Risk factors of unintentional piecemeal resection in endoscopic mucosal resection for colorectal polyps ≥ 10 mm.

This study aimed to investigate the lesion and endoscopist factors associated with unintentional endoscopic piecemeal mucosal resection (uniEPMR) of colorectal lesions ≥ 10 mm. uniEPMR was defined from the medical record as anything other than a preoperatively planned EPMR. Factors leading to uniEPMR were identified by retrospective univariate and multivariate analyses of lesions ≥ 10 mm (adenoma including sessile serrated lesion and carcinoma) that were treated with endoscopic mucosal resection (EMR) at three hospitals. Additionally, a questionnaire survey was conducted to determine the number of cases treated by each endoscopist. A learning curve (LC) was created for each lesion size based on the number of experienced cases and the percentage of uniEPMR. Of 2557 lesions, 327 lesions underwent uniEPMR. The recurrence rate of uniEPMR was 2.8%. Multivariate analysis showed that lesion diameter ≥ 30 mm (odds ratio 11.83, 95% confidence interval 6.80-20.60, p < 0.0001) was the most associated risk factor leading to uniEPMR. In the LC analysis, the proportion of uniEPMR decreased for lesion sizes of 10-19 mm until 160 cases. The proportion of uniEPMR decreased with the number of experienced cases in the 20-29 mm range, while there was no correlation between the number of experienced cases and the proportion of uniEPMR ≥ 30 mm. These results suggest that 160 cases seem to be the minimum number of cases needed to be proficient in en bloc EMR. Additionally, while lesion sizes of 10-29 mm are considered suitable for EMR, lesion sizes ≥ 30 mm are not applicable for en bloc EMR from the perspective of both lesion and endoscopist factors.

Specific peptide conjugation to a therapeutic antibody leads to enhanced therapeutic potency and thermal stability by reduced Fc dynamics.

Antibody-drug conjugates are powerful tools for combatting a wide array of cancers. Drug conjugation to a therapeutic antibody often alters molecular characteristics, such as hydrophobicity and effector function, resulting in quality deterioration. To develop a drug conjugation methodology that maintains the molecular characteristics of the antibody, we engineered a specific peptide for conjugation to the Fc region. We used trastuzumab and the chelator (DOTA) as model antibody and payload, respectively. Interestingly, peptide/DOTA-conjugated trastuzumab exhibited enhanced antibody-dependent cellular cytotoxicity (ADCC) and increased thermal stability. Detailed structural and thermodynamic analysis clarified that the conjugated peptide blocks the Fc dynamics like a "wedge." We revealed that (1) decreased molecular entropy results in enhanced ADCC, and (2) blockade of Fc denaturation results in increased thermal stability. Thus, we believe that our methodology is superior not only for drug conjugation but also as for reinforcing therapeutic antibodies to enhance ADCC and thermal stability.

Target-independent Immune-cell Activation by Aggregates of T Cell-redirecting Bispecific Antibodies.

T cell-redirecting bispecific antibodies (bsAbs) have been under development as a new class of biotherapeutics for cancer immunotherapy. T cell-redirecting bsAbs simultaneously bind tumor-associated antigens on tumor cells and CD3 on T cells, resulting in T cell-mediated cytotoxicity against tumor cells. In this study, we prepared a tandem scFv-typed bsAb targeting HER2 and CD3 (HER2-CD3), and evaluated the impact of aggregation of HER2-CD3 on the in vitro immunotoxicity. A cell-based assay using CD3-expressing reporter cells revealed that the aggregates of HER2-CD3 directly activated CD3-expressing immune cells in the absence of target antigen (HER2)-expressing cells. Comparison of the aggregates generated under various stress conditions indicated the possibility that insoluble protein particles, which were detected by qLD analysis and contained non-denatured functional domains, contributed to the activation of CD3-expressing immune cells. In addition, HER2-CD3 aggregates stimulated hPBMCs and strongly induced the secretion of inflammatory cytokines and chemokines. The cytokine/chemokine-release profiles suggested that the aggregates could induce inflammatory responses not only by CD3-mediated T cell activation but also by other immune cell activations. These results indicated the potential risk of aggregation of T cell-redirecting bsAbs, which could induce unwanted immune cell activation and inflammation and thereby immune-mediated adverse reactions.

Characterization of anti-SARS-CoV-2 monoclonal antibodies focusing on antigen binding, neutralization, and FcγR activation via formation of immune complex.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes coronavirus disease 2019 (COVID-19). Antibodies induced by SARS-CoV-2 infection or vaccination play pivotal roles in the body's defense against the virus; many monoclonal antibodies (mAbs) against SARS-CoV-2 have been cloned, and some neutralizing mAbs have been used as therapeutic drugs. In this study, we prepared an antibody panel consisting of 31 clones of anti-SARS-CoV-2 mAbs and analyzed and compared their biological activities. The mAbs used in this study were classified into different binding classes based on their binding epitopes and showed binding to the SARS-CoV-2 spike protein in different binding kinetics. A multiplex assay using the spike proteins of Alpha, Beta, Gamma, Delta, and Omicron variants clearly showed the different effects of variant mutations on the binding and neutralization activities of different binding classes of mAbs. In addition, we evaluated Fcγ receptor (FcγR) activation by immune complexes consisting of anti-SARS-CoV-2 mAb and SARS-CoV-2 pseudo-typed virus, and revealed differences in the FcγR activation properties among the binding classes of anti-SARS-CoV-2 mAbs. It has been reported that FcγR-mediated immune-cell activation by immune complexes is involved in the promotion of immunopathology of COVID-19; therefore, differences in the FcγR-activation properties of anti-SARS-CoV-2 mAbs are among the most important characteristics when considering the clinical impacts of anti-SARS-CoV-2 mAbs.

FcγRIIIa-158V/F polymorphism affects the performance of FcγRIIIa-related bioassay.

Bioassays are important for estimating biosimilarity between biological products. Comparability studies including bioassays are needed to demonstrate that a biosimilar product has no meaningful differences that affect safety and efficacy compared with the reference product. Among the most important biological characteristics of therapeutic mAbs are Fc-mediated functions, which induce immune-cell activation which can affect both efficacy and safety. Thus, when developing biosimilar products of therapeutic mAbs, it is necessary to compare the Fc-mediated functions by using various bioassays. Though it is reported that polymorphism of Fcγ receptors (FcγRs) affects Fc-mediated cellular activations of therapeutic mAbs, the impacts of the polymorphism of FcγRs on bioassay performance are still unclear. In this study, we evaluated the impact of FcγRIIIa-158V/F polymorphism on assay performance in distinguishing differences in the biological activities of therapeutic mAbs. The results showed that different bioassay methods produced different assessments of biological activities of mAbs, and that the FcγRIIIa-158V/F polymorphism clearly affected the performance of the FcγRIIIa-binding assay using recombinant proteins and FcγRIIIa-expressing reporter assays. That is, the assays using the FcγRIIIa-158F variant were superior to those using the FcγRIIIa-158V variant in distinguishing the difference in FcγRIIIa-binding and -activation properties. These results indicate that we should evaluate the comparability of biosimilars by considering the impacts of FcγRIIIa-158V/F polymorphism on bioassay performance.

Fcγ Receptor-Dependent Internalization and Off-Target Cytotoxicity of Antibody-Drug Conjugate Aggregates.

PURPOSE: Antibody-drug conjugates (ADCs), which are monoclonal antibodies (mAbs) conjugated with highly toxic payloads, achieve high tumor killing efficacy due to the specific delivery of payloads in accordance with mAbs' function. On the other hand, the conjugation of payloads often increases the hydrophobicity of mAbs, resulting in reduced stability and increased aggregation. It is considered that mAb aggregates have potential risk for activating Fcγ receptors (FcγRs) on immune cells, and are internalized into cells via FcγRs. Based on the mechanism of action of ADCs, the internalization of ADCs into target-negative cells may cause the off-target toxicity. However, the impacts of aggregation on the safety of ADCs including off-target cytotoxicity have been unclear. In this study, we investigated the cytotoxicity of ADC aggregates in target-negative cells. METHODS: The ADC aggregates were generated by stirring stress or thermal stress. The off-target cytotoxicity of ADC aggregates was evaluated in several target-negative cell lines, and FcγR-activation properties of ADC aggregates were characterized using a reporter cell assay. RESULTS: Aggregation of ADCs enhanced the off-target cytotoxicity in several target-negative cell lines compared with non-stressed ADCs. Notably, ADC aggregates with FcγR-activation properties showed dramatically enhanced cytotoxicity in FcγR-expressing cells. The FcγR-mediated off-target cytotoxicity of ADC aggregates was reduced by using a FcγR-blocking antibody or Fc-engineering for silencing Fc-mediated effector functions. CONCLUSIONS: These results indicated that FcγRs play an important role for internalization of ADC aggregates into non-target cells, and the aggregation of ADCs increases the potential risk for off-target toxicity.

Recovery of bowel function after transperitoneal or retroperitoneal laparoscopic pyeloplasty. A multi-center study.

AIM: To document the recovery of bowel function (BF) in children after transperitoneal (TP) or retroperitoneal (RP) laparoscopic pyeloplasty. METHODS: Data were obtained retrospectively from four centers between 2008 and 2019 for TP (n = 51) and RP (n = 58). Each surgeon chose which technique to perform. RESULTS: Subject demographics were not significantly different. Differences in operative times were not significant (RP: 241 min versus TP: 225 min). Mean duration/requirement for postoperative epidural/intravenous analgesia were not significantly different (TP: 1.4 days versus RP: 1.3 days) and (TP: 66.7% versus RP: 67.2%), respectively. Postoperative nasogastric (NG) intubation was more common in RP (TP: 19.6% versus RP: 44.8%; p < .05). NG aspiration (TP: 0.15 mL/kg/hr versus RP: 0.16 mL/kg/hr), nausea (TP: 31.4% versus RP: 17.2%), and vomiting (TP: 19.6% versus RP: 15.5%) were not significantly different. There were no perioperative complications (including ileus). Abdominal distention was problematic in one case per group (TP: 2.0% versus RP: 1.7%). Times for oral liquid (TP: 0.69 day versus RP: 0.83 day), solid food (TP: 0.88 day versus RP 1.07 days), and the first bowel movement (TP: 2.86 days versus RP: 2.79 days), were not significantly different. CONCLUSIONS: BF recovery would appear to be consistent, independent of technique.

The influence of antibody engineering on Fc conformation and Fc receptor binding properties: Analysis of FcRn-binding engineered antibodies and an Fc fusion protein.

Therapeutic immunoglobulin G (IgG) antibodies have comparatively long half-lives because the neonatal Fc receptor (FcRn) binds to the IgG Fc at acidic pH in the endosome and protects IgG from degradation. To further prolong the half-lives, amino acid-substituted antibodies having high affinity to FcRn are being developed, and one such therapeutic antibody (ravulizumab) has been approved. In this study, we investigated the binding property to FcγR and the conformation of seven FcRn affinity-modulated adalimumab variants to clarify the impact of the amino acid substitutions on the function and conformation of IgG Fc. The amino acid substitutions in T254-P261 caused a change in deuterium uptake into some regions of Fc in HDX-MS analysis, but those at T311, M432 and N438 did not cause such a change. The conformations around F245-L255 (FLFPPKPKDTL) were particularly influenced by the amino acid substitution in M256-P261, and the conformational changes of this region were correlated with the decrease of the affinity to FcγRIIIa. Additionally, we investigated the conformational difference of Fc between a Fc fusion protein (etanercept) and a native IgG (adalimumab). Although the Fc fusion proteins were expected to have similar FcRn affinity to IgGs, the affinity of etanercept to FcRn was lower than that of adalimumab, and its half-life was shorter than those of the IgG antibodies. Differences in deuterium uptakes were observed in the two regions where they were also detected in the adalimumab variants, and the conformational differences appeared to be an important factor for the low FcRn affinity of etanercept.

ABO Blood Group and Risk of Pancreatic Carcinogenesis in Intraductal Papillary Mucinous Neoplasms.

BACKGROUND: ABO blood group has been associated with risks of various malignancies, including pancreatic cancer. No study has evaluated the association of ABO blood group with incidence of pancreatic carcinogenesis during follow-up of patients with intraductal papillary mucinous neoplasms (IPMN). METHODS: Among 3,164 patients diagnosed with pancreatic cysts at the University of Tokyo (Tokyo, Japan) from 1994 through 2019, we identified 1,815 patients with IPMN with available data on ABO blood group. We studied the association of ABO blood group with incidence of pancreatic carcinoma, overall and by carcinoma types [IPMN-derived carcinoma or concomitant pancreatic ductal adenocarcinoma (PDAC)]. Utilizing competing-risks proportional hazards models, we estimated subdistribution hazard ratios (SHR) for incidence of pancreatic carcinoma with adjustment for potential confounders, including cyst characteristics. RESULTS: During 11,518 person-years of follow-up, we identified 97 patients diagnosed with pancreatic carcinoma (53 with IPMN-derived carcinoma and 44 with concomitant PDAC). Compared with patients with blood group O, patients with blood groups A, B, and AB had multivariable SHRs (95% confidence intervals) for pancreatic carcinoma of 2.25 (1.25-4.07; P = 0.007), 2.09 (1.08-4.05; P = 0.028), and 1.17 (0.43-3.19; P = 0.76), respectively. We observed no differential association of ABO blood group with pancreatic carcinoma incidence by carcinoma types. CONCLUSIONS: In this large long-term study, patients with IPMN with blood group A or B appeared to be at higher risk of pancreatic carcinoma compared with those with blood group O. IMPACT: ABO blood group can be a biomarker for pancreatic cancer risk among patients with IPMNs.

Endoscopic management of pancreatic diseases in patients with surgically altered anatomy: clinical outcomes of combination of double-balloon endoscopy- and endoscopic ultrasound-guided interventions.

OBJECTIVES: In patients with surgically altered anatomy, endoscopic treatment of pancreatic diseases is technically challenging. We aimed to evaluate the feasibility, effectiveness, and safety of an interchangeable combination of double-balloon endoscope-assisted ERP (DB-ERP) and endoscopic ultrasonography-guided pancreatic duct drainage (EUS-PD) in this clinical setting. METHODS: Consecutive patients with surgically altered anatomy undergoing endoscopic treatment (DB-ERP, EUS-PD, or both) for pancreatic diseases were studied. The primary outcome was technical success; secondary outcomes were clinical success and adverse events. RESULTS: Forty patients who underwent DB-ERP (38) and EUS-PD (2) as an initial intervention were retrospectively studied. Indications for intervention included 18 pancreaticojejunostomy anastomotic stricture (PJAS), four pancreatic duct stone (PDS), four pancreatic fistula (PF), 11 PJAS with PDS, and three PJAS with PF. Prior surgical reconstruction was 26 Billroth-II, 13 Roux-en-Y, and one Imanaga reconstruction. Along with salvage procedures including three DB-ERP and seven EUS-PD, the overall technical success rates of DB-ERP and EUS-PD were 70.7% (29/41) and 100% (9/9), respectively. Clinical success was achieved in 85.0% (34/40) by combination of DB-ERP and EUS-PD; successful drainage for PJAS, complete removal of PDS, and resolution of PF were achieved in 90.6%, 80.0%, and 71.4%, respectively. Adverse event rates were 12.2% (5/41; one perforation, and four pancreatitis) in DB-ERP and 55.6% (5/9; three pancreatic leakage, and two abdominal pain) in EUS-PD. CONCLUSIONS: A combination of DB-ERP and EUS-PD can achieve high technical and clinical success for pancreatic diseases in surgically altered anatomy patients. A prospective multicenter study to investigate an appropriate treatment algorithm is warranted.

Characterization of Aggregated Antibody-Silicone Oil Complexes: From Perspectives of Morphology, 3D Image, and Fcγ Receptor Activation.

Pre-filled syringes (PFS) have been in widespread use as an administration device for therapeutic antibodies in recent decades. Generally, the inner barrel and syringe of PFS are coated with silicone oil (SO) for lubrication. Multiple studies have focused on the fact that the SO adsorbs denatured antibody molecules, and induces antibody aggregation. Aggregated antibodies are recognized as a potential risk for evoking immunogenic responses in patients. The characteristics of the aggregated antibody-SO complexes, including their concentration, population, shape, three-dimensional (3D) image, and Fcγ Receptors (FcγRs) activation have been obscurely acknowledged so far. In the present work, we prepared aggregated antibody-SO complexes by agitation and analyzed using multifaceted techniques such as flow imaging, confocal fluorescence microscopy, and cell-based assays for FcγRs activation. The results emphasized that the SO accelerates the increase in sub-visible particles and antibody aggregation. The confocal fluorescence microscopy analysis revealed the high-resolution 3D images of aggregated antibody-SO complexes. The FcγRs reporter cell assay clarified that the pre-mixed and agitated Ab + SO have higher FcγRs activation capability compared to the agitated Ab. Overall, this study advances the view that SO has an effect to increase the risk of agitation-induced aggregated antibody particles.

Structural insight and stability of TNFR-Fc fusion protein (Etanercept) produced by using transgenic silkworms.

Therapeutic proteins expressed using transgenic animals have been of great interest for several years. Especially, transgenic silkworm has been studied intensively because of its ease in handling, low-cost, high-yield and unique glycosylation patterns. However, the physicochemical property of the therapeutic protein expressed in transgenic silkworm remains elusive. Here, we constructed an expression system for the TNFR-Fc fusion protein (Etanercept) using transgenic silkworm. The TNFR-Fc fusion protein was employed to N-glycan analysis, which revealed an increased amount of afucosylated protein. Evidence from surface plasmon resonance analysis showed that the TNFR-Fc fusion protein exhibit increased binding affinity for Fcγ receptor IIIa and FcRn compared to the commercial Etanercept, emphasizing the profit of expression system using transgenic silkworm. We have further discussed the comparison of higher order structure, thermal stability and aggregation of the TNFR-Fc fusion protein.

Feasibility of balloon endoscope-assisted endoscopic retrograde cholangiopancreatography for the elderly.

Background and study aims Endoscopic retrograde cholangiopancreatography (ERCP) for patients with surgically altered anatomy is challenging. Recently, balloon endoscopy has been shown to facilitate ERCP for this population with a high technical success rate, but adverse events (AEs) are not uncommon. Compared to non-elderly patients, elderly patients may be at higher risk of AEs due to underlying comorbidities. The current study aimed to evaluate the feasibility of balloon endoscope-assisted ERCP (BE-ERCP) for the elderly. Patients and methods We retrospectively identified patients who underwent BE-ERCP between January 2010 and September 2019. For patients who underwent multiple procedures during the study period, the first session was analyzed. Early AEs associated with BE-ERCP were compared between elderly (≥ 75 years) and non-elderly patients. Results A total of 1,363 BE-ERCP procedures were performed, and 568 patients (211 elderly and 357 non-elderly) were included for the analyses. Technical success rates were high in both the elderly and non-elderly groups (80 % vs. 80 %, respectively). The rates of early AEs were similar between the groups (12 % vs. 9.0 % in the elderly and non-elderly group, respectively; P  = 0.31). The mltivariable-adjusted odds ratio for early AEs comparing elderly to non-elderly patients was 1.36 (95 % confidence interval, 0.74-2.51; P  = 0.32). Specifically, we did not observe between-group differences in rates of gastrointestinal perforation (2.4 % vs. 2.8 % in elderly and non-elderly groups, respectively; P  = 0.99) and aspiration pneumonia (1.9 % vs. 0.6 %, P  = 0.20). Conclusions BE-ERCP is a feasible procedure for elderly individuals with surgically altered anatomy.

Endoscopic Ultrasound-Guided Tissue Acquisition by 22-Gauge Franseen and Standard Needles for Solid Pancreatic Lesions.

Background/Aims: Recently, a three-plane symmetric needle with Franseen geometry was developed for endoscopic ultrasound-guided fine needle biopsy (EUS-FNB). In this retrospective study, tissue acquisition per pass was compared between 22-gauge Franseen FNB and standard fine needle aspiration (FNA) needles in patients with solid pancreatic lesions. Methods: Consecutive patients who underwent EUSFNA or EUS-FNB for solid pancreatic lesions between October 2014 and March 2018 were retrospectively studied. The tissue acquisition rate and the diagnostic performance per session, per pass, and at first pass were compared. Results: A total of 663 passes (300 by the FNB needle and 363 by the standard FNA needle) were performed in 154 patients (71 FNB and 83 FNA). The tissue acquisition rate per session and at first pass in the FNB and FNA groups was 100% and 95% (p=0.13) and 87% and 69% (p=0.007), respectively. The multivariate analysis revealed that among the patients, EUS-FNB (odds ratio, 3.07; p=0.01) was associated with a higher first-pass tissue acquisition rate. While the tissue acquisition rate reached a plateau after the 4th pass with FNA, it reached a plateau after the 2nd pass with FNB. Among the 129 malignant cases, the histological tissue acquisition rate per session was similar (100% and 94%), but the sensitivity by histology alone per session was higher for FNB than for FNA (93% and 73%, p<0.01). Conclusions: The results of our retrospective analysis indicated that compared with a standard FNA needle, a 22-gauge Franseen FNB needle was associated with a higher first-pass tissue acquisition rate.

The impact of age and comorbidity in advanced or recurrent biliary tract cancer receiving palliative chemotherapy.

BACKGROUND AND AIM: Limited data are available on age and comorbidity assessment in patients with biliary tract cancer (BTC). This study aimed to evaluate the association of age and comorbidity burden with clinical outcomes of chemotherapy for BTC. METHODS: Consecutive 197 BTC patients undergoing first-line chemotherapy between 2007 and 2017 were retrospectively studied. Patients were classified to three groups according to the age-adjusted Charlson comorbidity index (ACCI) excluding the score about BTC and progression-free survival, overall survival (OS), and safety were compared. RESULTS: Fifty-one patients (26%) were elderly (≥ 75 years), and ACCI was 0-2 in 73 patients (37%), 3-4 in 98 (50%), and ≥ 5 in 26 (13%). ACCI was associated with the administration of first-line combination chemotherapy (89% in 0-2, 80% in 3-4, and 64% in ≥ 5, P < 0.01) and second-line chemotherapy (67% in 0-2, 51% in 3-4, and 35% in ≥ 5, P = 0.01). ACCI was prognostic for OS in addition to performance status, disease status, and CA19-9: The hazard ratios in ACCI of 3-4 and ≥ 5 were 1.39 and 1.79, compared with ACCI of 0-2 (P = 0.04). While overall safety profile did not differ by ACCI, higher ACCI score group developed Grade 3-4 neutropenia more frequently (26% in 0-2, 42% in 3-4, and 46% in ≥ 5, P = 0.04). CONCLUSION: Age and comorbidity burden did affect OS and safety profile in BTC patients undergoing first-line palliative chemotherapy. ACCI can be a simple and useful tool to evaluate the age and comorbidity burden in these patients.

Lenvatinib-induced acute acalculous cholecystitis in a patient with hepatocellular carcinoma.

The patient was a 67-year-old man with advanced hepatocellular carcinoma (HCC) due to chronic hepatitis B. Due to refractoriness to radiofrequency ablation and transcatheter arterial chemoembolization, lenvatinib, a new oral mutikinase inhibitor, was started with a daily dose of 12 mg. However, on day 6 the patient developed acute-onset, right upper quadrant pain associated with fever; laboratory tests revealed leukocytosis and liver dysfunction. CT scan showed the swollen gallbladder with wall thickening with no evidence of gallstones, and the diagnosis of acute acalculous cholecystitis was made. After the resolution of cholecystitis by antibiotics and endoscopic nasogallbladder drainage placement, lenvatinib was resumed at a reduced daily dose of 4 mg. However, acute acalculous cholecystitis recurred, supporting lenvatinib as a cause of acute acalculous cholecystitis. Using the Naranjo adverse drug reaction probability scale, a score of 6 was derived, which indicates that this adverse event was probably caused by lenvatinib. In summary, we present a patient with advanced HCC who underwent repeated episodes of acute acalculous cholecystitis as a rare adverse event associated with lenvatinib.

Retrospective Comparative Study of Side-by-Side and Stent-in-Stent Metal Stent Placement for Hilar Malignant Biliary Obstruction.

BACKGROUND: In patients with unresectable hilar malignant biliary obstruction (MBO), bilateral metal stent placement is recommended. However, treatment selection between partially stent-in-stent (SIS) and side-by-side (SBS) methods is still controversial. STUDY: Clinical outcomes of bilateral metal stent placement by SBS and SIS methods for hilar MBO were retrospectively studied in four Japanese centers. While large-cell-type uncovered metal stents were placed above the papilla in SIS, braided-type uncovered metal stents were placed across the papilla in SBS. RESULTS: A total of 64 patients with hilar MBO (40 SIS and 24 SBS) were included in the analysis. Technical success rate was 100% in SIS and 96% in SBS. Functional success rate was 93% in SIS and 96% in SBS. Early adverse event rates were higher in SBS (46%) than in SIS (23%), though not statistically significant (P = 0.09). Post-procedure pancreatitis was exclusively observed in SBS group (29%). Recurrent biliary obstruction rates were 48% and 43%, and the median time to recurrent biliary obstruction was 169 and 205 days in SIS and SBS, respectively. CONCLUSIONS: Other than a trend to higher adverse event rates including post-procedure pancreatitis in SBS, clinical outcomes of SIS and SBS methods were comparable in patients with unresectable hilar MBO.

A prospective study of fully covered metal stents for different types of refractory benign biliary strictures.

BACKGROUND: While endoscopic management of benign biliary strictures (BBSs) is the standard of care, long-term treatment remains the issue in refractory cases, especially for anastomotic strictures after living-donor liver transplantation (LDLT) and hepaticojejunostomy anastomotic strictures (HJAS). The aim of this prospective study was to evaluate the safety and effectiveness of a fully covered self-expandable metal stent (FCSEMS) for patients with refractory BBSs. METHODS: Patients with BBSs that were unamenable to endoscopic plastic stent placement with a treatment period of more than 6 months were eligible. An FCSEMS was placed endoscopically and removed after 90 days. In patients with surgically altered anatomy, an FCSEMS was placed using a double-balloon endoscope. The primary outcome was stricture resolution at FCSEMS removal. The secondary outcomes included stricture recurrence and adverse events. RESULTS: A total of 30 patients were enrolled: the causes of their BBSs were anastomotic stricture after LDLT in 13, HJAS in 12, post-cholecystectomy in two, chronic pancreatitis in two, and post-hepatectomy in one. The technical success rate of FCSEMS placement was 100 % and all FCSEMSs were successfully removed. The rate of stricture resolution at FCSEMS removal was 96.6 % (91.7 % in the post-LDLT group and 100 % in the HJAS group). Stricture recurrence occurred in three HJAS patients (10.7 %) during a median follow-up period of 15.6 months. Adverse events were observed in 12.1 %: five cholangitis, one pancreatitis, and one perforation. CONCLUSION: Temporary placement of an FCSEMS was a feasible and effective treatment option for refractory BBSs, especially for post-LDLT strictures and HJAS.

Prediction of the Probability of Malignancy in Mucinous Cystic Neoplasm of the Pancreas With Ovarian-Type Stroma: A Nationwide Multicenter Study in Japan.

OBJECTIVE: The aim of the study was to develop a formula for predicting the probability of malignancy of mucinous cystic neoplasm (MCN) of the pancreas with ovarian-type stroma. METHODS: A total of 364 patients were enrolled. A total score was calculated as the sum of the approximate integers of the odds ratios of the predictive factors identified by multivariate analysis. The relationship between the total score and pathological results was assessed. RESULTS: A total of 321 patients had benign MCN and 43 had malignant MCN. Five possible predictive factors were analyzed: 56 years or older, high serum carcinoembryonic antigen level, high carbohydrate antigen 19-9 level, tumor size of 51 mm or greater, and the presence of mural nodules. The total score was significantly higher in patients with malignant MCN (median, 24; range, 0-37) compared with benign MCN (median, 5; range, 0-33; P < 0.001). Receiver operating characteristic curve analysis demonstrated that the area under the curve was 0.86, and the sensitivity and specificity of the total score for discriminating malignant MCNs were 72% and 83%, respectively, using a cut-off value of 22. CONCLUSIONS: The current simple formula can predict the malignancy of MCN and may thus contribute to the adequate management of patients with MCN.

Regular Statin Use and Incidence of Postendoscopic Retrograde Cholangiopancreatography Pancreatitis.

GOALS AND BACKGROUND: Endoscopic retrograde cholangiopancreatography is widely utilized to diagnose and treat various pancreaticobiliary diseases, but postendoscopic retrograde cholangiopancreatography pancreatitis (PEP) can be a fatal adverse event. Evidence suggests that statins may exhibit suppressive effects on inflammation in the pancreas. We carried out an observational cohort study to examine the protective effect of statins on PEP. STUDY: We retrospectively identified consecutive patients who underwent endoscopic retrograde cholangiopancreatography at a tertiary care center in Japan between January 2010 and January 2019. The incidences of PEP were compared between regular and nonregular statin users. Using the multivariable logistic regression model, we examined the association of regular statin use with the incidence of PEP controlling for potential risk factors for PEP. RESULTS: We included 2664 patients (328 regular statin users and 2336 nonregular users). The incidence of PEP did not differ by statin use status (P=0.52): 8.8% in regular statin users and 7.9% in nonregular users. The multivariable-adjusted odds ratio for PEP comparing regular statin use with nonregular use was 1.08 (95% confidence interval, 0.67-1.72; P=0.76). When we examined specific statin types (hydrophilic and lipophilic statins), we consistently observed the null association: 6.8% of 132 hydrophilic statin users and 10% of 196 lipophilic statin users (P=0.74 and 0.27, respectively, compared with nonregular users). CONCLUSIONS: Regular statin use was not shown to be protective against PEP. A further investigation is warranted before this medication is tested in prospective randomized trials.