K-ras mutation detected by peptide nucleic acid-clamping polymerase chain reaction, Ki-67, S100P, and SMAD4 expression can improve the diagnostic accuracy of inconclusive pancreatic EUS-FNB specimens.

OBJECTIVES: We aimed to assess the diagnostic utility of an immunohistochemical panel including calcium-binding protein P, p53, Ki-67, and SMAD family member 4 and K-ras mutation for diagnosing pancreatic solid lesion specimens obtained by endoscopic ultrasound-guided fine-needle biopsy and to confirm their usefulness in histologically inconclusive cases. METHODS: Immunohistochemistry and peptide nucleic acid-clamping polymerase chain reaction for K-ras mutation were performed on 96 endoscopic ultrasound-guided fine-needle biopsy specimens. The diagnostic efficacy of each marker and the combination of markers was calculated. The diagnostic performances of these markers were evaluated in 27 endoscopic ultrasound-guided fine-needle biopsy specimens with histologically inconclusive diagnoses. A classification tree was constructed. RESULTS: K-ras mutation showed the highest accuracy and consistency. Positivity in more than two or three of the five markers showed high diagnostic accuracy (94.6 % and 93.6 %, respectively), and positivity for more than three markers showed the highest accuracy for inconclusive cases (92.0 %). A classification tree using K-ras mutation, Ki-67, S100P, and SMAD4 showed high diagnostic performance, with only two misclassifications in inconclusive cases. CONCLUSIONS: K-ras mutation detection via peptide nucleic acid-clamping polymerase chain reaction is a stable and accurate method for distinguishing between pancreatic ductal adenocarcinoma and non-pancreatic ductal adenocarcinoma lesions. A classification tree using K-ras mutation, Ki-67, S100P, and SMAD4 helps increase the diagnostic accuracy of cases that are histologically difficult to diagnose.

Comparison of long-term outcomes of endoscopic ultrasound-guided hepaticogastrostomy and choledochoduodenostomy for distal malignant biliary obstruction: a multicenter retrospective study.

Background: Endoscopic ultrasound-guided biliary drainage (EUS-BD), classified as choledochoduodenostomy (CDS) and hepaticogastrostomy (HGS), is a feasible and effective alternative for distal malignant biliary obstruction (MBO) in failed endoscopic retrograde cholangiopancreatography. However, the preferred technique for better outcomes has not yet been evaluated. Objectives: We compared the long-term outcomes between the techniques. Design: Retrospective comparative study. Methods: We reviewed consecutive patients who underwent EUS-CDS or EUS-HGS with transmural stent placement for distal MBO between 2009 and 2022. The primary outcome was the stent patency. The secondary outcomes were technical and clinical success, adverse events (AEs) of each technique, and independent risk factors for stent dysfunction. Results: In all, 115 patients were divided into EUS-CDS (n = 56) and EUS-HGS (n = 59) groups. Among them, technical success was achieved in 98.2% of EUS-CDS and 96.6% of EUS-HGS groups. Furthermore, clinical success was 96.4% in EUS-CDS and 88.1% in EUS-HGS groups, without significant difference (p = 0.200). The mean duration of stent patency for EUS-CDS was 770.3 days while that for EUS-HGS was 164.9 days (p = 0.010). In addition, the only independent risk factor for stent dysfunction was systematic treatment after EUS-BD [hazard ratio and 95% confidence interval 0.238 (0.066-0.863), p = 0.029]. The incidence of stent dysfunction of EUS-HGS was higher than EUS-CDS (35.1% versus 18.2%, 0.071), despite no significant differences even in late AEs. Conclusion: In distal MBO, EUS-CDS may be better than EUS-HGS with longer stent patency and fewer AEs. Furthermore, systematic treatment after EUS-BD is recommended for the improvement of stent patency.

Convolutional neural network model for automatic recognition and classification of pancreatic cancer cell based on analysis of lipid droplet on unlabeled sample by 3D optical diffraction tomography.

INTRODUCTION: Pancreatic cancer cells generally accumulate large numbers of lipid droplets (LDs), which regulate lipid storage. To promote rapid diagnosis, an automatic pancreatic cancer cell recognition system based on a deep convolutional neural network was proposed in this study using quantitative images of LDs from stain-free cytologic samples by optical diffraction tomography. METHODS: We retrieved 3D refractive index tomograms and reconstructed 37 optical images of one cell. From the four cell lines, the obtained fields were separated into training and test datasets with 10,397 and 3,478 images, respectively. Furthermore, we adopted several machine learning techniques based on a single image-based prediction model to improve the performance of the computer-aided diagnostic system. RESULTS: Pancreatic cancer cells had a significantly lower total cell volume and dry mass than did normal pancreatic cells and were accompanied by greater numbers of lipid droplets (LDs). When evaluating multitask learning techniques utilizing the EfficientNet-b3 model through confusion matrices, the overall 2-category accuracy for cancer classification reached 96.7 %. Simultaneously, the overall 4-category accuracy for individual cell line classification achieved a high accuracy of 96.2 %. Furthermore, when we added the core techniques one by one, the overall performance of the proposed technique significantly improved, reaching an area under the curve (AUC) of 0.997 and an accuracy of 97.06 %. Finally, the AUC reached 0.998 through the ablation study with the score fusion technique. DISCUSSION: Our novel training strategy has significant potential for automating and promoting rapid recognition of pancreatic cancer cells. In the near future, deep learning-embedded medical devices will substitute laborious manual cytopathologic examinations for sustainable economic potential.

Gallbladder perforation in acute acalculous vs. calculous cholecystitis: a retrospective comparative cohort study with 10-year single-center experience.

BACKGROUND: Gallstones are a well-known risk factor for acute cholecystitis. However, their role as a risk factor for gallbladder perforation (GBP) remains unclear. Therefore, this study aimed to determine the effect of gallstones on the development of GBP. MATERIALS AND METHODS: This large-scale retrospective cohort study enroled consecutive patients who underwent cholecystectomy for acute cholecystitis. The primary endpoint was the role of gallstones as a risk factor for developing GBP. Secondary endpoints included the clinical characteristics of GBP, other risk factors for GBP, differences in clinical outcomes between patients with acalculous cholecystitis (AC) and calculous cholecystitis (CC), and the influence of cholecystectomy timing. RESULTS: A total of 4497 patients were included in this study. The incidence of GBP was significantly higher in the AC group compared to the CC group (5.6% vs. 1.0%, P <0.001). However, there were no differences in ICU admission and hospital stay durations. The incidence of overall complications was significantly higher in the AC group than in the CC group (2.2% vs. 1.0%, P <0.001). Patients with AC had a higher risk of developing GBP than those with CC (odds ratio, 5.00; 95% CI, 2.94-8.33). In addition, older age (≥60 years), male sex, comorbidities, poor performance status, and concomitant acute cholangitis were associated with the development of GBP. Furthermore, the incidence of GBP was significantly higher in the delayed cholecystectomy group than in the early cholecystectomy group (2.0% vs. 0.9%, P <0.001). CONCLUSIONS: AC is a significant risk factor for GBP. Furthermore, early cholecystectomy can significantly reduce GBP-related morbidity and mortality.

Comparison between three types of needles for endoscopic ultrasound-guided tissue acquisition of pancreatic solid masses: a multicenter observational study.

It is debatable which needle has clear superiority of diagnostic performance in endoscopic ultrasound (EUS)-guided fine needle biopsy (FNB) of solid pancreatic masses. This study aimed to compare the performance of three needles and determine the variables that affect diagnostic accuracy. From March 2014 to May 2020, 746 patients with solid pancreatic masses who underwent EUS-FNB using three types of needles (Franseen needle, Menghini-tip needle, and Reverse-bevel needle) were retrospectively reviewed. Multivariate analysis using a logistic regression model was used to identify factors related to diagnostic accuracy. There were significant differences between the groups regarding the procurement rate of the histologic and optimal quality cores (Franseen vs. Menghini-tip vs. Reverse-bevel: 98.0% [192/196] vs. 85.8% [97/113] vs. 91.9% [331/360], P < 0.001 and 95.4% [187/196] vs. 65.5% [74/113] vs. 88.3% [318/360], P < 0.001, respectively). The sensitivity and accuracy using histologic samples were 95.03% and 95.92% for Franseen, 82.67% and 88.50% for Menghini-tip, and 82.61% and 85.56% for Reverse-bevel needles, respectively. In direct comparison between the needles using histologic samples, the Franseen needle showed significantly superior accuracy than the Menghini-tip (P = 0.018) and Reverse-bevel needles (P < 0.001). Multivariate analysis indicated that tumor size ≥ 2 cm (odds ratio [OR] 5.36, 95% confidence interval [CI] 3.40-8.47, P < 0.001) and fanning technique (OR 1.70, 95% CI 1.00-2.86, P = 0.047) were significantly associated with an accurate diagnosis. EUS-FNB using the Franseen needle enables the acquisition of a larger and more adequate histologic core tissue and achieves an accurate histological diagnosis when using the fanning technique.

EUS-guided tissue acquisition using a novel torque technique is comparable with that of the fanning technique for solid pancreatic lesions: A multicenter randomized trial.

BACKGROUND: The torque and fanning techniques allow for multiple areas within pancreatic lesions to be targeted using different maneuvers and can, hence, enhance diagnostic outcomes. We compared the diagnostic performance of endoscopic ultrasound-guided fine-needle biopsy (EUS-FNB) for pancreatic masses using the torque and fanning techniques. METHODS: This multicenter randomized trial enrolled a total of 160 consecutive patients who underwent EUS-FNB for solid pancreatic tumors using either the torque or fanning technique. Three passes were permitted for each lesion, and the technique sequence was randomly assigned as either torque first or fanning first with the standard technique as a reference. RESULTS: The median quality score of the histological samples was significantly higher in the torque and fanning group than in the standard group (p < .001). Furthermore, the torque technique provided improved sensitivity of 93.38% and accuracy of 94.30%. The standard technique provided diagnostic sensitivity of 68.84% and accuracy of 72.96%, while the fanning technique showed sensitivity of 91.85% and accuracy of 93.04%. CONCLUSIONS: The new torque technique enables the acquisition of better-quality samples and can potentially increase the diagnostic outcomes in the EUS-FNB of pancreatic solid masses, with the same recommendations as those for the fanning technique.

Covered versus uncovered double bare self-expandable metal stent for palliation of unresectable extrahepatic malignant biliary obstruction: a randomized controlled multicenter trial.

BACKGROUND AND AIMS: In a recent randomized controlled trial, a double bare metal stent (DBS) showed better stent patency than single-layer metal stents. However, clear evidence comparing the efficacy of uncovered (UCDBS) and partially covered (PCDBS) DBSs for distal malignant biliary obstruction (MBO) is lacking. Therefore, we compared the clinical outcomes including stent patency of UCDBSs versus PCDBSs. METHODS: A multicenter, randomized study was performed in patients with distal MBO. The primary endpoint was stent patency. Secondary endpoints were the proportion of patients with patent stents at 6 months, risk factors for stent dysfunction, overall survival, technical and clinical success rates of stent placement, and other adverse events (AEs). RESULTS: Among 258 included patients, 130 were randomly assigned to the PCDBS group and 128 to the UCDBS group. The mean duration of stent patency of the PCDBS (421.2 days; 95% confidence interval [CI], 346.7-495.7) was longer than that of the UCDBS (377.4 days; 95% CI, 299.7-455.0), although total stent dysfunction and stent dysfunction within 6 months were not different between groups. Multivariate analysis indicated that chemotherapy after stent placement was a significant factor for overall survival (hazard ratio, .570; 95% CI, .408-.796) and had a marginal impact on stent patency (hazard ratio, 1.569; 95% CI, .923-2.667). There were no remarkable differences in AEs, including pancreatitis, cholecystitis, and stent migration, between the 2 groups. CONCLUSIONS: The use of PCDBSs compared with UCDBSs in patients with distal MBO has unclear benefits regarding stent patency and overall survival, although PCDBSs have a lower rate of tumor ingrowth. (Clinical trial registration number: NCT02937246.).

Ursodeoxycholic acid inhibits epithelial-mesenchymal transition, suppressing invasiveness of bile duct cancer cells: An in vitro study.

Epithelial-mesenchymal transition (EMT) features are associated with pathological severity in the progression and metastasis of various cancer types, including bile duct cancer (BDC). Our previous study demonstrated that ursodeoxycholic acid (UDCA) blocked the EGFR-MAPK signaling pathway and inhibited the invasion of BDC cells. The present study was performed to determine whether UDCA inhibits EMT and promotes the expression of E-cadherin to inhibit the invasion and aggressiveness of BDC. In addition, the present study aimed to confirm that the primary mechanism of inhibition of EMT by UDCA is related to the EGFR axis. Human extrahepatic BDC cells were cultured. The effect of UDCA on cell proliferation was evaluated using MTT assays. A cell death ELISA kit was used to measure apoptosis, and western blot assays or immunofluorescence staining assays measured the expression levels of various target proteins. The mRNA expression of Slug and ZEB1 was evaluated via reverse transcription-quantitative PCR. The invasiveness of BDC cells was estimated by invasion assays and western blot assays for focal adhesion kinase (FAK). UDCA inhibited the proliferation of BDC cells as effectively as gefitinib (an EGFR inhibitor), and the combination of UDCA and gefitinib revealed an additive effect on the proliferation of cells. UDCA and gefitinib induced apoptosis, and the combination of UDCA and gefitinib demonstrated an additive effect on apoptosis in BDC cells. UDCA restored the E-cadherin expression inhibited by EGF and suppressed N-cadherin expression increased by EGF as effectively as gefitinib. UDCA suppressed the Slug and ZEB1 mRNA expression induced by EGF in BDC cells. UDCA suppressed the invasiveness of BDC cells and FAK expression linked to the invasiveness of BDC. In conclusion, UDCA enhanced E-cadherin expression and suppressed N-cadherin expression through inhibition of the EGF-EGFR axis, contributing to the inhibition of EMT and invasiveness in BDC cells. Therefore, UDCA may be applied as an adjuvant or palliative antineoplastic agent and as a therapeutic option to enhance the effect of other chemotherapeutics.

Long-term outcomes and predictors of adverse events of EUS-guided hepatico-gastrostomy for malignant biliary obstruction: Multicenter, retrospective study.

BACKGROUND AND AIMS: Endoscopic ultrasound (EUS)-guided hepaticogastrostomy (HGS) may be a feasible and useful alternative in patients with malignant biliary obstruction (MBO) after failed endoscopic retrograde cholangiopancreatography (ERCP). To date, the risk factors for adverse events (AEs) and long-term outcomes of EUS-HGS have not been fully explored according to stent type. Therefore, we evaluated potential risk factors for AEs and long-term outcomes of EUS-HGS. METHODS: In total, 120 patients who underwent EUS-HGS were retrospectively reviewed. A multivariate analysis through Cox proportional hazard and logistic regression model was used to identify the risk factors for stent dysfunction and AEs, respectively. Stent patency and patient survival were evaluated using Kaplan-Meier plots with a log-rank test for each stent. RESULTS: The technical and clinical success rates were 96.2% (102/106) and 83.0% (88/106). The median duration of stent patency was longer in self-expandable metal stents (SEMS) compared to plastic stents (PS) (158 vs. 108 days). Kaplan-Meier analysis indicated that the type of stent was not associated with stent patency (Hazard ratios [HR] 0.997, 95% confidence interval [CI] [0.525-1.896]) or overall survival. In addition, multivariate analysis indicated that hilar MBO significantly associated with stent dysfunction (HR, 2.340; 95% CI, 1.028-5.326, p = 0.043) and late AEs. CONCLUSIONS: Given the lower incidence of AEs and better long-term outcomes of EUS-HGS, it can be considered a safe alternative to ERCP or percutaneous approaches regardless of which stent is used. Furthermore, hilar MBO was established as a potential risk factor for stent dysfunction and late AEs.

Effect of prophylactic endoscopic clipping for prevention of delayed bleeding after endoscopic papillectomy for ampullary neoplasm: a multicenter randomized trial.

BACKGROUND : Endoscopic clip placement is technically challenging using a duodenoscope, limiting their application for treatment of bleeding after endoscopic papillectomy. This study evaluated the efficacy of newly designed clips to prevent bleeding after endoscopic papillectomy. METHODS : Patients (n = 80) with suspected benign adenomas on the major papilla who were scheduled for endoscopic papillectomy with or without clipping were randomized. A new duodenoscope-compatible clip capable of being rotated, reopened, and repeatedly repositioned was used. The primary end point was incidence of delayed bleeding. RESULTS : The clipping procedure was successful in all patients. The incidence of delayed bleeding was nonsignificantly higher in the no-clipping group than in the clipping group (31.6 % [95 % confidence interval (CI) 19.1-47.5] vs. 15.0 % [95 %CI 7.1-29.1]). The incidence of post-endoscopic retrograde cholangiopancreatography pancreatitis did not differ significantly between the groups (clipping vs. no-clipping: 17.5 % [95 %CI 8.7-31.9] vs. 5.3 % [95 %CI 1.5-17.3]), and all cases were mild. CONCLUSIONS : Placement of the newly designed rotatable clip was technically feasible and tended to have a protective effect by preventing delayed bleeding after endoscopic papillectomy, although statistical significance was not reached.

Minimal and Maximal Extent of Band Ligation for Acute Variceal Bleeding during the First Endoscopic Session.

BACKGROUND/AIMS: The appropriate number of band ligations during the first endoscopic session for acute variceal bleeding is debatable. We aimed to compare the technical aspects of endoscopic variceal ligation (EVL) in patients with variceal bleeding according to the number of bands placed per session. METHODS: We retrospectively reviewed multicenter data from patients who underwent EVL for acute variceal bleeding. Patients were classified into minimal EVL (targeting only the foci with active bleeding or stigmata of recent bleeding) and maximal EVL (targeting potential bleeding sources in addition to the aforementioned targets) groups. The primary endpoint was 5-day treatment failure. The secondary endpoints were 30-day rebleeding, 30-day mortality, and intraprocedural adverse events. RESULTS: Minimal EVL was associated with lower rates of hypoxia and shock during EVL than maximal EVL (hypoxia, 0.9% vs 2.9%; shock, 1.3% vs 3.4%). However, treatment failure was higher in the minimal EVL group than in the maximal EVL group (odds ratio, 1.60; 95% confidence interval, 1.06 to 2.41). Age ≥60 years, Model for End-Stage Liver Disease score ≥15, Child-Turcotte-Pugh classification C, presence of hepatocellular carcinoma, and systolic blood pressure <90 mm Hg at initial presentation were also associated with treatment failure. In contrast, 30-day rebleeding and 30-day mortality did not differ between the minimal and maximal EVL groups. CONCLUSIONS: Given that minimal EVL was associated with a high risk of treatment failure, maximal EVL may be a better option for variceal bleeding. However, the minimal EVL strategy should be considered in select patients because it does not affect 30-day rebleeding and mortality.

Current status of endoscopic management of cholecystitis.

Laparoscopic cholecystectomy remains the standard treatment for acute cholecystitis (AC) although it is always not suitable for patients who are poor candidates for surgery. Recently, endoscopic gallbladder (GB) drainage was found to be a potentially revolutionary alternative for cholecystectomy for the control of symptoms, definitive treatment, or bridging therapy until surgery is possible. Two endoscopic methods have been established using either the trans-mural or trans-papillary drainage approach. Endoscopic ultrasound-guided GB drainage (EUS-GBD; trans-mural approach) is a novel technique that allows stent placement between the GB and duodenum or stomach via fistula track, effectively enabling GB drainage. For endoscopic trans-papillary GB drainage (ETGBD; trans-papillary approach), attempts of selective cannulation to the cystic duct should be made to place the stent in the same manner as an endoscopic retrograde cholangiopancreatography. In comparison, EUS-GBD has higher clinical success and lower recurrence rates than ETGBD due to the use of larger-caliber stents, which allow for effective drainage when performed by skilled practitioners at high-volume centers. Advantages of ETGBD over EUS-GBD include more affordable costs and physiologic drainage, which preserves naive anatomy for possible future cholecystectomy. Although the field of endoscopic treatment for AC is rapidly advancing, important questions regarding which method improves clinical outcomes and safety more effectively remain unaddressed. Herein, the current status of endoscopic treatment for AC, including a technical review on clinical outcomes, adverse events, and advantages and disadvantages of each technique are reviewed, as well as other future prospects.

Pre- and post-procedure risk prediction models for post-endoscopic retrograde cholangiopancreatography pancreatitis.

BACKGROUND: Post-endoscopic retrograde cholangiopancreatography pancreatitis (PEP) is the most common serious adverse event. Given recent endoscopic advances, we aimed to develop and validate a risk prediction model for PEP using the latest clinical database. METHODS: We analyzed the data of patients with naïve papilla who underwent endoscopic retrograde cholangiopancreatography (ERCP). Pre-ERCP and post-ERCP risk prediction models for PEP were developed using logistic regression analysis. Patients were classified into low- (0 points), intermediate- (1-2 points), and high-risk (≥ 3 points) groups according to point scores. RESULTS: We included 760 and 735 patients in the derivation and validation cohorts, respectively. The incidence of PEP was 5.5% in the derivation cohort and 3.9% in the validation cohort. Age ≤ 65 (1 point), female sex (1 point), acute pancreatitis history (2 points), malignant biliary obstruction (2 points [pre-ERCP model] or 1 point [post-ERCP model]), and pancreatic sphincterotomy (2 points, post-ERCP model only) were independent risk factors. In the validation cohort, the high-risk group (≥ 3 points) had a significantly higher risk of PEP compared to the low- or intermediate-risk groups under the post-ERCP risk prediction model (low: 2.0%; intermediate: 3.4%; high: 18.4%), while there was no significant between-group difference under the pre-ERCP risk prediction model (low: 2.2%; intermediate: 3.8%; high: 6.9%). CONCLUSIONS: We developed and validated pre-ERCP and post-ERCP risk prediction models. In the latter, the high-risk group had a higher risk of PEP development than the low- or intermediate-risk groups. Our study findings will help clinicians stratify patient risk for the development of PEP.

Ursodeoxycholic acid shows antineoplastic effects in bile duct cancer cells via apoptosis induction; p53 activation; and EGFR-ERK, COX-2, and PI3K-AKT pathway inhibition.

Unlike in normal cells, ursodeoxycholic acid (UDCA) causes apoptosis rather than protection in cancer cells. Aim of this study was to demonstrate whether UDCA actually inhibits proliferation and induces apoptosis in bile duct cancer cells; the effect of UDCA on the expression of COX-2, PI3K/AKT, ERK, and EGFR; how UDCA affects cancer cell invasiveness and metastasis, since these effects are not established in bile duct cancer cells. SNU-245 cells (human extrahepatic bile duct cancer cells) were cultured. MTT assays were performed to evaluate the effect of UDCA on the cell proliferation. A cell death detection enzyme-linked immunosorbent assay and a caspase-3 activity assay were used to determine apoptosis. Western blot analysis measured expression levels of various proteins. The invasiveness of the cancer cells was evaluated by invasion assay. In cultured bile duct cancer cells, UDCA suppressed cell proliferation in bile duct cancer cells by inducing apoptosis and p53 activation, blocking deoxycholic acid (DCA)-induced activated EGFR-ERK signaling and COX-2, inhibiting DCA-induced activated PI3K-AKT signaling, and suppressing the invasiveness of bile duct cancer cells. In addition, a MEK inhibitor impaired UDCA-induced apoptosis in bile duct cancer cells. UDCA has antineoplastic and apoptotic effects in bile duct cancer cells. Thus, UDCA could be a chemopreventive agent in patients with a high risk of cancer, and/or a therapeutic option that enhances other chemotherapeutics.

[Clinical and Technical Guideline for Endoscopic Ultrasound-guided Tissue Acquisition of Pancreatic Solid Tumor: Korean Society of Gastrointestinal Endoscopy].

Endoscopic ultrasound (EUS)-guided tissue acquisition of pancreatic solid tumor requires a strict recommendation for its proper use in clinical practice because of its technical difficulty and invasiveness. The Korean Society of Gastrointestinal Endoscopy appointed a Task Force to draft clinical practice guidelines for EUS-guided tissue acquisition of pancreatic solid tumor. The strength of recommendation and the level of evidence for each statement were graded according to the Minds Handbook for Clinical Practice Guideline Development 2014. The committee, comprising a development panel of 16 endosonographers and an expert on guideline development methodology, developed 12 evidence-based recommendations in eight categories intended to help physicians make evidence- based clinical judgments with regard to the diagnosis of pancreatic solid tumor. This clinical practice guideline discusses EUS-guided sampling in pancreatic solid tumor and makes recommendations on circumstances that warrant its use, technical issues related to maximizing the diagnostic yield (e.g., needle type, needle diameter, adequate number of needle passes, sample obtaining techniques, and methods of specimen processing), adverse events of EUS-guided tissue acquisition, and learning-related issues. This guideline was reviewed by external experts and suggests best practices recommended based on the evidence available at the time of preparation. This guideline may not be applicable for all clinical situations and should be interpreted in light of specific situations and the availability of resources. It will be revised as necessary to cover progress and changes in technology and evidence from clinical practice.

Clinical and Technical Guideline for Endoscopic Ultrasound (EUS)-Guided Tissue Acquisition of Pancreatic Solid Tumor: Korean Society of Gastrointestinal Endoscopy (KSGE).

Endoscopic ultrasound (EUS)-guided tissue acquisition of pancreatic solid tumor requires a strict recommendation for its proper use in clinical practice because of its technical difficulty and invasiveness. The Korean Society of Gastrointestinal Endoscopy (KSGE) appointed a task force to draft clinical practice guidelines for EUS-guided tissue acquisition of pancreatic solid tumor. The strength of recommendation and the level of evidence for each statement were graded according to the Minds Handbook for Clinical Practice Guideline Development 2014. The committee, comprising a development panel of 16 endosonographers and an expert on guideline development methodology, developed 12 evidence-based recommendations in eight categories intended to help physicians make evidence-based clinical judgments with regard to the diagnosis of pancreatic solid tumor. This clinical practice guideline discusses EUS-guided sampling in pancreatic solid tumor and makes recommendations on circumstances that warrant its use, technical issues related to maximizing the diagnostic yield (e.g., needle type, needle diameter, adequate number of needle passes, sample obtaining techniques, and methods of specimen processing), adverse events of EUS-guided tissue acquisition, and learning-related issues. This guideline was reviewed by external experts and suggests best practices recommended based on the evidence available at the time of preparation. This guideline may not be applicable for all clinical situations and should be interpreted in light of specific situations and the availability of resources. It will be revised as necessary to cover progress and changes in technology and evidence from clinical practice.