythm (SR) and AF groups. The primary endpoint was all-cause death at 1-year. Results: AF was recorded in 135 patients [pre-existing AF 108 (16.4%) and new-onset AF 27 (4.1%)]. The rate of all-cause death at 1 year was significantly higher in patients with AF than in those with SR [16.2% vs. 6.4%, adjusted hazard ratio (HR): 2.207, 95% confidence interval (CI): 1.182–4.120, p=0.013], regardless of the onset timing of AF. The rate of new pacemaker insertion at 1 year was also significantly higher in patients with AF than in those with SR (14.0% vs. 5.5%, adjusted HR: 3.137, 95%CI: 1.621–6.071, p=0.001).Among AF patients, substantial number of patients received the combination of multiple antithrombotic agents (77.8%), and the most common combination was that of aspirin and clopidogrel (38.1%). Conclusion AF was an independent predictor of 1-year mortality and new pacemaker insertion in Korean patients undergoing TAVI.

Purpose: Renal tumors account for approximately 7% of all childhood cancers. These include Wilms tumor (WT), clear cell sarcoma of the kidney (CCSK), malignant rhabdoid tumor of the kidney (MRTK), renal cell carcinoma (RCC), congenital mesoblastic nephroma (CMN) and other rare tumors. We investigated the epidemiology of pediatric renal tumors in Korea. Materials and Methods: From January 2001 to December 2015, data of pediatric patients (0–18 years) newly-diagnosed with renal tumors at 26 hospitals were retrospectively analyzed. Results: Among 439 patients (male, 240), the most common tumor was WT (n=342, 77.9%), followed by RCC (n=36, 8.2%), CCSK (n=24, 5.5%), MRTK (n=16, 3.6%), CMN (n=12, 2.7%), and others (n=9, 2.1%). Median age at diagnosis was 27.1 months (range 0-225.5) and median follow-up duration was 88.5 months (range 0-211.6). Overall, 32 patients died, of whom 17, 11, 1, and 3 died of relapse, progressive disease, second malignant neoplasm, and treatment-related mortality. Five-year overall survival and event free survival were 97.2% and 84.8% in WT, 90.6% and 82.1% in RCC, 81.1% and 63.6% in CCSK, 60.3% and 56.2% in MRTK, and 100% and 91.7% in CMN, respectively (p < 0.001). Conclusion The pediatric renal tumor types in Korea are similar to those previously reported in other countries. WT accounted for a large proportion and survival was excellent. Non-Wilms renal tumors included a variety of tumors and showed inferior outcome, especially MRTK. Further efforts are necessary to optimize the treatment and analyze the genetic characteristics of pediatric renal tumors in Korea.

Gastric cancer is one of the most common cancers in Korea and the world. Since 2004, this is the 4th gastric cancer guideline published in Korea which is the revised version of previous evidence-based approach in 2018. Current guideline is a collaborative work of the interdisciplinary working group including experts in the field of gastric surgery, gastroenterology, endoscopy, medical oncology, abdominal radiology, pathology, nuclear medicine, radiation oncology and guideline development methodology. Total of 33 key questions were updated or proposed after a collaborative review by the working group and 40 statements were developed according to the systematic review using the MEDLINE, Embase, Cochrane Library and KoreaMed database. The level of evidence and the grading of recommendations were categorized according to the Grading of Recommendations, Assessment, Development and Evaluation proposition. Evidence level, benefit, harm, and clinical applicability was considered as the significant factors for recommendation. The working group reviewed recommendations and discussed for consensus. In the earlier part, general consideration discusses screening, diagnosis and staging of endoscopy, pathology, radiology, and nuclear medicine. Flowchart is depicted with statements which is supported by meta-analysis and references. Since clinical trial and systematic review was not suitable for postoperative oncologic and nutritional follow-up, working group agreed to conduct a nationwide survey investigating the clinical practice of all tertiary or general hospitals in Korea. The purpose of this survey was to provide baseline information on follow up. Herein we present a multidisciplinary-evidence based gastric cancer guideline.

Chronic constipation is one of the most common digestive diseases encountered in clinical practice. Constipation manifests as a variety of symptoms, such as infrequent bowel movements, hard stools, feeling of incomplete evacuation, straining at defecation, a sense of anorectal blockage during defecation, and use of digital maneuvers to assist defecation. During the diagnosis of chronic constipation, the Bristol Stool Form Scale, colonoscopy, and a digital rectal examination are useful for objective symptom evaluation and differential diagnosis of secondary constipation. Physiological tests for functional constipation have complementary roles and are recommended for patients who have failed to respond to treatment with available laxatives and those who are strongly suspected of having a defecatory disorder. As new evidence on the diagnosis and management of functional constipation emerged, the need to revise the previous guideline was suggested. Therefore, these evidence-based guidelines have proposed recommendations developed using a systematic review and meta-analysis of the treatment options available for functional constipation. The benefits and cautions of new pharmacological agents (such as lubiprostone and linaclotide) and conventional laxatives have been described through a meta-analysis. The guidelines consist of 34 recommendations, including 3 concerning the definition and epidemiology of functional constipation, 9 regarding diagnoses, and 22 regarding managements. Clinicians (including primary physicians, general health professionals, medical students, residents, and other healthcare professionals) and patients can refer to these guidelines to make informed decisions regarding the management of functional constipation.

Objective: Disruptive behavior disorder (DBD) adversely impacts children and adolescents. However, a comprehensive and cost-effective scale to assess DBD is lacking in Korea. Therefore, this study translated the Disruptive Behavior Disorders Rating Scale (DBDRS) into Korean and analyzed its psychometric properties. Methods: Parents and primary caregivers of non-clinical (n=429) and clinical (n=28) children and adolescents aged 6–15 years were included in the analysis. Confirmatory factor analysis was conducted; further, concurrent validity and internal consistency were investigated using correlation analysis and Cronbach’s alpha, respectively. Furthermore, discriminative capacity was estimated using receiver operating characteristic curve analysis. Results: The four-factor model of K-DBDRS showed good model fit indices and factor loadings, which supported the construct validity of the scale. Strong correlations between K-DBDRS and related measurements were observed, and a robust level of Cronbach’s alpha was confirmed (0.891–0.933). The discriminative capacity of the scale was good, based on the area under the curve values (0.933–0.953). Conclusion This study indicated that the K-DBDRS is an appropriate screening tool for Korean children and adolescents. Thus, this scale can be applied in clinical and community settings to identify children and adolescents with disruptive behavior disorders.

Purpose: Atypical teratoid/rhabdoid tumor (ATRT) is a highly aggressive malignancy with peak incidence in children aged less than 3 years. Standard treatment for central nervous system ATRT in children under the age of 3 years have not been established yet. The objective of this study was to analyze characteristics and clinical outcomes of ATRT in children aged less than 3 years. Materials and Methods: A search of medical records from seven centers was performed between January 2005 and December 2016. Results: Forty-three patients were enrolled. With a median follow-up of 90 months, 27 patients (64.3%) showed at least one episode of disease progression (PD). The first date of PD was at 160 days after diagnosis. The 1- and 3-year progression-free survivals (PFS) were 51.2% and 28.5%, respectively. The 1- and 3-year overall survivals were 61.9% and 38.1%, respectively. The 3-year PFS was improved from 0% in pre-2011 to 47.4% in post-2011. Excluding one patient who did not receive any further therapy after surgery, 27 patients died due to PD (n=21), treatment-related toxicity (n=5), or unknown cause (n=1). In univariate analysis, factors associated with higher 3-year PFS were no metastases, diagnosis after 2011, early adjuvant radiotherapy, and high-dose chemotherapy (HDCT). In multivariate analysis, the use of HDCT and adjuvant radiotherapy remained significant prognostic factors for PFS (both p < 0.01). Conclusion Aggressive therapy including early adjuvant radiotherapy and HDCT could be considered to improve outcomes of ATRT in children under the age of 3 years.