Background: s/Aims: Reported incidence of extrahepatic bile duct cancer is higher in Asians than in Western populations. Korea, in particular, is one of the countries with the highest incidence rates of extrahepatic bile duct cancer in the world. Although research and innovative therapeutic modalities for extrahepatic bile duct cancer are emerging, clinical guidelines are currently unavailable in Korea. The Korean Society of Hepato-Biliary-Pancreatic Surgery in collaboration with related societies (Korean Pancreatic and Biliary Surgery Society, Korean Society of Abdominal Radiology, Korean Society of Medical Oncology, Korean Society of Radiation Oncology, Korean Society of Pathologists, and Korean Society of Nuclear Medicine) decided to establish clinical guideline for extrahepatic bile duct cancer in June 2021. Methods: Contents of the guidelines were developed through subgroup meetings for each key question and a preliminary draft was finalized through a Clinical Guidelines Committee workshop. Results: In November 2021, the finalized draft was presented for public scrutiny during a formal hearing. Conclusions The extrahepatic guideline committee believed that this guideline could be helpful in the treatment of patients.

Purpose: We prospectively compared the diagnostic accuracy of kidney dynamic computed tomography (KDCT), magnetic resonance imaging (MRI), and contrast-enhanced ultrasonography (CEUS) for the assessment of small renal mass (SRM) (≤4 cm). Materials and Methods: Seventy-six patients with SRM (mean age, 58.4±13.1 years) who underwent renal biopsy (n=11) or nephrectomy (partial or radical) (n=65) were enrolled. All patients underwent KDCT, MRI, and CEUS before renal biopsy or nephrectomy. Results: The mean maximal tumor size was 21.0±9.8 mm. The mean R.E.N.A.L nephrometry score was 7.0±1.7. Fifty-six patients had renal cell carcinoma (RCC) (clear cell, 42; papillary, 7; chromophobe, 5; succinate dehydrogenase deficient, 1; unspecified RCC, 1). Twenty patients had a benign tumor (angiomyolipoma, 11; oncocytoma, 3; others, 6). Clinicopathologic variables were comparable in RCC and benign groups. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of KDCT were 89.3%, 10.0%, 73.5%, and 25.0%, respectively. The sensitivity, specificity, PPV, and NPV of MRI were 89.3%, 10.0%, 73.5%, and 25.0%, respectively. The sensitivity, specificity, PPV, and NPV of CEUS were 85.7%, 50.0%, 82.8%, and 55.6%, respectively. The diagnostic accuracy of KDCT, MRI, and CEUS were 68.4%, 68.4%, and 76.3%, respectively. In a subgroup analysis based on clinical tumor size of 10 mm and 20 mm, CEUS also showed the highest diagnostic accuracy. Conclusions CEUS had the highest specificity, PPV, and NPV and may help improve the assessment of SRM.

Purpose: Resectable pancreatic ductal adenocarcinoma (PDAC) has a high risk of recurrence after curative resection; despite this, the preoperative risk factors for predicting early recurrence remain unclear. This study therefore aimed to identify preoperative inflammation and nutrition factors associated with early recurrence of resectable PDAC. Methods: From March 2021 to November 2021, a total of 20 patients who underwent curative resection for PDAC were enrolled in this study. We evaluated the risk factors for early recurrence within 1 year by univariate and multivariate analyses using Cox hazard proportional regression. The cutoff values for predicting recurrence were examined using receiver operating characteristic (ROC) curves. Results: In our univariate and multivariate analyses, C-reactive protein (CRP), CRP-albumin ratio, and CRP-prealbumin ratio, as well as sex and age, were significant independent prognostic factors for early recurrence in PDAC. However, known inflammatory factors (neutrophil-to-lymphocyte and platelet-to-lymphocyte ratios), nutritional factors (albumin, prealbumin, ferritin, vitamin D), and inflammatory-nutritional factors (Glasgow Prognostic Score, modified Glasgow Prognostic Score, albumin-bilirubin) showed no association with early recurrence. In addition, using cutoff values by ROC curve analysis, a high preoperative CRP level of >5 mg/L, as well as high CRP-to-albumin (>5.3) and CRP-to-prealbumin (>1.3) ratios showed no prognostic value. Conclusion Our results showed that inflammatory and perioperative nutritional factors, especially CRP-to-prealbumin ratio, have significant associations with early recurrence after curative resection in resectable PDAC. Therefore, for such patients, a cautious approach is needed when inflammation and poor nutritional status are present.

Purpose: In this study, polymerase chain reaction (PCR)-based microsatellite instability (MSI) testing was comprehensively analyzed and compared with immunohistochemistry (IHC) for mismatch repair (MMR) protein expression in patients with gastric cancer (GC). Materials and Methods: In 5,676 GC cases, PCR-based MSI testing using five microsatellites (BAT-26, BAT-25, D5S346, D2S123, and D17S250) and IHC for MLH1 were performed. Reevaluation of MSI testing/MLH1 IHC and additional IHC for MSH2, MSH6, and PMS2 were performed in discordant/indeterminate cases. Results: Of the 5,676 cases, microsatellite stable (MSS)/MSI-low and intact MLH1 were observed in 5,082 cases (89.5%), whereas MSI-high (MSI-H) and loss of MLH1 expression were observed in 502 cases (8.8%). We re-evaluated the remaining 92 cases (1.6%) with a discordant/ indeterminate status. Re-evaluation showed 1) 37 concordant cases (0.7%) (18 and 19 cases of MSI-H/MMR-deficient (dMMR) and MSS/MMR-proficient (pMMR), respectively), 2) 6 discordant cases (0.1%) (3 cases each of MSI-H/pMMR and MSS/dMMR), 3) 14 MSI indeterminate cases (0.2%) (1 case of dMMR and 13 cases of pMMR), and 4) 35 IHC indeterminate cases (0.6%) (22 and 13 cases of MSI-H and MSS, respectively). Finally, MSI-H or dMMR was observed in 549 cases (9.7%), of which 47 (0.8%) were additionally confirmed as MSI-H or dMMR by reevaluation. Sensitivity was 99.3% for MSI testing and 95.4% for MMR IHC. Conclusions Considering the low incidence of MSI-H or dMMR, discordant/indeterminate results were occasionally identified in GCs, in which case complementary testing is required.These findings could help improve the accuracy of MSI/MMR testing in daily practice.

Background/Aims: We investigated the factors related to spleen length and the diagnostic accuracy of a model using spleen length corrected by related factors, for the prediction of varices needing treatment (VNT). Methods: Various prediction models for VNT including spleen length were analyzed in the cohort of compensated advanced chronic liver disease (cACLD), defined as liver stiffness (LS) ≥10 kPa in a recent study. The associated factors for spleen length were identified in healthy subjects to improve the prediction of VNT. Results: Among 1,218 cACLD patients, VNT was noted in 249 patients (20.4%). On multivariate analysis, longer spleen length, lower platelet count, and higher LS value were independent predictors for VNT (all p<0.001). In multivariate analysis of 1,041 healthy subjects, age (β=–0.027), sex (β=0.762), and body mass index (β=0.097) were found to be significant factors for spleen length (all p<0.001). Using the β values, the estimated spleen length was calculated. To improve the prediction of VNT, the ratio of measured and estimated spleen length was calculated. Based on binary regression analysis results, the LS value-spleen ratio to platelet score (LSRPS) was calcu-lated as follows: 0.027×LS value (kPa)+2.690×measured/estimated spleen ratio–0.011×platelet count (cells×10 9 /L)–4.215. The area under the receiver operating characteristic of the LSRPS for VNT was 0.820, which was significantly higher than 0.797 of LS value-spleen diameter to plateletratio score (LSPS) (p=0.006). Conclusions Spleen length is influenced by age, sex, and body mass index in the Asian population. The LSRPS using the measured/estimated spleen ratio had higher diagnostic accuracy than LSPS in predicting VNT in patients with cACLD.

Purpose: Mycoplasma pneumoniae pneumonia (MP) is a major cause of community-acquired pneumonia (CAP) in children and is associated with extrapulmonary manifestations (EPM). The incidence and risk factors for EPM in children are unknown. Methods: This was a retrospective study involving 65,243 pediatric patients with CAP between 2010 and 2015 at 23 nationwide hospitals in South Korea. Medical records were reviewed to collect information regarding the clinical characteristics, radiological results, and laboratory findings. Logistic regression with multivariate analysis was performed to evaluate the risk factors associated with EPM in MP. Results: The incidence of EPM was 23.9%, including elevation of liver enzymes (18.1%), mucocutaneous manifestations (4.4%), proteinuria (4.1%), cardiovascular and neurological manifestations (0.4%), hematologic manifestations (0.2%), and arthritis (0.2%). Statistical analysis showed that mucocutaneous manifestations significantly increased with elevated alanine aminotransferase (adjusted odds ratio [aOR], 3.623; 95% confidence interval [CI], 1.933-6.790) and atopic sensitization (aOR, 2.973; 95% CI, 1.615–5.475) and decreased with respiratory virus coinfection (aOR, 0.273; 95% CI, 0.084–0.887). Elevated liver enzymes were significantly associated with elevated lactate dehydrogenase (aOR, 3.055; 95% CI, 2.257–4.137), presence of pleural effusion (aOR, 2.635; 95% CI, 1.767–3.930), and proteinuria with respiratory virus coinfection (aOR, 2.245; 95% CI, 1.113–4.527). Conclusion Approximately 24% of pediatric patients with MP had various EPM. As the risk factors associated with each EPM were different, it is necessary to evaluate the various clinical aspects and findings of MP to predict and prepare for the occurrence of EPM.

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.

Objective: Emergency medicine residents are expected to exhibit a poor health status due to excessive working hours and high stress. Because much of patient care depends on them, their health conditions will have a significant impact on patient outcomes. Our study was designed to analyze the health status of emergency medicine residents and the affecting factors using the 2019 Korean Emergency Medicine Residents Survey (KEMRS) results. Methods: The study evaluated the self-rated health-defined percentage of responders who thought they were in good health. Based on this response, the influencing factors were categorized statistically. These factors included personal characteristics, lifestyle (drinking, smoking, eating, sleeping, and exercise), and emotional stress. Results: Of a total of 384 respondents, 176 (46%) thought they were in good health. Participants who perceived themselves to be unhealthy included residents who were married, female, and those in the 3rd grade. Drinking and smoking were not perceived to affect health status, but regular exercise and proper eating patterns were seen to be positive influencing factors. Daytime sleepiness, depressive moods, and personal well-being were correlated with health status. Conclusion While personal characteristics and emotional problems cannot be changed easily, lifestyle changes can be made for better health. The health conditions of emergency residents have not been considered a matter of importance thus far. To overcome their health problems, responsible improvements in schedules and a program of long-term follow-ups need to be implemented, followed by training programs.