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.

Chronic rhinosinusitis (CRS) is characterized by prolonged inflammation of the nasal and paranasal sinus mucosa lasting over 12 weeks. CRS is divided into two main types based on the presence of nasal polyps: CRS without nasal polyps and CRS with nasal polyps. The condition is further classified into endotypes based on type 1, type 2, and type 3 inflammatory signatures, with differences in terms of disease severity, prognosis, and treatment response. Recent studies have emphasized the importance of the epithelial-mesenchymal transition (EMT) in CRS progression. In CRS, the EMT can be triggered by infections, allergens, hypoxia, and environmental pollutants. Specifically, EMT induction proceeds through the following mechanisms: viral and bacterial infections disrupt the epithelial barrier, house dust mites and other allergens activate the TGF-β and EGFR signaling pathways, hypoxia increases HIF-1α and other mesenchymal markers, and diesel exhaust particles and particulate matter cause oxidative stress. Maintaining the integrity of the epithelial barrier is essential for nasal mucosa homeostasis. In CRS, barrier damage activates repair processes that trigger the EMT, resulting in barrier dysfunction and tissue remodeling. Epithelial barrier dysfunction allows antigens and pathogens to penetrate, perpetuating inflammation and promoting the EMT. This disruption is a hallmark of CRS, emphasizing the importance of barrier integrity in the development of the disease. Key signaling pathways regulating the EMT in CRS include TGF-β, Wnt, HMGB1, AGE/ERK, TNF-α, and various miRNAs. These signaling pathways connect to various downstream pathways, such as the Smad2/3, GSK-3β/β-catenin, RAGE, and NF-κB pathways. This review focuses on the complex mechanisms of the EMT in CRS, emphasizing the role of epithelial barrier dysfunction and subsequent EMT processes in driving the disease’s development and progression. A deeper understanding of these EMT-driven mechanisms will help identify the potential therapeutic targets aimed at restoring epithelial integrity and reversing the EMT.

Purpose: This study aimed to assess the difference in the vascular parameters of perfusion in the optic nerve head in normal tension glaucoma (NTG) across disease stages using optical coherence tomography angiography and its correlation with peripapillary retinal nerve fiber layer (RNFL) thickness. Methods: In this retrospective study, 83 eyes with varying stages of NTG (25 mild, 31 moderate, and 27 severe) and 90 healthy eyes were enrolled. The perfusion density (PD) and flux index (FI) of the optic nerve head divided into four sectors were determined. We compared the vascular, structural, and functional parameters between normal and glaucomatous eyes and performed a subgroup analysis among the NTG stages. Pearson correlation coefficient was used to assess the topographic correlation between vascular parameters and RNFL thickness. Results: PD and FI were significantly decreased in the NTG group. Subgroup analysis revealed a significant decrease in vascular parameters in most regions in the NTG group, except for the nasal PD and temporal FI. Post hoc analysis showed a significant decrease in PD in the inferior region across all severity levels (mild vs. moderate, p = 0.012; moderate vs. severe, p = 0.012; mild vs. severe, p < 0.001). PD and FI were strongly correlated with RNFL thickness in all quadrants (all p < 0.001), with the strongest correlation observed in the inferior region. Conclusions Vascular parameters were significantly decreased in glaucomatous eyes, and the degree of decrease in vascular parameters was proportional to glaucoma severity. Peripapillary perfusion analysis using optical coherence tomography angiography may complement other measurements used for glaucoma diagnosis.

Background and Objectives: The aim of this study was to examine the clinical characteristics and prognosis of chronic rhinosinusitis with nasal polyps (CRSwNP) following endoscopic sinus surgery (ESS), focusing on distinct histological endotypes characterized by eosinophil and neutrophil infiltration.Subjects and Method A total of 207 patients diagnosed with CRSwNP who underwent ESS between August 2014 and September 2018 were included in the study. Patients were categorized into different groups based on eosinophil and neutrophil counts in the tissues. The demographic data, Lund-Mackay score, Lund-Kennedy (L-K) endoscopic score, Sino-Nasal Outcome Test-22 and Kaplan-Meier estimation were analyzed according to different histologic endotypes. Results: The histologic types were divided into four groups: the eosinophilic polyp (EP)+ neutrophlic polyp (NP) group, the EP group, the NP group, and the nonEP+nonNP group. Among the groups, the highest level of inflammation (L-K score, p<0.05) was observed in the EP+NP group, and the worst prognosis was observed in the EP+NP group according to the results of the Kaplan-Meier analysis (p<0.001). Conclusion Compared to non-neutrophil-infiltration polyps, neutrophil infiltration was associated with worse outcome when it was accompanied with eosinophilic infiltration. This discovery underlines how crucial it is to take neutrophils in nasal polyps into account in order to better understand their clinical behavior and maybe design customized treatments for better patient outcomes.

Purpose: The increase in thyroid cancer incidence has inevitably led to an increase in thyroid cancer surgeries. This meta-regression analysis aimed to determine if the rate of post-thyroidectomy complications changes by year. Materials and Methods: PubMed and Embase databases were used to perform a systematic literature search of studies published from January 1, 2005, using the keywords “thyroidectomy” and “complication.” A meta-regression was performed for post-thyroidectomy hypocalcemia and bleeding. Results: This meta-analysis included 25 studies involving 927751 individuals. Through the years of publications in this study, there was no significant difference in the proportion of post-thyroidectomy hypocalcemia and bleeding (p=0.9978, 0.6393). Conclusion Although the number of thyroid surgeries has recently increased, the incidence of post-thyroidectomy hypocalcemia and bleeding did not significantly increase.

Background: Current international guidelines recommend against deep sedation as it is associated with worse outcomes in the intensive care unit (ICU). However, in Korea the prevalence of deep sedation and its impact on patients in the ICU are not well known. Methods: From April 2020 to July 2021, a multicenter, prospective, longitudinal, noninterventional cohort study was performed in 20 Korean ICUs. Sedation depth extent was divided into light and deep using a mean Richmond Agitation–Sedation Scale value within the first 48 hours. Propensity score matching was used to balance covariables; the outcomes were compared between the two groups. Results: Overall, 631 patients (418 [66.2%] and 213 [33.8%] in the deep and light sedation groups, respectively) were included. Mortality rates were 14.1% and 8.4% in the deep and light sedation groups (P = 0.039), respectively. Kaplan-Meier estimates showed that time to extubation (P < 0.001), ICU length of stay (P = 0.005), and death P = 0.041) differed between the groups. After adjusting for confounders, early deep sedation was only associated with delayed time to extubation (hazard ratio [HR], 0.66; 95% confidence inter val [CI], 0.55– 0.80; P < 0.001). In the matched cohort, deep sedation remained significantly associated with delayed time to extubation (HR, 0.68; 95% 0.56–0.83; P < 0.001) but was not associated with ICU length of stay (HR, 0.94; 95% CI, 0.79–1.13; P = 0.500) and in-hospital mortality (HR, 1.19; 95% CI, 0.65–2.17; P = 0.582). Conclusion In many Korean ICUs, early deep sedation was highly prevalent in mechanically ventilated patients and was associated with delayed extubation, but not prolonged ICU stay or in-hospital death.

Purpose: Visible scars on the neck caused by thyroid surgery give rise to significant aesthetic, functional, and psychosocial problems. The objective of this study is to comparatively investigate the public perception of neck scar cosmesis in Turkish and South Korean populations. Methods: This survey was prepared to collect participants’ demographic and socioeconomic data and determine their perception of scar cosmesis on the neck and consisted of 15 questions. One thousand thirty-nine individuals who did not undergo thyroid surgery completed the survey. The P-values of <0.05 were deemed to indicate statistical significance. Results: There were 1,039 respondents, of whom 525 (50.5%) were Turkish and 514 (49.5%) were South Korean. South Korean respondents stated that they would be significantly more uncomfortable with the thought of having a scar due to thyroid surgery, compared to the Turkish respondents (P < 0.001). The South Korean respondents stated that they would be significantly more concerned about the scar’s length, thickness, and darkening color, compared to the Turkish respondents (P < 0.001 for all cases). Conclusion Patients’ expectations, which are affected by various sociodemographic factors and cultural characteristics, are as important as the medical condition when deciding on the type of thyroid surgery. The study findings clearly indicated that the South Korean population would be significantly more uncomfortable with having a scar on the neck, compared to the Turkish population. Therefore, in selected cases, a scarless thyroidectomy approach, such as transoral endoscopic thyroidectomy, vestibular approach may be preferable for societies like South Korea.

Purpose: There are no reliable biomarkers to guide treatment for patients with borderline resectable pancreatic cancer (BRPC) in the neoadjuvant setting. We used plasma circulating tumor DNA (ctDNA) sequencing to search biomarkers for patients with BRPC receiving neoadjuvant mFOLFIRINOX in our phase 2 clinical trial (NCT02749136). Materials and Methods: Among the 44 patients enrolled in the trial, patients with plasma ctDNA sequencing at baseline or post-operation were included in this analysis. Plasma cell-free DNA isolation and sequencing were performed using the Guardant 360 assay. Detection of genomic alterations, including DNA damage repair (DDR) genes, were examined for correlations with survival. Results: Among the 44 patients, 28 patients had ctDNA sequencing data qualified for the analysis and were included in this study. Among the 25 patients with baseline plasma ctDNA data, 10 patients (40%) had alterations of DDR genes detected at baseline, inclu-ding ATM, BRCA1, BRCA2 and MLH1, and showed significantly better progression-free survival than those without such DDR gene alterations detected (median, 26.6 vs. 13.5 months; log-rank p=0.004). Patients with somatic KRAS mutations detected at baseline (n=6) had significantly worse overall survival (median, 8.5 months vs. not applicable; log-rank p=0.003) than those without. Among 13 patients with post-operative plasma ctDNA data, eight patients (61.5%) had detectable somatic alterations. Conclusion Detection of DDR gene mutations from plasma ctDNA at baseline was associated with better survival outcomes of pati-ents with borderline resectable pancreatic ductal adenocarcinoma treated with neoadjuvant mFOLFIRINOX and may be a prognostic biomarker.

OBJECTIVES: We estimated the population prevalence of antibodies to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), including unreported infections, through a Korea Seroprevalence Study of Monitoring of SARS-CoV-2 Antibody Retention and Transmission (K-SEROSMART) in 258 communities throughout Korea. METHODS: In August 2022, a survey was conducted among 10,000 household members aged 5 years and older, in households selected through two stage probability random sampling. During face-to-face household interviews, participants self-reported their health status, COVID-19 diagnosis and vaccination history, and general characteristics. Subsequently, participants visited a community health center or medical clinic for blood sampling. Blood samples were analyzed for the presence of antibodies to spike proteins (anti-S) and antibodies to nucleocapsid proteins (anti-N) SARS-CoV-2 proteins using an electrochemiluminescence immunoassay. To estimate the population prevalence, the PROC SURVEYMEANS statistical procedure was employed, with weighting to reflect demographic data from July 2022. RESULTS: In total, 9,945 individuals from 5,041 households were surveyed across 258 communities, representing all basic local governments in Korea. The overall population-adjusted prevalence rates of anti-S and anti-N were 97.6% and 57.1%, respectively. Since the Korea Disease Control and Prevention Agency has reported a cumulative incidence of confirmed cases of 37.8% through July 31, 2022, the proportion of unreported infections among all COVID-19 infection was suggested to be 33.9%. CONCLUSIONS The K-SEROSMART represents the first nationwide, community-based seroepidemiologic survey of COVID-19, confirming that most individuals possess antibodies to SARS-CoV-2 and that a significant number of unreported cases existed. Furthermore, this study lays the foundation for a surveillance system to continuously monitor transmission at the community level and the response to COVID-19.

Bacillus Calmette-Guerin (BCG) vaccine is the only licensed vaccine for tuberculosis (TB) prevention. Previously, our group demonstrated the vaccine potential of Rv0351 and Rv3628 against Mycobacterium tuberculosis (Mtb) infection by directing Th1-biased CD4 + T cells coexpressing IFN-γ, TNF-α, and IL-2 in the lungs. Here, we assessed immunogenicity and vaccine potential of the combined Ags (Rv0351/Rv3628) formulated in different adjuvants as subunit booster in BCG-primed mice against hypervirulent clinical Mtb strain K (Mtb K). Compared to BCG-only or subunit-only vaccine, BCG prime and subunit boost regimen exhibited significantly enhanced Th1 response. Next, we evaluated the immunogenicity to the combined Ags when formulated with four different types of monophosphoryl lipid A (MPL)-based adjuvants: 1) dimethyldioctadecylammonium bromide (DDA), MPL, and trehalose dicorynomycolate (TDM) in liposome form (DMT), 2) MPL and Poly I:C in liposome form (MP), 3) MPL, Poly I:C, and QS21 in liposome form (MPQ), and 4) MPL and Poly I:C in squalene emulsion form (MPS). MPQ and MPS displayed greater adjuvancity in Th1 induction than DMT or MP did. Especially, BCG prime and subunit-MPS boost regimen significantly reduced the bacterial loads and pulmonary inflammation against Mtb K infection when compared to BCG-only vaccine at a chronic stage of TB disease. Collectively, our findings highlighted the importance of adjuvant components and formulation to induce the enhanced protection with an optimal Th1 response.