Association between Atherosclerosis and High-Risk Colorectal Adenomas based on Cardio-Ankle Vascular Index and Ankle-Brachial Index.

Background/Aims: Colorectal adenomas are precancerous lesions that may lead to colorectal cancer. Recent studies have shown that colorectal adenomas are associated with atherosclerosis. The cardio-ankle vascular index (CAVI) and ankle-brachial index (ABI) are noninvasive methods for evaluating atherosclerosis. This study examined the association between atherosclerosis and high-risk colorectal adenomas based on the CAVI and ABI. Methods: The data of patients aged ≥50 years who had a colonoscopy and CAVI and ABI measurements from August 2015 to December 2021 at the Kangwon National University Hospital were analyzed retrospectively. After the colonoscopy, subjects were divided into no, overall, and high-risk (size ≥1 cm, high-grade dysplasia or villous adenoma, three or more adenomas) adenoma groups based on the pathology findings. The data were subjected to univariate and multivariate logistic regression analyses. Results: Among the 1,164 subjects, adenomas and high-risk adenomas were found in 613 (52.6%) and 118 (10.1%) patients, respectively. The rate of positive ABI (<0.9) and positive CAVI (≥9.0) were significantly higher in the high-risk adenoma group (22.0% and 55.9%) than in the no adenoma (12.3% and 39.6%) and the overall adenoma group (15.7% and 44.0%) (p=0.008 and p=0.006, respectively). Multivariate analysis revealed a positive CAVI and smoking status to be significantly associated with high-risk adenoma with an odds ratio of 1.595 (95% confidence interval 1.055-2.410, p=0.027) and 1.579 (1.072-2.324, p=0.021), respectively. Conclusions: In this study, a significant correlation between positive CAVI and high-risk adenomas was observed. Therefore, CAVI may be a significant predictor for high-risk colorectal adenoma.

Practice guidelines for managing extrahepatic biliary tract cancers.

Backgrounds/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.

Diagnosis and Treatment of Perihilar Cholangiocarcinoma: A National Survey from the Korean Pancreatobiliary Association.

Background/Aims: Based on their anatomy, cholangiocarcinomas (CCAs) are classified into intrahepatic, hilar, and distal CCAs. Although the diagnosis and treatment of each type of CCA are thought to be different, real-world data studies on the current practice are limited. Therefore, this study was designed to capture the current practice of diagnosing and treating perihilar CCA in Korea. Methods: We conducted a survey using an online platform. The questionnaire consisted of 18 questions designed to evaluate the current practice of diagnosing and treating perihilar CCA in Korea. The targets of this survey were biliary endoscopists who are members of the Korean Pancreatobiliary Association. Results: In total, 119 biliary endoscopists completed the survey. Of the respondents, 89.9% thought that the use of the International Classification of Diseases, 11th Revision (ICD-11) system is necessary to classify CCA. Approximately half of the respondents would recommend surgery or chemotherapy until patients were 80 years of age. For the pathological diagnosis of CCA, endoscopic retrograde cholangiopancreatography with biopsy was the most preferred modality. Routine preoperative biliary drainage was performed by 44.5% of the respondents. For operable CCAs, 64.7% of the respondents preferred endoscopic biliary drainage using plastic stents. For palliative biliary drainage, 69.7% of the respondents used plastic stents. For palliative endoscopic biliary drainage using metal stents, 63% of the respondents preferred the stent-in-stent method. Conclusions: A new coding system using the ICD-11 is needed for classifying CCAs. Guidelines for diagnosing and treating CCA based on the clinical situation in Korea are needed.

A population-based cohort study on risk factors for acute pancreatitis: A comparison by age group.

BACKGROUND: /objectives: Acute pancreatitis (AP) is an acute inflammatory disorder that can occur in all age groups. The risk of AP has been shown to increase with age. However, no study has compared risk factors for AP according to age group yet. Thus, the aim of this study was to perform such comparison. METHODS: Clinical data from individuals 20 years of age and older who received a health examination arranged by the Korean national health insurance program in 2009 (n = 4,238,822) were used. First-attack AP was identified using claims data from baseline to December 2018. Incidence and risk factors of AP were analyzed for young (20-39 years old), middle-aged (40-64 years old), and old (over 65 years old) groups. RESULTS: Incidences of AP in young, middle-aged, and old groups were 16.30, 27.85, and 57.19 per 100,000 person-years, respectively. Smoking, alcohol drinking, diabetes, gallstone, and chronic pancreatitis were associated with increased risk of AP in all age groups. Meanwhile, male, older age, and higher waist circumference were associated with increased risk of AP in middle-aged and old groups. In young and middle-aged groups, risk of AP was increased in the presence of hypertension and dyslipidemia. However, high income was associated with decreased risk of AP in these groups. CONCLUSIONS: In this population-based cohort study, incidences and risk factors for AP differed according to age group. Thus, a tailored strategy might be needed to prevent AP according to age group.

The association between smoking, changes in smoking behavior, and acute pancreatitis: A population-based cohort study in Korea.

BACKGROUND AND AIMS: In the Asian population, existing studies regarding the association between smoking and acute pancreatitis are few in number. The aim of this study was to investigate the incidence of acute pancreatitis according to smoking habits and smoking habit changes of the Korean population. METHODS: We used clinical data from individuals (aged 20 years or older) who received health examinations arranged by the Korean National Health Insurance Service in 2009 (n = 4 238 822) or in 2009 and 2011 (n = 2 617 306). The incidence of acute pancreatitis was analyzed according to smoking status or smoking habit change reported by individuals during their health examination. Newly diagnosed acute pancreatitis was identified using claims data from baseline to the date of diagnosis or until December 31, 2018. RESULTS: The risk of acute pancreatitis was significantly higher in current smokers compared with never-smokers regardless of age or sex. The adjusted hazard ratio (HR) of acute pancreatitis in current smokers increased according to the amount of smoking (HR 1.28; 95% confidence interval [CI], 1.12-1.45 in <10 cigarettes/day, HR 1.4; CI, 1.3-1.52 in 10-19 cigarettes/day, HR 1.66; CI, 1.55-1.78 in ≥20 cigarettes/day). The adjusted HR of acute pancreatitis in continuous smokers was 1.66 (CI, 1.53-1.8) compared with never-smokers and was higher than smokers who quit smoking (HR 1.34; CI, 1.17-1.54). CONCLUSIONS: In this Korean population-based cohort study, smoking increased the incidence of acute pancreatitis in a dose-dependent manner, and smoking cessation helped decrease the incidence of acute pancreatitis.

Endoscopist-Driven Sedation Practices in South Korea: Re-evaluation Considering the Nationwide Survey in 2019.

Background/Aims: This study aimed to determine changes in endoscopist-driven sedation practices 5 years after the first nationwide survey in 2014 by the Korean Society of Gastrointestinal Endoscopy (KSGE). Methods: A 59-item survey covering current practices was electronically mailed to all members of the KSGE in 2019. Results: In total, 955 (12.8%) out of 7,486 questionnaires were returned. A total of 738 (77.7%) out of 955 respondents attended dedicated sedation education programs. The American Society of Anesthesiologists class was recorded by 464 (51.2%) out of 907 respondents. The recording rate was higher in respondents who completed sedation education (p=0.014) and worked in general or tertiary hospitals (p<0.001). Compared to that reported in the previous survey, the reported use of propofol was higher in 2019. The respondents had higher satisfaction scores for propofol-based sedation compared with midazolam monotherapy (p<0.001). The rates of oxygen supplementation (p<0.001) and oxygen saturation level monitoring (p<0.001) during sedative endoscopy were higher in 2019 than in the previous survey. A total of 876 (98.4%) out of 890 respondents reported a separate recovery bay, and 615 (70.5%) out of 872 respondents reported that personnel were assigned solely to the recovery bay. Conclusions: Endoscopist-driven sedation and monitoring practices in 2019 were significantly different than those in 2014. The respondents favored propofol-based sedation and utilized oxygen supplementation and monitoring of O2 saturation more frequently in 2019 than in 2014.

2021 Korean Society of Gastrointestinal Endoscopy Clinical Practice Guidelines for Endoscopic Sedation.

Sedation can resolve anxiety and fear in patients undergoing endoscopy. The use of sedatives has increased in Korea. Appropriate sedation is a state in which the patient feels subjectively comfortable while maintaining the airway reflex for stable spontaneous breathing. The patient should maintain a state of consciousness to the extent that he or she can cooperate with the needs of the medical staff. Despite its benefits, endoscopic sedation has been associated with cardiopulmonary complications. Such cardiopulmonary complications are usually temporary, and most patients recover without sequelae. However, these events may progress to serious complications, such as cardiovascular collapse. Therefore, it is essential to screen high-risk patients before sedation and reduce complications by meticulous monitoring. Additionally, physicians should be familiar with the management of emergencies. The first Korean clinical practice guideline for endoscopic sedation was developed based on previous worldwide guidelines for endoscopic sedation using an adaptation process. The guideline consists of nine recommendations based on a critical review of currently available data and expert consensus when the guideline was drafted. These guidelines should provide clinicians, nurses, medical school students, and policy makers with information on how to perform endoscopic sedation with minimal risk.

[2021 Korean Society of Gastrointestinal Endoscopy Clinical Practice Guidelines for Endoscopic Sedation].

Sedation can resolve anxiety and fear in patients undergoing endoscopy. The use of sedatives has increased in Korea. Appropriate sedation is a state in which the patient feels subjectively comfortable while maintaining the airway reflex for stable spontaneous breathing. The patient should maintain a state of consciousness to the extent that he or she can cooperate with the needs of the medical staff. Despite its benefits, endoscopic sedation has been associated with cardiopulmonary complications. Cardiopulmonary complications are usually temporary. Most patients recover without sequelae. However, they may progress to serious complications, such as cardiovascular collapse. Therefore, it is essential to screen high-risk patients before sedation and reduce complications by meticulous monitoring. Additionally, physicians should be familiar with the management of emergencies. The first Korean clinical practice guideline for endoscopic sedation was developed based on previous worldwide guidelines for endoscopic sedation using an adaptation process. The guideline consists of nine recommendations based on a critical review of currently available data and expert consensus when the guideline was drafted. These guidelines should provide clinicians, nurses, medical school students, and policy makers with information on how to perform endoscopic sedation with minimal risk.

Prostate Cancer Presenting with Pruritus and Cholestasis.

Jaundice is a rare symptom of the paraneoplastic syndrome associated with prostate cancer. We report a case of metastatic prostate cancer that presented as jaundice. There was an absence of biliary obstruction and hepatic metastasis; therefore, the paraneoplastic syndrome was suggested as the etiology of cholestasis. Jaundice improved with the treatment of prostate cancer. In the literature, interleukin-6 has been suggested to be associated with paraneoplastic syndrome.

Cholecystoduodenal fistula presenting with upper gastrointestinal bleeding: A case report.

BACKGROUND: Cholecystoduodenal fistula is a rare complication of cholelithiasis. Symptoms are usually non-specific and often indistinguishable from those of etiologic diseases, but it rarely presents as severe gastrointestinal bleeding. Bleeding associated with cholecystoduodenal fistula usually requires surgery because significant bleeding from the cystic artery is unlikely to be resolved by conservative management or endoscopic hemostasis. CASE SUMMARY: We report a case of cholecystoduodenal fistula that presented with hematemesis which was diagnosed by endoscopy and computed tomography. Endoscopic hemostasis could not be achieved, but surgical treatment was successful. Additionally, we have presented a literature review. CONCLUSION: Cholecystoduodenal fistula should be considered as differential diagnosis when a patient with history of gallstone disease presents with gastrointestinal bleeding.

Association between interstitial cells of Cajal and anti-vinculin antibody in human stomach.

Interstitial cells of Cajal (ICC) are known as the pacemaker cells of gastrointestinal tract, and it has been reported that acute gastroenteritis induces intestinal dysmotility through antibody to vinculin, a cytoskeletal protein in gut, resulting in small intestinal bacterial overgrowth, so that anti-vinculin antibody can be used as a biomarker for irritable bowel syndrome. This study aimed to determine correlation between serum anti-vinculin antibody and ICC density in human stomach. Gastric specimens from 45 patients with gastric cancer who received gastric surgery at Kangwon National University Hospital from 2013 to 2017 were used. ICC in inner circular muscle, and myenteric plexus were counted. Corresponding patient's blood samples were used to determine the amount of anti-vinculin antibody by enzyme-linked immunosorbent assay. Analysis was done to determine correlation between anti-vinculin antibody and ICC numbers. Patients with elevated anti-vinculin antibody titer (above median value) had significantly lower number of ICC in inner circular muscle (71.0 vs. 240.5, p = 0.047), and myenteric plexus (12.0 vs. 68.5, p < 0.01) compared to patients with lower anti-vinculin antibody titer. Level of serum anti-vinculin antibody correlated significantly with density of ICC in myenteric plexus (r = -0.379, p = 0.01; Spearman correlation). Increased level of circulating anti-vinculin antibody was significantly correlated with decreased density of ICC in myenteric plexus of human stomach.

Recent 5-Year Trend of Endoscopic Retrograde Cholangiography in Korea Using National Health Insurance Review and Assessment Service Open Data.

Background/Aims: The utilization of endoscopic retrograde cholangiopancreatography (ERCP) is variable and largely dependent on a patient's age, sex, and region. Herein we analyzed the publicly available Health Insurance Review and Assessment (HIRA) database with the aim of understanding the current status and trend of ERCP use in Korea. Methods: Between 2013 and 2017, information regarding ERCP was acquired from the HIRA database using the procedural codes of the Korean Standard Classification of Disease. We analyzed the annual number of patients according to age in 10- year increments, sex, type of medical institution, and administrative division. Results: The total number of patients and number of patients undergoing ERCP per 100,000 people increased from 40,516 and 78.6 in 2013 to 47,027 and 91.3 in 2017, respectively those aged 70 years accounted for the highest number, and the increase was the most prominent in those aged 80 years or older. Men underwent more ERCPs than women, except in younger patients (<40 years). Most ERCPs were performed at tertiary and general hospitals; however, the ratios between the two types of institutions were different according to the procedure. There were different patterns of patients associated with each procedure according to the administrative division. Therapeutic ERCP was performed more frequently than diagnostic ERCP. Conclusions: Most procedures in Korea were therapeutic, and the increase in patients was most prominent in those aged 80 years or older. The utilization of ERCP increased markedly and varied depending on age, sex, type of medical institution, and region.

Pancreatitis, Panniculitis, and Polyarthritis Syndrome Simulating Cellulitis and Gouty Arthritis.

Pancreatitis, panniculitis, and polyarthritis (PPP) syndrome is a rare but critical disease with a high mortality rate. The diagnostic dilemma of PPP syndrome is the fact that symptoms occur unexpectedly. A 48-year-old man presented with fever and painful swelling of the left foot that was initially mistaken for cellulitis and gouty arthritis. The diagnosis of PPP syndrome was made based on the abdominal CT findings and elevated pancreatic enzyme levels, lobular panniculitis with ghost cells on a skin biopsy, and polyarthritis on a bone scan. The pancreatitis and panniculitis disappeared spontaneously over time, but the polyarthritis followed its own course despite the use of anti-inflammatory agents. In addition to this case, 30 cases of PPP syndrome in the English literature were reviewed. Most of the patients had initial symptoms other than abdominal pain, leading to misdiagnosis. About one-third of them were finally diagnosed with a pancreatic tumor, of which pancreatic acinar cell carcinoma was the most dominant. They showed a mortality rate of 32.3%, associated mainly with the pancreatic malignancy. Therefore, PPP syndrome should be considered when cutaneous or osteoarticular manifestations occur in patients with pancreatitis. Active investigation and continued observations are needed for patients suspected of PPP syndrome.

Colonic Diffuse Large B-cell Lymphoma Hidden in Actinomycosis.

Actinomycosis can mask malignant diseases. This paper reports a case of colonic diffuse large B-cell lymphoma (DLBCL), which was misdiagnosed as abdominal actinomycosis. A 76-year-old woman presented with right flank pain and weight loss. Abdominal CT and colonoscopy revealed a huge ascending colon mass. Despite the initial impression of a malignancy, a colonoscopic biopsy revealed no malignant cells, but sulfur granules and a filamentous organism suggesting actinomycosis. Intravenous penicillin G was administered under the impression of abdominal actinomycosis but her condition deteriorated rapidly. Follow up CT showed markedly increased colon mass and new multiple nodular lesions around the ascending colon. Sono-guided percutaneous biopsy of the nodular lesion was performed. The pathological result was DLBCL. The patient was scheduled to undergo chemotherapy but the patient expired due to cancer progression. The diagnosis of gastrointestinal infiltrating tumors is often difficult because a superficial biopsy usually does not provide a confirmative diagnosis. This case highlights the difficulty in making a correct diagnosis of lymphoma due to the concomitant actinomycosis. Malignant conditions must be considered in cases of actinomycosis with no response to antimicrobial therapy.

Pancreatic Metastasis from Adenocarcinoma of the Uterine Cervix.

Pancreatic metastasis from cervical cancer is extremely rare. We report a case of metastatic adenocarcinoma of the pancreas from uterine cervical cancer. A 70-year-old woman was referred because of a pancreatic mass detected by CT. She had been diagnosed with uterine cervical adenocarcinoma 20 months previously. After concurrent chemoradiotherapy, CT showed no evidence of the cervical mass, and follow-up showed no evidence of recurrence. Endoscopic ultrasound-guided fine needle aspiration biopsy of the pancreatic mass resulted in a diagnosis of metastatic adenocarcinoma from uterine cervix.

Validation of modified fibrosis-4 index for predicting hepatocellular carcinoma in patients with compensated alcoholic liver cirrhosis.

Recently, modified fibrosis-4 index (mFIB-4) and the easy liver fibrosis test (eLIFT) were developed for predicting liver fibrosis in chronic liver disease patients. We evaluated whether the 2 tests can predict hepatocellular carcinoma (HCC) risk in alcoholic liver cirrhosis (ALC) patients.A retrospective cohort of 924 ALC patients was assessed for HCC development. Four non-invasive serum biomarkers, mFIB-4, the eLIFT score, fibrosis-4 index (FIB-4), and aspartate aminotransferase to platelet ratio index (APRI) were tested using time-dependent analysis of areas under receiver operating characteristic curve (AUROC), DeLong, and log-rank tests.During a median 4.8 years of follow-up, HCC occurred in 83 patients (9.0%). For predicting HCC development at 3 years, the mFIB-4 showed a significantly higher AUROC than APRI and eLIFT scores (0.71 vs 0.61 and 0.56, respectively, all P < .05). The AUROCs of the mFIB-4 for HCC development were not significantly different from those of the FIB-4. According to the mFIB-4, the risk of HCC development was significantly stratified by low index (≤4)/high index (>4) (P < .001 by log-rank test).The mFIB-4 showed better predictability of HCC development than APRI and eLIFT scores, and significantly stratified HCC risk in Asian ALC patients.

Effects of Saline Irrigation of the Bile Duct to Reduce the Rate of Residual Common Bile Duct Stones: A Multicenter, Prospective, Randomized Study.

OBJECTIVES: In clinical practice, recurrent cholangitis due to residual common bile duct (CBD) stone occurs frequently even after endoscopic stone removal. This study aimed to determine whether preventive saline irrigation of the bile duct (PSIB) after endoscopic removal of CBD stones would decrease the residual CBD stones. METHODS: In this multicenter, prospective, randomized study, patients who received endoscopic retrograde cholangiopancreatography for removal of CBD stone were randomized to either receiving PSIB after stone removal (PSIB group) or not receiving PSIB (non-PSIB group). Patients were prospectively followed up and the presence of residual CBD stones was evaluated within 6 months after endoscopic stone removal. RESULTS: A total of 148 patients were enrolled and completed follow-up (73 in PSIB group and 75 in non-PSIB group). The two groups were similar with regard to baseline characteristics. Residual CBD stones were detected in 22 patients (14.9%). The incidences of residual CBD stones were 6.8% in PSIB group and 22.7% in non-PSIB group (P=0.010). Multivariate analysis revealed that the performance of PSIB and the presence of only a single-CBD stone were the significant factors for the decrease of the occurrence of the residual CBD stones. Although, procedure time was slightly longer in PSIB group (22.0 vs 19.2 min, P=0.037), no significant difference was observed in the procedure-related complications between the two groups. CONCLUSIONS: PSIB could reduce the residual CBD stones without increasing complications. Considering the efficacy and safety, routine PSIB after endoscopic CBD stone removal seems to be preferred (ClinicalTrials.gov identifier: NCT01425177).

[Pancreatic Neuroendocrine Tumor Presenting as Acute Pancreatitis].

We report a case of acute pancreatitis secondary to pancreatic neuroendocrine tumor. A 46-year old man presented with upper abdominal pain. The serum amylase and lipase were elevated. Abdominal computed tomography (CT) and magnetic resonance cholangiopancreatography revealed a 1.7 cm sized mass at the pancreas body with a dilatation of the upstream pancreatic duct and mild infiltrations of peripancreatic fat. An endoscopic ultrasound-guided fine needle biopsy was performed for the pancreatic mass, but only necrotic tissue was observed on the pathologic examination. A chest and neck CT scan revealed anterior mediastinal, paratracheal, and cervical lymph node enlargement, which were indicative of metastasis. An ultrasound-guided core needle biopsy was performed for the enlarged neck lymph node, and pathologic examination revealed a metastatic poorly differentiated carcinoma. Immunohistochemical analysis showed positive staining for synaptophysin, chromogranin A, and CD 56, indicative of a neuroendocrine carcinoma.

Additional K-ras mutation analysis and Plectin-1 staining improve the diagnostic accuracy of pancreatic solid mass in EUS-guided fine needle aspiration.

BACKGROUND: One of the major genetic alterations in pancreatic ductal adenocarcinoma (PDAC) is the point mutation of K-ras gene. Plectin-1 was also recently identified as PDAC specific biomarker. The aim of this study was to investigate the improvement of diagnostic accuracy of endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) by using additional K-ras mutation analysis and Plectin-1 staining in patients with pancreatic mass. METHODS: A total of 85 study patients with pancreatic mass underwent EUS-FNA and the final diagnoses were as follows; PDACs: 70 patients, pancreas neuroendocrine tumor: 4, metastasis to pancreas: 5, autoimmune pancreatitis: 3, chronic pancreatitis: 1, tuberculous lymphadenitis: 1, pseudocyst: 1. RESULTS: Sensitivity, specificity and accuracy of pathologic diagnosis in EUS-FNA specimen were 81%, 80% and 79% accordingly. When we combine K-ras gene mutation analysis with histological assessment, we could get the following results for sensitivity, specificity and accuracy; cytology and K-ras mutation analysis: 93%, 87%, and 92%, cytology, K-ras mutation analysis, and Plectin-1 staining: 96%, 93%, and 95%. CONCLUSIONS: Triple combinations of the techniques; cytology, K-ras gene mutation analysis, Plectin-1 staining could increase accuracy in diagnosis of PDACs. Further investigation of using minimal specimens from EUS-FNA may give us insight to understand the biological behavior of PDAC.

Endoscopic bilateral stent-in-stent placement for malignant hilar obstruction using a large cell type stent.

BACKGROUND: Bilateral stent-in-stent (SIS) self-expandable metal stent placement is technically challenging for palliation of unresectable malignant hilar obstruction. In the SIS technique, the uniform large cell type biliary stent facilitates contralateral stent deployment through the mesh of the first metallic stent. This study aimed to assess the technical success and clinical effectiveness of this technique with a uniform large cell type biliary stent. METHODS: Thirty-one patients who underwent bilateral SIS placement using a large cell type stent were reviewed retrospectively. All patients showed malignant hilar obstruction (Bismuth types II, III, IV) with different etiologies. RESULTS: Sixteen (51.6%) patients were male. The mean age of the patients was 67.0+/-14.0 years. Most patients were diagnosed as having hilar cholangiocarcinoma (58.1%) and gallbladder cancer (29.0%). Technical success rate was 83.9%. Success was achieved more frequently in patients without masses obstructing the biliary confluence (MOC) than those with MOC (95.2% vs 60.0%, P=0.03). Functional success rate was 77.4%. Complications occurred in 29.0% of the patients. These tended to occur more frequently in patients with MOC (50.0% vs 19.0%, P=0.11). Median time to recurrent biliary obstruction was 188 days and median survival was 175 days. CONCLUSIONS: The large cell type stent can be used efficiently for bilateral SIS placement in malignant hilar obstruction. However, the risk of technical failure increases in patients with MOC, and caution is needed to prevent complications for these patients.