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.

This study was conducted to investigate potential differences in vaccine efficacy between patients undergoing palliative chemotherapy and receiving adjuvant chemotherapy. Additionally, the study proved the influence of vaccination timing on vaccine efficacy during active chemotherapy. Anti-receptor-binding domain (RBD) IgG binding antibody assays and surrogate neutralizing antibody assays were performed after BNT162b2 or mRNA-1273 vaccination in 45 solid cancer patients (23 adjuvant and 22 palliative chemotherapy) and in 24 healthy controls before vaccination (baseline), at every two to four weeks after the first (post-dose 1) and the second vaccination (post-dose 2). The levels of anti-RBD IgG and neutralizing antibodies increased significantly from baseline through post-dose 1 to post-dose 2 in all three groups. At the post-dose 1, the anti-RBD IgG and neutralizing antibody levels were significantly lower in cancer patients than in healthy controls. However, by post-dose 2, the seropositivity of anti-RBD IgG and neutralizing antibodies uniformly reached 100% across all groups, with no significant disparity in antibody levels among the three groups. Moreover, the antibody titers were not significantly different between patients with a vaccine and chemotherapy interval of more than 14 days or those with less than 14 days. This study demonstrated that after second doses of mRNA COVID-19 vaccines, humoral immune responses in patients receiving chemotherapy were comparable to those of healthy controls, regardless of whether the purpose of the anti-cancer treatment was palliative or adjuvant. Furthermore, the timing of vaccination did not affect the level of humoral immunity after the second vaccination.

While the guidelines for adjuvant chemotherapy (AC) for colon cancer are relatively standardized, those for early rectal cancer are still lacking. We therefore evaluated the role of AC in clinical stage II rectal cancer treatment after preoperative chemoradiotherapy (CRT). Patients diagnosed with early rectal cancer (defined by clinical stage T3/4, N0) who completed CRT followed by surgery were enrolled in this retrospective study. To evaluate the role of AC, we analyzed the risk of recurrence and survival based on clinicopathologic parameters and adjuvant chemotherapy. Of the 112 patients, 11 patients (9.8%) experienced recurrence and five patients (4.8%) died. In a multivariate analysis, circumferential resection margin involvement (CRM+) on magnetic resonance imaging at diagnosis, CRM involvement following neoadjuvant therapy (ypCRM+), tumor regression grade (≤G1) and no-AC were considered poor prognostic factors for recurrence free survival (RFS). In addition, ypCRM+ and no-AC were associated with poor overall survival (OS) in the multivariate analysis. AC including 5-FU monotherapy demonstrated the benefits of reduced recurrence and prolonged survival in clinical stage II rectal cancer, even in pathologic stage following neoadjuvant therapy (ypStage) 0-I. Further prospective studies are needed to verify the benefit of each regimen of AC and the development of a method that can accurately predict CRM status before surgery, and a vigorous treatment that can induce CRM non-involvement (CRM−) should be considered even in early stages of rectal cancer.

Cholesterol (CL) is required for various biomolecular production processes, including those of cell membrane components. Therefore, to meet these needs, CL is converted into various derivatives. Among these derivatives is cholesterol sulfate (CS), a naturally produced CL derivative by the sulfotransferase family 2B1 (SULT2B1), which is widely present in human plasma. CS is involved in cell membrane stabilization, blood clotting, keratinocyte differentiation, and TCR nanocluster deformation. This study shows that treatment of T cells with CS resulted in the decreased surface expression of some surface T-cell proteins and reduced IL-2 release. Furthermore, T cells treated with CS significantly reduced lipid raft contents and membrane CLs. Surprisingly, using the electron microscope, we also observed that CS led to the disruption of T-cell microvilli, releasing small microvilli particles containing TCRs and other microvillar proteins. However, in vivo, T cells with CS showed aberrant migration to high endothelial venules and limited infiltrating splenic T-cell zones compared with the untreated T cells. Additionally, we observed significant alleviation of atopic dermatitis in mice injected with CS in the animal model. Based on these results, we conclude that CS is an immunosuppressive natural lipid that impairs TCR signaling by disrupting microvillar function in T cells, suggesting its usefulness as a therapeutic agent for alleviating T-cellmediated hypersensitivity and a potential target for treating autoimmune diseases.

Background and Objectives: Airway reconstruction surgery in children is still challenging, especially in cases of combined subglottic and posterior glottic stenosis (PGS). The aim of this study was to review the underlying reasons of failure in open airway reconstruction surgeries performed for children with combined subglottic and PGS.Subjects and Method We reviewed medical records of seven children who received more than two open airway reconstruction surgeries to finally achieve and maintain decannulation status for more than one year. Twenty-two reconstructive surgeries were performed and they consisted of 19 laryngotracheal reconstruction (LTR), 2 cricotracheal resection with end-toend anastomosis (CTR) and one extended CTR. For each patient, the following potential causes of failure were evaluated; preoperative evaluation (PE), type of reconstruction (TR), single vs. double staging (SDS), type of stent (TS), and perioperative optimization (PO). Results: The median age of patients at the time of surgery was 32 months (range, 4-64 months). Successful decannulation was achieved after the median open surgery of three (range, 2-5 times for each patient). Recognized causes of failure were as follows: 8 insufficient PE, 10 inadequate TR, 3 improper SDS, 8 ill-chosen TS, and 2 inappropriate PO. Conclusion PE of dynamic airway is important, especially vocal fold mobility and tracheomalacia. Types of reconstruction should be carefully decided after full consideration of potential causes of failure, and adequate laryngotracheal stent is essential.

Background/Aims: Despite the increasing need for geriatric assessment prior to chemotherapy, the method for this assessment remains inadequate for older cancer patients. We aimed to propose a simple assessment method to predict the performance of adjuvant chemotherapy in older patients after colon cancer surgery. Methods: This prospective study included patients over 65 years of age who were scheduled for adjuvant chemotherapy after colon cancer surgery. Before initiating chemotherapy, their functional status was assessed on the basis of activities of daily living (ADL)/instrumental activities of daily living (IADL). These parameters were analyzed with clinical characteristics and the patterns of adjuvant chemotherapy. The focus was on the completion rate of adjuvant chemotherapy. Results: A total of 89 patients with a median age of 72 years were analyzed. Among them, 54 (61%) were non-impaired and 35 (39%) were impaired regarding their ADL/IADL classification. Low body mass index and impairment of ADL/IADLs were significantly associated with chemotherapy interruption. Among toxicities, fatigue and hand-foot syndrome were independent prognostic factors for chemotherapy interruption. Impairments of ADL/IADL were significantly associated with fatigue regardless of age. Based on age and ADL/IADL stratification, younger patients (≤ 72 years) and/or those who were ADL/IADL non-impaired were significantly more likely to complete adjuvant chemotherapy than older patients (> 72 years) and ADL/IADL impaired patients (p = 0.038). This was regardless of the chemotherapy regimen. Conclusions Functional assessment using ADL/IADL is a convenient method to predict chemotherapy toxicity and performance. These results suggested that routine screening for ADL/IADLs could guide appropriate patient selection for the completion of adjuvant chemotherapy and predict expected outcomes.

Extra-pulmonary neuroendocrine carcinoma is a rare and aggressive cancer. Although several biological and histological markers have been suggested as prognostic factors for this cancer, the prognostic importance of systemic inflammatory markers, including the neutrophil-lymphocyte ratio and platelet-lymphocyte ratio, is unclear. This study aimed to evaluate the association between systemic inflammatory markers and the prognosis of extra-pulmonary neuroendocrine carcinoma. We retrospectively analyzed the clinical data of 85 patients with unresectable or metastatic extra-pulmonary neuroendocrine carcinoma who received platinum-based chemotherapy as first-line chemotherapy from August 2007 to November 2019. We used time-dependent receiver operating characteristic curve analysis to determine the cut-off values. The cut-off values for the neutrophil-lymphocyte ratio and platelet-lymphocyte ratio were 3.0 and 158.5, respectively. There was no significant difference in the Eastern Cooperative Oncology Group performance status score, Ki-67 index, or response to chemotherapy between groups. The high neutrophil-lymphocyte ratio group showed significantly worse overall survival (high vs. low, median 11.1 vs. 21.0 months, log-rank p=0.004) and shorter median progression-free survival, but the latter was not statistically significant. The high platelet-lymphocyte ratio group also showed significantly worse progression-free survival and overall survival than the low platelet-lymphocyte ratio group (high vs. low:median 5.6 vs. 9.8 months, log-rank p=0.047 and median 13.8 vs. 21.0 months, log-rank p=0.013, respectively). In multivariable analysis, a high neutrophil-lymphocyte ratio was an independent prognostic factor for overall survival. The neutrophil-lymphocyte ratio is a potent and readily available prognostic factor for extra-pulmonary neuroendocrine carcinoma.

Purpose: This study aimed to identify patients who would benefit from third and subsequent lines of chemotherapy in recurrent epithelial ovarian cancer (EOC). Materials and Methods: Recurrent EOC patients who received third, fourth, or fifth-line palliative chemotherapy were retrospectively analyzed. Patients’ survival outcomes were assessed according to chemotherapy lines. Based on the best objective response, patients were divided into good-response (stable disease or better) and poor response (progressive disease or those who died before response assessment) groups. Survival outcomes were compared between the two groups, and factors associated with chemotherapy responses were investigated. Results: A total of 189 patients were evaluated. Ninety-four and 95 patients were identified as good and poor response group respectively, during the study period of 2008 to 2021. The poor response group showed significantly worse progression-free survival (median, 2.1 months vs. 9.7 months; p < 0.001) and overall survival (median, 5.0 months vs. 22.9 months; p < 0.001) compared with the good response group. In multivariate analysis adjusting for clinicopathologic factors, short treatment-free interval (TFI) (hazard ratio [HR], 5.557; 95% confidence interval [CI], 2.403 to 12.850), platinum-resistant EOC (HR, 2.367; 95% CI, 1.017 to 5.510), and non-serous/endometrioid histologic type (HR, 5.045; 95% CI, 1.152 to 22.088) were identified as independent risk factors for poor response. There was no difference in serious adverse events between good and poor response groups (p=0.167). Conclusion Third and subsequent lines of chemotherapy could be carefully considered for palliative purposes in recurrent EOC patients with serous or endometrioid histology, initial platinum sensitivity, and long TFIs from the previous chemotherapy regimen.

This study aimed to investigate the frequency of dental visits after coronavirus disease 2019 (COVID-19) in children and adolescents in comparison to that of adults. The data on the number of dental visits on the basis of different classification and treatment codes for all the age groups were provided by the Health Insurance Review and Assessment Service from January 2017 to December 2020. To reduce the impact of the population change, dental visits per 1000 people was used. After the start of the pandemic, dental visits per 1000 people decreased in all age groups when analyzed for the diseases of pulp and periapical tissues classification code and dental visits per 1000 people decreased over 5 years age groups when analyzed for the pulp treatment code. Regarding the restorative treatment code, visits in the 0 - 19 years age group decreased after the pandemic. Based on the comparison of the number of confirmed COVID-19 cases to that of monthly dental visits by treatment codes, the change rate of pulp and restorative treatments gradually decreased after the waves of the pandemic in February and August 2020 in Korea. Furthermore, dental visits per 1000 people for gingivitis and periodontal disease classification code increased after the pandemic in all age groups. The rate of decrease in dental visits per 1000 people for restorative treatments in children and adolescents was higher than that in adults. The rate of decrease in the number of dental visits for multi-visit pulp treatments showed a rapid decrease as compared to that of 1-visit pulp treatments after the pandemic. This study identified changes in the number of dental visits of children and adolescents after COVID-19 transmission in comparison to that observed in adults.

Chemotherapeutic drugs can cause cardiac toxicities such as cardiomyopathy, arrhythmia, and cardiovascular disease. The well-known side effects of cisplatin are nephrotoxicity, nausea, vomiting, and electrolyte imbalance. Cardiotoxicity induced by cisplatin is rare, and its pathophysiology is unknown. Here, we present two cases of complete and high-degree atrioventricular (AV) block that occurred during cisplatin-based chemotherapy and required pacemaker placement. A 64-year-old woman and a 75-year-old man, who had no underlying heart disease, developed dyspnea without chest pain and bradycardia during cisplatin-based chemotherapy. However, there were no significant differences in their serum electrolyte levels, cardiac enzyme levels, and echocardiography results before and after drug administration. The ECGs were confirmed with complete AV block and highdegree AV block, which requiring pacemaker placement. We assume that cisplatin directly caused the complete, high-degree AV block, which required a pacemaker placement in our cases. In such cases, a cumulative dose of cisplatin over 240 mg/m 2 is a risk factor for early symptoms of AV block. If patients complain of dyspnea without chest pain during cisplatin-based chemotherapy, arrhythmic complications should be considered. This information may be helpful for clinicians treating patients with cisplatin chemotherapy.