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.

Background/Aims: Daratumumab has shown an encouraging antitumor effect in patients with multiple myeloma (MM), and was known to alter the immune properties by off-targeting immunosuppressive cells. Here, we aimed to evaluate the change in absolute lymphocyte count (ALC) as a surrogate marker for predicting survival outcomes of patients treated with daratumumab. Methods: Between 2018 and 2021, the medical records of patients with relapsed/refractory MM (RRMM) treated with daratumumab monotherapy at 10 centers in South Korea were reviewed. We collected the ALC data at pre-infusion (D0), day 2 after the first infusion (D2), and prior to the third cycle of daratumumab therapy (D56). Results: Fifty patients who were administered at least two cycles of daratumumab were included. Overall response rate was 54.0% after two cycles of daratumumab treatment. On D2, almost all patients experienced a marked reduction in ALC. However, an increase in ALC on D56 (ALCD56) was observed in patients with non-progressive disease, whereas failure of ALC recovery was noted in those with progressive disease. Patients with ALCD56 > 700/μL (n = 39, 78.0%) had prolonged progression- free survival (PFS) and overall survival (OS) than those with ALCD56 ≤ 700/μL (median PFS: 5.8 months vs. 2.6 months, p = 0.025; median OS: 24.1 months vs. 6.1 months, p = 0.004). In addition, ALCD56 >700/μL was a significant favorable prognostic factor for PFS (hazard ratio [HR], 0.22; p = 0.003) and OS (HR, 0.23; p = 0.012). Conclusions Increase in ALC during daratumumab treatment was significantly associated with prolonged survival outcomes in patients with RRMM. The ALC value can predict clinical outcomes in patients treated with daratumumab.

Background/Aims: In ulcerative colitis (UC) patients, Escherichia coli Nissle 1917 (EcN) is equivalent to mesalazine for preventing disease relapse; however, evidence of the ability of EcN to increase health-related quality of life or induce remission remains scarce. We investigated the efficacy of EcN as an add-on therapy for UC. Methods: In this multicentre, double-blind, randomised, placebo-controlled study, a total of 133 UC patients were randomly assigned to receive either EcN or placebo once daily for 8 weeks. Inflammatory bowel disease questionnaire (IBDQ) scores (primary endpoint) and clinical remission and response rates (secondary endpoints) were compared (Clinical trial registration number: NCT04969679). Results: In total, 118 patients (EcN, 58; placebo, 60) completed the study. The number of patients reaching the primary endpoint did not differ between the EcN and placebo groups (30 [51.7%] vs. 31 [51.7%]; per-protocol analysis, p = 1.0; intention-to-treat analysis, p = 0.86). However, significantly fewer patients in the EcN group exhibited a decreased IBDQ score (1 [1.7%] vs. 8 [13.3%]; per-protocol analysis, p = 0.03; intention- to-treat analysis, p = 0.02). Moreover, a significantly higher number of patients in the EcN group displayed clinical response at 4 weeks (23 [39.7%] vs. 13 [21.7%], p = 0.04) and endoscopic remission at 8 weeks (26 [46.4%] vs. 16 [27.1%], p = 0.03). Conclusions Although the number of patients reaching the primary endpoint did not differ between the EcN and placebo groups, EcN was found to be safe and effective in preventing the exacerbation of IBDQ scores and achieving clinical responses and endoscopic remission in patients with mild-to-moderate UC.

Background/Aims: The protective effects of vitamin D and calcium on colorectal neoplasms are known. Bone mineral density (BMD) may be a reliable biomarker that reflects the long-term anticancer effect of vitamin D and calcium. This study aimed to evaluate the association between BMD and colorectal adenomas including high-risk adenoma. Methods: A multicenter, cross-sectional, case-control study was conducted among participants with average risk of colorectal cancer who underwent BMD and screening colonoscopy between 2015 and 2019. The main outcome was the detection of colorectal neoplasms. The variable under consideration was low BMD (osteopenia/osteoporosis). The logistic regression model included baseline demographics, components of metabolic syndrome, fatty liver disease status, and aspirin and multivitamin use. Results: A total of 2,109 subjects were enrolled. The mean age was 52.1±10.8 years and 42.6% were male. The adenoma detection rate was 43%. Colorectal adenoma and high-risk adenoma were both more prevalent in subjects with low BMD than those with normal BMD (48.2% vs 38.8% and 12.1% vs 9.1%). In the univariate analysis, old age, male sex, smoking, metabolic components, fatty liver, and osteoporosis were significantly associated with the risk of adenoma and high-risk adenoma. In the multivariate analysis, osteoporosis was independently associated with risk of colorectal adenoma (odds ratio [OR], 1.65; 95% confidence interval [CI], 1.11 to 2.46; p=0.014) and high-risk adenoma (OR, 1.94; 95% CI, 1.14 to 3.29; p=0.014). Conclusions Osteoporosis is an independent risk factor of colorectal adenoma and high-risk adenoma

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.

This study aimed to evaluate the antibacterial activities sustainability of antibacterial agents mixed with experimental fluoride varnish on hydroxyapatite disc against Streptococcus mutans (S. mutans). On the hydroxyapatite disc with 4.8 mm of diameter, 5 μL of 1 mM antibacterial agents mixed with experimental fluoride varnish were applied. Positive control and vehicle control were 10 μg/mL ampicillin and dimethyl sulfoxide (DMSO) mixed with fluoride varnish, respectively. The discs were stored in distilled water in a 37℃ shaking water bath at 120 rpm for 30 minutes, 4 hours, 1 day, 5 days, 20 days, and 30 days. Antibacterial activities were evaluated with the inhibition zone by the agar diffusion test. The antibacterial activities of all antibacterial agents were sustained for 30 days. Among them, Bakuchiol, Bavachromene, and Bavachalcone showed higher antibacterial activities for up to 30 days. The antibacterial agents when mixed in the experimental fluoride varnish with increased and prolonged antibacterial activities can be applied to prevent dental caries effectively.

This study aimed to evaluate the antibacterial activities sustainability of antibacterial agents mixed with experimental fluoride varnish on hydroxyapatite disc against Streptococcus mutans (S. mutans). On the hydroxyapatite disc with 4.8 mm of diameter, 5 μL of 1 mM antibacterial agents mixed with experimental fluoride varnish were applied. Positive control and vehicle control were 10 μg/mL ampicillin and dimethyl sulfoxide (DMSO) mixed with fluoride varnish, respectively. The discs were stored in distilled water in a 37℃ shaking water bath at 120 rpm for 30 minutes, 4 hours, 1 day, 5 days, 20 days, and 30 days. Antibacterial activities were evaluated with the inhibition zone by the agar diffusion test. The antibacterial activities of all antibacterial agents were sustained for 30 days. Among them, Bakuchiol, Bavachromene, and Bavachalcone showed higher antibacterial activities for up to 30 days. The antibacterial agents when mixed in the experimental fluoride varnish with increased and prolonged antibacterial activities can be applied to prevent dental caries effectively.

Purpose: The introduction of immune checkpoint inhibitors represents a major advance in the treatment of lung cancer, allowing sustained recovery in a significant proportion of patients. Nivolumab is a monoclonal anti–programmed death cell protein 1 antibody licensed for the treatment of locally advanced or metastatic non-small cell lung cancer (NSCLC) after prior chemotherapy. In this study, we describe the demographic and clinical outcomes of patients with advanced NSCLC treated with nivolumab in the Korean expanded access program. Materials and Methods: Previously treated patients with advanced non-squamous and squamous NSCLC patients received nivolumab at 3 mg/kg every 2 weeks up to 36 months. Efficacy data including investigator-assessed tumor response, progression data, survival, and safety data were collected. Results: Two hundred ninety-nine patients were treated across 36 Korean centers. The objective response rate and disease control rate were 18% and 49%, respectively; the median progression-free survival was 2.1 months (95% confidence interval [CI], 1.87 to 3.45), and the overall survival (OS) was 13.2 months (95% CI, 10.6 to 18.9). Patients with smoking history and patients who experienced immune-related adverse events showed a prolonged OS. Cox regression analysis identified smoking history, presence of immune-related adverse events as positive factors associated with OS, while liver metastasis was a negative factor associated with OS. The safety profile was generally comparable to previously reported data. Conclusion This real-world analysis supports the use of nivolumab for pretreated NSCLC patients, including those with an older age.