An atypical case of isolated immunoglobulin G4-related sclerosing cholangitis with a cholangiogram resembling primary sclerosing cholangitis.

An asymptomatic 77-year-old man with intrahepatic bile duct dilation was referred to our hospital. Cholangiography revealed alternations between strictures and dilated segments from the right and left hepatic ducts to the lower bile ducts, with findings of a pruned tree, beaded, shaggy appearance, and diverticulum-like outpouching. Histopathology revealed abundant immunoglobulin G4 (IgG4)-positive plasma cells (> 10 per high-power field) with an IgG4/IgG-positive cell ratio of 40-50%. After 2 weeks of steroid therapy, the cholangiography markedly improved. Because the cholangiographic findings resembled those of primary sclerosing cholangitis, steroid therapy proved useful in differentiating IgG4-related sclerosing cholangitis from primary sclerosing cholangitis.

Impact of sarcopenia on biliary drainage during neoadjuvant therapy for pancreatic cancer.

BACKGROUND/AIMS: Since the usefulness of neoadjuvant chemo(radiation) therapy (NAT) for pancreatic cancer has been demonstrated, recurrent biliary obstruction (RBO) in patients with pancreatic cancer with a fully covered self-expandable metal stent (FCSEMS) during NAT is expected to increase. This study investigated the impact of sarcopenia on RBO in this setting. METHODS: Patients were divided into normal and low skeletal muscle index (SMI) groups and retrospectively analyzed. Patient characteristics, overall survival, time to RBO (TRBO), stent-related adverse events, and postoperative complications were compared between the two groups. A Cox proportional hazard model was used to identify the risk factors for short TRBO. RESULTS: A few significant differences were observed in patient characteristics, overall survival, stent-related adverse events, and postoperative complications between 38 patients in the normal SMI group and 17 in the low SMI group. The median TRBO was not reached in the normal SMI group and was 112 days in the low SMI group (p=0.004). In multivariate analysis, low SMI was the only risk factor for short TRBO, with a hazard ratio of 5.707 (95% confidence interval, 1.148-28.381; p=0.033). CONCLUSION: Sarcopenia was identified as an independent risk factor for RBO in patients with pancreatic cancer with FCSEMS during NAT.

Outcomes of endoscopic papillectomy of ampullary carcinoma and factors affecting additional surgery.

BACKGROUND/PURPOSE: Data on the prognosis of endoscopic papillectomy (EP) for ampullary carcinoma (AC) is limited; therefore, we aimed to identify the factors associated with endoscopically controlled AC. METHODS: Between January 2003 and October 2022, 75 patients underwent EP for ampullary tumors and were diagnosed with AC based on the pathological features of the resected tissue. The factors associated with additional surgery after EP were also evaluated. RESULTS: A total of 67 patients had ACs ranging from carcinoma in situ to tumors limited to the mucosa (M group), and eight patients had ACs ranging from those limited to the sphincter of Oddi to those invading the duodenal muscularis propria (OD group). The 3-year endoscopic tumor control (condition not requiring additional surgery) rates in the M and OD groups were 90.8% and 84.6% (p = .033), respectively. In the M group, the presence of tumor components in the resection margins was the only significant factor associated with additional surgeries (p = .010) in the univariate analysis. The 3-year endoscopic tumor control rates were 100% for negative and uncertain resection margins and 76.6% for positive margins (p = .009). CONCLUSIONS: If the AC is confined to the mucosa and the resection margins are negative or uncertain, the tumor can be well-controlled endoscopically.

Meflin is a marker of pancreatic stellate cells involved in fibrosis and epithelial regeneration in the pancreas.

Pancreatic stellate cells (PSCs) are stromal cells in the pancreas that play an important role in pancreatic pathology. In chronic pancreatitis (CP) and pancreatic ductal adenocarcinoma (PDAC), PSCs are known to get activated to form myofibroblasts or cancer-associated fibroblasts (CAFs) that promote stromal fibroinflammatory reactions. However, previous studies on PSCs were mainly based on the findings obtained using ex vivo expanded PSCs, with few studies that addressed the significance of in situ tissue-resident PSCs using animal models. Their contributions to fibrotic reactions in CP and PDAC are also lesser-known. These limitations in our understanding of PSC biology have been attributed to the lack of specific molecular markers of PSCs. Herein, we established Meflin (Islr), a glycosylphosphatidylinositol-anchored membrane protein, as a PSC-specific marker in both mouse and human by using human pancreatic tissue samples and Meflin reporter mice. Meflin-positive (Meflin+ ) cells contain lipid droplets and express the conventional PSC marker Desmin in normal mouse pancreas, with some cells also positive for Gli1, the marker of pancreatic tissue-resident fibroblasts. Three-dimensional analysis of the cleared pancreas of Meflin reporter mice showed that Meflin+ PSCs have long and thin cytoplasmic protrusions, and are localised on the abluminal side of vessels in the normal pancreas. Lineage tracing experiments revealed that Meflin+ PSCs constitute one of the origins of fibroblasts and CAFs in CP and PDAC, respectively. In these diseases, Meflin+ PSC-derived fibroblasts showed a distinctive morphology and distribution from Meflin+ PSCs in the normal pancreas. Furthermore, we showed that the genetic depletion of Meflin+ PSCs accelerated fibrosis and attenuated epithelial regeneration and stromal R-spondin 3 expression, thereby implying that Meflin+ PSCs and their lineage cells may support tissue recovery and Wnt/R-spondin signalling after pancreatic injury and PDAC development. Together, these data indicate that Meflin may be a marker specific to tissue-resident PSCs and useful for studying their biology in both health and disease. © 2023 The Pathological Society of Great Britain and Ireland.

Monoclonal Antibody Against Mature Interleukin-18 Ameliorates Colitis in Mice and Improves Epithelial Barrier Function.

BACKGROUND: Antitumor necrosis factor (TNF)-α antibodies have improved the outcome of inflammatory bowel disease (IBD); but half of patients remain unresponsive to treatment. Interleukin-18 (IL-18) gene polymorphism is associated with resistance to anti-TNF-α antibodies, but therapies targeting IL-18 have not been clinically applied. Only the mature protein is biologically active, and we aimed to investigate whether specific inhibition of mature IL-18 using a monoclonal antibody (mAb) against a neoepitope of caspase-cleaved mature IL-18 could be an innovative treatment for IBD. METHODS: The expression of precursor and mature IL-18 in patients with UC was examined. Colitis was induced in C57/BL6 mice by administering dextran sulfate sodium (DSS), followed by injection with anti-IL-18 neoepitope mAb. Colon tissues were collected and subjected to histological analysis, immunohistochemistry, immunoblotting, and quantitative polymerase chain reaction. Colon epithelial permeability and microbiota composition were analyzed. RESULTS: Mature IL-18 expression was elevated in colon tissues of patients with active ulcerative colitis. Administration of anti-IL-18 neoepitope mAb ameliorated acute and chronic DSS-induced colitis; reduced interferon-γ, TNF-α, and chemokine (CXC motif) ligand-2 production and epithelial cell permeability; promoted goblet cell function; and altered the intestinal microbiome composition. The suppressive effect of anti-IL-18 neoepitope mAb was superior to that of anti-whole IL-18 mAb. Furthermore, combination therapy with anti-TNF-α Ab suppressed acute and chronic colitis additively by suppressing cytokine expressions and reducing cell permeability by upregulating claudin1 and occludin expression. CONCLUSIONS: Anti-IL-18 neoepitope mAb ameliorates acute and chronic colitis, suggesting that this mAb will be an innovative therapeutic option for IBD.

We investigate a novel monoclonal antibody that specifically recognizes a neoepitope of caspase-cleaved IL-18 and alleviates dextran sulfate sodium-induced colitis by suppressing the secretion of inflammatory cytokines, improving intestinal epithelial permeability, promoting goblet cell function, and regulating intestinal microbiota.

Current status of and future issues related to endoscopic papillectomy.

Endoscopic papillectomy is widely performed to treat duodenal papillary tumors, particularly at high-volume centers. It is indicated for adenomas without intraductal extension of the bile or pancreatic ducts. However, despite numerous reports of carcinomas that expand the indications to include well-differentiated adenocarcinomas that do not invade the sphincter of Oddi, the low agreement between biopsy and final pathological diagnosis, as well as the current inability of imaging modalities to diagnose sphincter of Oddi invasion, makes it difficult to consider expanding indications. Although complications can be prevented by certain methods, such as pancreatic duct stenting, and the frequency of severe complications has decreased, the safety of the procedure remains unconfirmed. In the future, this technology is expected to progress and enable wider applications, including those in tumors with extensive horizontal spread and those with intraductal extension of the bile and pancreatic ducts. Such technology may also improve the safety and accuracy of diagnosis.

Cutting edge of endoscopic ultrasound-guided fine-needle aspiration for solid pancreatic lesions.

This article provides an extensive review of the advancements and future perspectives related to endoscopic ultrasound-guided tissue acquisition (EUS-TA) for the diagnosis of solid pancreatic lesions (SPLs). EUS-TA, including fine-needle aspiration (EUS-FNA) and fine-needle biopsy (EUS-FNB), has revolutionized the collection of specimens from intra-abdominal organs, including the pancreas. Improvements in the design of needles, collection methods, and specimen processing techniques have improved the diagnostic performance. This review highlights the latest findings regarding needle evolution, actuation number, sampling methods, specimen evaluation techniques, application of artificial intelligence (AI) for diagnostic purposes, and use of comprehensive genomic profiling (CGP). It acknowledges the rising use of Franseen and fork-tip needles for EUS-FNB and emphasizes that the optimal number of actuations requires further study. Methods such as the door-knocking and fanning techniques have shown promise for increasing diagnostic performance. Macroscopic on-site evaluation (MOSE) is presented as a practical rapid specimen evaluation method, and the integration of AI is identified as a potentially impactful development. The study also underscores the importance of optimal sampling for CGP, which can enhance the precision of cancer treatment. Ongoing research and technological innovations will further improve the accuracy and efficacy of EUS-TA.

Real-World Effectiveness and Risk Factors for Discontinuation of Ustekinumab in Ulcerative Colitis.

Introduction: Ustekinumab (UST) has been approved for the treatment of moderate-to-severe ulcerative colitis (UC). Real-world data showing the effectiveness and safety of UST are necessary to confirm the results of clinical trials for applicability in daily clinical practice. Although some studies have reported real-world evidence of UST, only few studies have confirmed its effectiveness in the real world. The aim of this study was to assess the short- and long-term effectiveness, durability, safety, and risk factors for discontinuation of UST in UC in clinical practice. Methods: This was a retrospective, single-center, observational study. From March 2020 to January 2023, all consecutive patients with active UC who were treated with UST at Nagoya University Hospital were included. The primary outcome was the clinical remission rate at weeks 2-8 and weeks 24-48. The secondary outcomes included clinical response, persistence of UST therapy, endoscopic changes during follow-up, risk factors for UST discontinuation, and occurrence of any adverse events. The clinical effectiveness was evaluated using the Lichtiger score. Results: A total of 31 patients were included in this study. The clinical remission rates were 9.7%, 29.0%, 54.8%, and 64.5% at weeks 2, 8, 24, and 48, respectively. Twelve (38.7%) patients discontinued UST during the follow-up period. The probability of continuing UST was 93.5%, 80.6%, 77%, and 70% at weeks 2, 8, 24, and 48, respectively. The major reason for discontinuation of UST was primary failure (75.0%). A high baseline C-reactive protein (CRP) level was a significant risk factor for the discontinuation of UST. No adverse events were observed in this study. Conclusion: UST is effective for patients with UC. High CRP levels were identified as a risk factor for UST discontinuation. The findings of this study would help clinicians to select appropriate treatment options for patients with UC by identifying the risk factors for treatment discontinuation.

Clinical characteristics of Dieulafoy's lesion in the small bowel diagnosed and treated by double-balloon endoscopy.

BACKGROUND: Obscure gastrointestinal bleeding refers to bleeding for which the source cannot be ascertained even through balloon-assisted endoscopy. In certain instances, Dieulafoy's lesion in the small bowel is presumed to be the underlying cause. AIM: This retrospective study aimed to elucidate the clinical characteristics of Dieulafoy's lesion in the small bowel as diagnosed via double-balloon endoscopy while also exploring the feasibility of predicting bleeding from Dieulafoy's lesion prior to endoscopy in cases of obscure gastrointestinal bleeding. METHODS: A comprehensive analysis of our database was conducted, identifying 38 patients who received a diagnosis of Dieulafoy's lesion and subsequently underwent treatment via double-balloon endoscopy. The clinical background, diagnosis, and treatment details of patients with Dieulafoy's lesion were carefully examined. RESULTS: The median age of the 38 patients was 72 years, and 50% of the patients were male. A total of 26 (68%) patients exhibited a high comorbidity index. The upper jejunum and lower ileum were the most frequently reported locations for the occurrence of Dieulafoy's lesion in the small bowel. The detected Dieulafoy's lesions exhibited active bleeding (n = 33) and an exposed vessel with plaque on the surface (n = 5). Rebleeding after endoscopic treatment occurred in 8 patients (21%, median period: 7 days, range: 1-366 days). We conducted an analysis to determine the definitive nature of the initial double-balloon endoscopy diagnosis. Multivariate analysis revealed that hematochezia of ≥ 2 episodes constituted the independent factor associated with ≥ 2 double-balloon endoscopy diagnoses. Additionally, we explored factors associated with rebleeding following endoscopic treatment. Although the number of hemoclips utilized displayed a likely association, multivariate analysis did not identify any independent factor associated with rebleeding. CONCLUSION: If a patient encounters multiple instances of hematochezia, promptly scheduling balloon-assisted endoscopy, equipped with optional instruments without delay is advised, after standard endoscopic evaluation with esophagogastroduodenoscopy and colonoscopy is unrevealing.

Artificial intelligence in a prediction model for postendoscopic retrograde cholangiopancreatography pancreatitis.

OBJECTIVES: In this study we aimed to develop an artificial intelligence-based model for predicting postendoscopic retrograde cholangiopancreatography (ERCP) pancreatitis (PEP). METHODS: We retrospectively reviewed ERCP patients at Nagoya University Hospital (NUH) and Toyota Memorial Hospital (TMH). We constructed two prediction models, a random forest (RF), one of the machine-learning algorithms, and a logistic regression (LR) model. First, we selected features of each model from 40 possible features. Then the models were trained and validated using three fold cross-validation in the NUH cohort and tested in the TMH cohort. The area under the receiver operating characteristic curve (AUROC) was used to assess model performance. Finally, using the output parameters of the RF model, we classified the patients into low-, medium-, and high-risk groups. RESULTS: A total of 615 patients at NUH and 544 patients at TMH were enrolled. Ten features were selected for the RF model, including albumin, creatinine, biliary tract cancer, pancreatic cancer, bile duct stone, total procedure time, pancreatic duct injection, pancreatic guidewire-assisted technique without a pancreatic stent, intraductal ultrasonography, and bile duct biopsy. In the three fold cross-validation, the RF model showed better predictive ability than the LR model (AUROC 0.821 vs. 0.660). In the test, the RF model also showed better performance (AUROC 0.770 vs. 0.663, P = 0.002). Based on the RF model, we classified the patients according to the incidence of PEP (2.9%, 10.0%, and 23.9%). CONCLUSION: We developed an RF model. Machine-learning algorithms could be powerful tools to develop accurate prediction models.

Randomized trial comparing 15 vs 5 actuations per pass during endoscopic ultrasound-guided fine-needle biopsy for specimen acquisition of solid pancreatic lesions.

BACKGROUND AND AIM: There is currently no established number of actuations (to-and-fro movements) per pass during endoscopic ultrasound-guided fine-needle biopsy (EUS-FNB). This study aimed to compare 15 vs 5 actuations in terms of adequate specimen acquisition of solid pancreatic lesions. METHODS: In this prospective, randomized, crossover, noninferiority, single-center study, eligible patients underwent EUS-FNB using a 22-G Franseen needle with both 15 and 5 actuations per pass, performed in a randomized order, from October 2020 to December 2021. The acquired specimens from each pass were separately evaluated. The primary outcome was the accuracy of the histological diagnosis per pass. The noninferiority margin was set as 15%. RESULTS: Data from 85 patients were analyzed, revealing pancreatic cancer in 73 patients. The accuracy of the histological diagnosis in the 15 and 5 actuations groups was 83.5% (71/85) and 77.7% (66/85), respectively. The difference was -5.8% (95% confidence interval -15.6-3.4), which does not indicate noninferiority of the five actuations group. Among the secondary outcomes, the 15 actuations group was significantly superior to the five actuations group in terms of the obtained core tissues (1.88 [interquartile range 0.89-3.64] mm2 vs 1.66 [0.83-2.71] mm2 [P = 0.031]) and subjective evaluation of cytology specimens for pancreatic cancer (69.0% vs. 31.0%, P = 0.005). CONCLUSIONS: The noninferiority of five actuations in the accuracy of the histological diagnosis was not confirmed, and 15 actuations are preferred during EUS-FNB for solid pancreatic lesions.

CO2 enterography in endoscopic retrograde cholangiography using double-balloon endoscopy: A randomized clinical trial.

BACKGROUND AND AIM: Double-balloon endoscopic retrograde cholangiography (DBERC) is a valuable procedure for patients with altered gastrointestinal anatomy. Nonetheless, it is time-consuming and burdensome for both patients and endoscopists, partly because route selection in the reconstructed bowel with complicating loop is challenging. Carbon dioxide insufflation enterography is reportedly useful for route selection in the blind loop. This prospective randomized clinical trial investigated the usefulness of carbon dioxide insufflation enterography for route selection by comparing it with conventional observation. METHODS: Patients scheduled to undergo DBERC were consecutively registered. They were divided into carbon dioxide insufflation enterography and conventional groups via randomization according to stratification factors, type of reconstruction methods, and experience with DBERC. The primary endpoint was the correct rate of initial route selection. The secondary endpoints were the insertion time, examination time, amount of anesthesia drugs, and complications. RESULTS: The correct rate of route selection was significantly higher in the carbon dioxide insufflation enterography group (23/25, 92%) than in the visual method (15/25, 60%) (P = 0.018). The insertion time was significantly shorter in the carbon dioxide insufflation enterography group than in the visual group (10.8 ± 11.1 min vs 29.8 ± 15.7 min; P < 0.001). No significant differences in complications were noted between the two groups. The amounts of sedatives and analgesics used were significantly lower in the carbon dioxide insufflation enterography group (P < 0.001 and P < 0.001, respectively). CONCLUSIONS: Carbon dioxide insufflation enterography can reduce the burden of DBERC on patients and endoscopists by shortening the examination time and reducing the amount of medication.

Accuracy of Serum Leucine-Rich Alpha-2 Glycoprotein in Evaluating Endoscopic Disease Activity in Crohn's Disease.

BACKGROUND: Mucosal healing, confirmed by endoscopic evaluation, is the long-term goal of treatment for Crohn's disease (CD). Leucine-rich alpha-2 glycoprotein (LRG) is a new serum biomarker correlated with disease activity in inflammatory bowel disease. However, studies evaluating its relationship with CD, particularly in the context of small intestinal lesions, are scarce. The aim of this study was to investigate the accuracy of LRG in assessing endoscopic activity, especially remission, in patients with CD. METHODS: Between July 2020 and March 2021, 72 patients with CD who underwent LRG testing and double-balloon endoscopy at the same time were included. Endoscopic activity was evaluated using the applied Simple Endoscopic Score for Crohn's disease, including small intestine lesions. The relationship of LRG with clinical symptoms and endoscopic activity was assessed, and its predictive accuracy was evaluated. RESULTS: Leucine-rich alpha-2 glycoprotein showed a significant positive correlation with endoscopic activity (r = 0.619, P < .001), even in patients with active lesions in the small intestine (r = 0.626, P < .001). Multivariate logistic regression revealed that LRG was the only factor associated with endoscopic remission. An LRG cutoff value of 8.9 µg/mL had a sensitivity of 93.3%; specificity of 83.3%; positive predictive value of 96.6%; negative predictive value of 71.4%; accuracy of 91.7%; and area under the curve of 0.904 for the prediction of endoscopic remission. CONCLUSIONS: Leucine-rich alpha-2 glycoprotein can be used in assessing endoscopic activity and is a reliable marker of endoscopic remission in CD patients. It can be an intermediate target in the treatment of CD.

This study investigated leucine-rich alpha-2 glycoprotein's ability to assess endoscopic activity and endoscopic remission in patients with CD. The results showed that leucine-rich alpha-2 glycoprotein can assess endoscopic activity in CD patients and is a reliable marker of endoscopic remission.

Analysis of immunologic comorbidities in ulcerative colitis patients: a tool to prevent exacerbations in ulcerative colitis cases.

There have been previous studies, especially in Western countries and even in some areas in Asia, about extra-intestinal manifestations (EIMs) and its link with the outcome of inflammatory bowel disease (IBD), which includes Crohn's disease (CD), and ulcerative colitis (UC). This link is crucial when discussing a patient's prognosis and important when dealing with UC management. The aim of this study was to clarify the most common comorbidities associated with UC, emphasizing immunologic comorbidities in Japan. This study was a retrospective analysis performed at Nagoya University Hospital. The data collection started in March, 2019, and continued for two years. We retrieved the medical records of 105 patients with UC diagnosis, from which the data of 176 EIMs were extracted and analyzed. Results showed that EIMs with UC in the active phase accounted for 43.7% of total EIMs. Twenty-six patients with immune-mediated inflammatory disease frequently had an active phase (odds ratio [OR] 3.84, 99% CI, 1.44-10.27). Comorbidities showing an active manifestation of symptoms and UC in the active phase were significantly correlated in patients with immunological comorbidities, such as peripheral arthritis (r = 0.97, p < 0.01) and rheumatoid arthritis (RA) (r = 0.99, p < 0.01), as well as in patients with primary sclerosis cholangitis (PSC) (r = 0.98, p < 0.01). In conclusion, this analysis suggests the importance of having full comprehension of how immunological comorbidities affect the natural development of UC, which is of vital importance to prevent further UC complications and properly adjust the management of the disease.

[Leptomeningeal carcinomatosis from duodenal papillary carcinoma].

A woman in her 50s presented with ataxia and repeated falls during 2nd line S-1 therapy for duodenal papillary carcinoma with metastasis. She was diagnosed with leptomeningeal carcinomatosis based on gadolinium contrast-enhanced magnetic resonance imaging (MRI) and cerebrospinal fluid (CSF) examination, although plain computed tomography (CT) and MRI of the head showed no intracranial occupying lesions. This is a rare leptomeningeal carcinomatosis case with duodenal papillary carcinoma as the primary lesion, although aggressive treatment was not possible due to the decreased consciousness level.

The role of EUS elastography-guided fine needle biopsy in the histological diagnosis of solid pancreatic lesions: a prospective exploratory study.

This study aimed to evaluate the feasibility and efficacy of Endoscopic ultrasound elastography-guided fine needle biopsy (EUS-EG-FNB) for the diagnosis of pancreatic mass lesions. EUS-EG images were classified into heterogeneous and homogeneous groups. For the heterogeneous group, EUS-FNB was separately performed in both hard areas and soft areas. Only samples obtained during the first two passes (hard/soft areas) were used to compare the diagnostic accuracy as well as the quality and quantity of the specimens. We investigated the association of EUS-EG findings using strain histogram analysis with the histological findings. Fifty-five patients were enrolled including 25 patients with heterogeneous group. The homogeneous group had significantly lower mean strain value (hard) lesions. The adequate sampling rates from hard and soft areas were 88 and 92%, respectively (P = 0.6374). Comparison of the diagnostic accuracy and the quality and quantity of the histological core between hard and soft areas showed no significant differences. In pancreatic adenocarcinoma cases, the proportion of fibrous stroma in the core tissue was significantly correlated with the elasticity of the region. (R2 = 0.1226: P = 0.0022) EUS-EG may reflect tissue composition in pancreatic tumors, however, EUS-EG did not affect either the quality and quantity of the tissues obtained.Clinical Trial Registry No: UMIN-000033073.

Comparison of an Inside Stent and a Fully Covered Self-Expandable Metallic Stent as Preoperative Biliary Drainage for Patients with Resectable Perihilar Cholangiocarcinoma.

Background: There is a need for a more tolerable preoperative biliary drainage (PBD) method for perihilar cholangiocarcinoma (PHCC). In recent years, inside stents (ISs) have attracted attention as a less suffering PBD method. Few studies have compared IS with a fully covered self-expandable metallic stent (FCSEMS) as PBD for resectable PHCC. The aim of this study is to compare them. Methods: This study involved 86 consecutive patients (IS: 51; FCSEMS: 35). The recurrent biliary obstruction (RBO) rate until undergoing surgery or being diagnosed as unresectable, time to RBO, factors related to RBO, incidence of adverse events related to endoscopic retrograde cholangiography, and postoperative complications associated with each stent were evaluated retrospectively. Results: There was no significant difference between the two groups in the incidence of adverse events after stent insertion. After propensity score matching, the mean (SD) time to RBO was 37.9 (30.2) days in the IS group and 45.1 (35.1) days in the FCSEMS group, with no significant difference (P=0.912, log-rank test). A total of 7/51 patients in the IS group and 3/35 patients in the FCSEMS group developed RBO. The only risk factor for RBO was bile duct obstruction of the future excisional liver lobe(s) due to stenting (HR 29.8, P=0.008) in the FCSEMS group, but risk factors could not be indicated in the IS group. There was no significant difference in the incidence of bile leakage or liver failure. In contrast, pancreatic fistula was significantly more common in the FCSEMS group (13/23 patients) than in the IS group (3/28 patients) (P < 0.001), especially in patients who did not undergo pancreatectomy (P=0.001). Conclusions: As PBD, both IS and FCSEMS achieved low RBO rates. Compared with FCSEMS, IS shows no difference in RBO rate, is associated with fewer postoperative complications, and is considered an appropriate means of PBD for resectable PHCC. This trail is registered with UMIN000025631.