A Japanese Prospective, Multicenter Study of Colonic Stenting for Palliation Using a High Axial Force Self-Expandable Metal Stent for Malignant Large Bowel Obstruction in 200 Patients.

Evidence of the efficacy and safety of colorectal stent placement for palliation remains insufficient. This single-arm, prospective, multicenter study with a WallFlex enteral colonic stent included 200 consecutive patients with malignant large bowl obstruction in the palliation cohort. The technical and clinical success, as well as stent patency and complications as short-term (≤7 days) and long-term (>7 days) outcomes, of high axial force self-expandable metal stent (SEMS) placement was evaluated. The technical and clinical success rates were 98.5% and 94.5%, respectively. Non-recurrent colorectal obstruction at 1 year was 63.9%, and 71.2% of the patients remained free of recurrent colorectal obstruction until death or the last follow-up. Fifty-six patients (28.0%) received chemotherapy, and five patients were administered bevacizumab after stent placement. The overall complication rate was 47%, including four (2.0%) early-onset and ten (5.0%) late-onset perforations, mostly due to stent-edge injury. Only the use of a long SEMS was a risk factor for perforation. In conclusion, endoscopic colorectal stenting using high axial force SEMS is an effective and safe procedure for palliation in patients with malignant colorectal obstruction. However, care should be taken to avoid perforation at the stent edge when using a long SEMS.

Preprocedural control of nutritional status score and prediction of early death after percutaneous endoscopic gastrostomy.

Background and Aim: Percutaneous endoscopic gastrostomy (PEG) is often associated with early mortality. We therefore investigated factors associated with early death after PEG. Methods: The present study comprised patients who had undergone PEG between April 2014 and March 2020. Patients were divided into two groups: an early mortality group who died within 1 month of PEG, and a non-mortality group whose clinical course could be followed for more than 1 month after the procedure. Patient background, hematological data, and procedural duration were compared between groups. Results: Univariate analysis identified older age, high blood urea nitrogen (BUN), low prognostic nutritional index (PNI), and high controlling nutritional status (CONUT) score as factors associated with early death after PEG. In multivariate analysis, high CONUT score remained an independent prognostic factor (P = 0.0035). Conclusion: A high CONUT score may be a prognostic factor for early mortality after PEG.

Clinical and endoscopic features of metachronous gastric cancer with possible lymph node metastasis after endoscopic submucosal dissection and Helicobacter pylori eradication.

BACKGROUND: Several studies have reported the metachronous gastric cancers (MGCs) with possible lymph node metastasis (LNM) after endoscopic submucosal dissection (ESD) and Helicobacter pylori (H. pylori) eradication in which a curative ESD had not been achieved. There have been no published reports of evaluations of the features of patients with MGC with possible LNM after ESD and H. pylori eradication. METHODS: We identified 264 patients with 369 MGCs after H. pylori eradication among the 4354 patients with 5059 early gastric cancers (EGCs) who underwent ESD between 1999 and 2017 and divided them into two groups: patients with MGCs with possible LNM (Group I) and patients with MGCs undergone curative ESD (Group II). We retrospectively compared the features of patients with MGCs and patients with EGCs at index ESD in the two groups. RESULT: Group I consisted of 20 patients with 21 MGCs, and Group II consisted of 244 patients with 348 MGCs. Group I lesions were significantly more common in the posterior wall than in the lesser curvature (odds ratio [OR] = 3.97; 95% confidence intervals [CI] 1.20-13.10). Development of Group I was significantly more common in patients with a body mass index (BMI) < 19.0 kg/m2 than in patients with a BMI ≥ 19.0 kg/m2 at index ESD (OR = 4.44; 95% CI 1.30-15.20). CONCLUSIONS: During surveillance endoscopy after gastric ESD and H. pylori eradication, the posterior wall should be carefully examined to detect MGCs early. Lower BMI may be associated with the development of MGCs with possible LNM.

A follow-up questionnaire survey 2022 on radiation protection among 464 medical staff from 34 endoscopy-fluoroscopy departments in Japan.

Objectives: We surveyed and reported low protective equipment usage and insufficient knowledge among endoscopy-fluoroscopy departments in Japan in 2020. Two years later, we conducted a follow-up survey of doctors, nurses, and technologists in Japan. Methods: We conducted a questionnaire survey on radiation protection from May to June 2022. The participants were medical staff, including doctors, nurses, and radiological and endoscopy technicians in endoscopy-fluoroscopy departments. The questionnaire included 17 multiple-choice questions divided into three parts: background, equipment, and knowledge. Results: We surveyed 464 subjects from 34 institutions. There were 267 doctors (58%), 153 nurses (33%), and 44 technologists (9%). The rate of wearing a lead apron was 98% in this study. The rates of wearing a thyroid collar, lead glasses, and radiation dosimeter were 27%, 35%, and 74%, respectively. The trend of the protective equipment rate was similar to that of our previous study; however, radiation dosimetry among doctors was still low at 58%. The percentage of subjects who knew the radiation exposure (REX) dose of each procedure was low at 18%. Seventy-six percent of the subjects attended lectures on radiation protection, and 73% knew about the three principles of radiation protection; however, the concept of diagnostic reference levels was not well known (18%). Approximately 60% of the subjects knew about the exposure dose increasing cancer mortality (63%) and the 5-year lens REX limit (56%). Conclusions: There was some improvement in radiation protection equipment or education, but relatively little compared to the 2020 survey of endoscopy departments.

Radiation dose and factors related to exceeding the diagnostic reference level in 496 transnasal ileus tube placement procedures from the REX-GI study.

OBJECTIVE: We aimed to examine the factors contributing to radiation exposure exceeding the DRL of the transnasal ileus tube placement in this post hoc analysis from the cohort of the REX-GI study. METHODS: Patients with transnasal ileus tubes were enrolled in the rex-gi study from may 2019 to december 2020. We investigated the endoscope insertion time (min), procedure time (min), tube insertion length (cm), fluoroscopy time (FT: min), air kerma at the patient entrance reference point (Ka.r: mGy), and air kerma-area product (PKA: Gycm2). The third quartile value of the PKA value was calculated as the diagnostic reference level (DRL) value. We explored the factors associated with radiation exposure exceeding the DRL. RESULTS: In the REX-GI study, 496 patients who underwent transnasal ileus tube placement were enrolled. The median age of the patients was 71 years. The median endoscopy insertion time, procedure time, and tube insertion length were 6 min, 20 min, and 170 cm, respectively. The third quartile/median FT, Ka.r, and PKA were 18/11.9 min, 99.2/54.4 mGy, and 46.9/28 Gycm2, respectively. The third quartile value of PKA (47 Gycm2) was set as the DRL value. There were differences in distribution by the hospital. Compared with procedures under the DRL, the FT (19 vs 10 min), procedure time (25 vs 18 min), and tube insertion length (185 vs 165 cm) were significantly longer for procedures above the DRL. CONCLUSION: We report the DRL for transnasal ileus tube placement in Japan. A longer procedure time and tube insertion length may be associated with DRL exceedance. ADVANCES IN KNOWLEDGE: Transnasal ileus tube placement under fluoroscopy guidance is a standard clinical procedure for bowel obstruction. However, the appropriate radiation dose level has not yet been established.We report the (DRL) for transnasal ileus tube placement in Japan. A longer procedure time and tube insertion length may be associated with DRL exceedance.

Gastroduodenal Stenting with a Flexible Stent Demonstrates Favorable Clinical Effectiveness despite Gradual Expansion: A Multicenter Prospective Study.

AIMS: This study aimed to evaluate the effectiveness and safety of stenting with a flexible braided self-expandable metal stent (SEMS) for unresectable malignant gastric outlet obstruction (GOO). METHODS: Palliative stenting was prospectively carried out at seven university hospitals between October 2017 and August 2020. All procedures were performed using a flexible branded SEMS of the same brand. The primary endpoint was clinical success rate at 7 days after stenting. Secondary endpoints were procedural success rate, adverse events, recurrent gastric outlet obstruction (RGOO), and patient survival time. RESULTS: Sixty patients were enrolled. The procedural and clinical success rates were 100% and 90%, respectively. RGOO occurred in 15 cases (25%). Adverse events other than RGOO were found in seven cases (12%). The 50% survival time was 75.5 days (range: 52-97 days). Median expansion rates at 1, 3, and 7 days after stenting were 55%, 65%, and 75%, respectively. CONCLUSIONS: A flexible braided stent woven with relatively thin wires was used for malignant GOO. Despite a gradual expansion with slightly lower expansile force, the stent functioned sufficiently well and showed favorable results. Clinical Trials Registry ID: UMIN000029496.

Medical radiation exposure during gastrointestinal enteral metallic stent placement: Post hoc analysis of the REX-GI study.

Background and Aim: Recently, the use of various endoscopic procedures performed under X-ray fluoroscopy guidance has increased. With the popularization of such procedures, diagnostic reference levels (DRLs) have been widely accepted as the global standard for various procedures with ionizing radiation. The Radiation Exposure from Gastrointestinal Fluoroscopic Procedures (REX-GI) study aimed to prospectively collect actual radiation exposure (RE) data and establish DRLs in gastrointestinal endoscopy units. In this post hoc analysis of the REX-GI study, we established DRLs for each disease site by analyzing cases of gastrointestinal enteral metallic stent placement. Methods: The REX-GI study was a multicenter, prospective observational study conducted to collect actual RE data during gastrointestinal enteral metallic stent placement. To establish DRL values for three disease sites, namely the esophagus, gastroduodenum, and colon, we examined fluoroscopy time (FT; min), number of X-ray images, air kerma at the patient entrance reference point (K a,r; mGy), and the air kerma-area product (P KA; Gy cm2) during enteral metallic stent placement. Results: Five-hundred and twenty-three stenting procedures were performed. The DRL values of FT (min) and the number of X-ray images for the esophagus/gastroduodenum/colon were 9/16/18 min and 9/15/11 min, respectively. Furthermore, the DRL values of K a,r and P KA for each disease site were 43.3/120/124 mGy and 10.3/36.6/48.4 Gy cm2, respectively. Among the procedures, esophageal stents were significantly associated with the lowest values (P < 0.001). Conclusion: The characteristics of RE vary according to disease site among gastrointestinal enteral metallic stent placements. Thus, it is desirable to set DRL values based on the disease site.

How to successfully administer palliative treatment with a stent for malignant gastric outlet obstruction?

Although endoscopic stenting (ES) has been widely used as a less-invasive palliation method for malignant gastric outlet obstruction (GOO), recent reports have highlighted issues related to the procedure. For successful treatment, various aspects must be assessed before considering the practices. First, it is necessary to eliminate cases with contraindications such as coexistence of distal small-bowel obstruction or perforation. Other factors potentially related to clinical failure (i.e., peritoneal carcinomatosis) may require consideration but remain controversial. ES has better short-term outcomes than surgical gastrojejunostomy (GJ). GJ has recently been considered preferable in cases with longer life expectancy because of superior sustainability. Various types of stents are now commercially available, but their ideal structure and mechanical properties have not yet been clarified. Covered metal stent may reduce stent obstruction but is prone to increase stent migration, and its significance remains uncertain. Subsequent chemotherapy after stenting should be considered, as it is expected to prolong patient survival without increasing the risk of adverse events. Furthermore, it may be helpful in preventing tumor ingrowth. In cases with GOO combined with biliary obstruction, biliary intervention is often difficult. Recently, endoscopic ultrasound-guided biliary drainage (EUS-BD) has been widely used as an alternative procedure for endoscopic transpapillary biliary drainage (ETBD). Despite the lack of consensus as to whether ETBD or EUS-BD is preferred, EUS-BD is useful as a salvage technique for cases where ETBD is difficult. To perform stent placement successfully, it is important to pay attention to the above points; however, many remaining issues need to be clarified in the future.

The effect of antithrombotic drug use on delayed bleeding with esophageal endoscopic resection.

BACKGROUND AND AIM: Whether antithrombotic drugs increase the risk of post-esophageal endoscopic resection bleeding is unknown. This study examined the effect of antithrombotic drugs, aspirin, thienopyridine, direct oral anticoagulants (DOAC), and warfarin, on post-esophageal endoscopic resection bleeding. METHODS: We enrolled 957 patients (1202 esophageal tumors) treated with endoscopic resection and classified them based on antithrombotic drug use as no use, aspirin, thienopyridine, DOAC, and warfarin. Patients using antiplatelet drugs (i.e. aspirin and thienopyridine) were further sub-classified based on their continued or discontinued use before endoscopic resection. The bleeding rates were compared between these groups to assess the effects of antithrombotic drug use and interruption of antiplatelet therapy on post-esophageal endoscopic resection bleeding. RESULTS: The post-endoscopic resection bleeding rate was 0.3% (95% CI, 0.1-1) in the group without antithrombotic drug use, 4.5% (95% CI, 0.1-23) in the aspirin-continued group, 2.9% (95% CI, 0.1-15) in the aspirin-discontinued group, 0% (95% CI, 0-78) in the replaced thienopyridine with aspirin group, 0% (95% CI, 0-26) in the thienopyridine-discontinued group, 13% (95% CI, 1.6-38) in the DOAC group, and 0% (95% CI, 0-45) in the warfarin group. The post-endoscopic resection bleeding rate in the DOAC group was significantly higher than that in the group without antithrombotic drugs (P = 0.003). The post-endoscopic resection bleeding rates did not differ between the other groups. CONCLUSIONS: Our results suggest that discontinuing aspirin is not necessary for esophageal endoscopic resection while we must be careful regarding DOAC.

[Idiopathic esophageal submucosal hematoma during antithrombotic therapy for essential thrombocythemia].

A 73-year-old woman was hospitalized with sudden chest pain and hematemesis. Chest computed tomography and upper gastrointestinal endoscopy revealed an idiopathic submucosal hematoma from the cervical esophagus to the esophagogastric mucosal junction. Idiopathic esophageal submucosal hematoma is often prone to a bleeding tendency of an underlying disorder. The patient had a history of essential thrombocythemia (ET) and was taking aspirin. She successfully recovered after aspirin discontinuation and conservative treatment; however, died of cardiopulmonary arrest in the ward on day 9 of hospitalization. The autopsy revealed that the cause of death was pulmonary thromboembolism. This is the first report of ET with submucosal hematoma of the esophagus. The possibility of an esophageal submucosal hematoma should be considered when patients with ET complain of chest pain since ET and treatment with aspirin are considered risk factors for bleeding. Additionally, close attention should be focused on the risk of developing thrombosis if a patient with myeloproliferative neoplasm is required to discontinue antithrombotic therapy due to a bleeding event.

Diagnostic Reference Levels for Fluoroscopy-guided Gastrointestinal Procedures in Japan from the REX-GI Study: A Nationwide Multicentre Prospective Observational Study.

BACKGROUND: Diagnostic reference levels (DRLs) are required to optimize medical exposure. However, data on DRLs for interventional fluoroscopic procedures are lacking, especially in gastroenterology. This study aimed to prospectively collect currently used radiation doses and help establish national DRLs for fluoroscopy-guided gastrointestinal procedures in Japan. METHODS: This multicentre, prospective, observational study collected actual radiation dose data from endoscopic retrograde cholangiopancreatography (ERCP), interventional endoscopic ultrasound (EUS), balloon-assisted enteroscopy (BAE), enteral metallic stent placement, and enteral tube placement from May 2019 to December 2020. The study outcomes were fluoroscopy time (FT: min), air kerma at the patient entrance reference point (Ka,r: mGy), air kerma area product (PKA: Gycm2), and radiation dose rate (RDR: mGy/min). Additionally, the basic settings of fluoroscopy equipment and the factors related to each procedure were investigated. This study was registered in the UMIN Clinical Trial Registry (UMIN 000036525). FINDINGS: Overall, 12959 fluoroscopy-guided gastrointestinal procedures were included from 23 hospitals in Japan. For 11162 ERCPs, the median/third quartile values of Ka,r (mGy), PKA (Gycm2), and FT (min) were 69/145 mGy, 16/32 Gycm2, and 11/20 min, respectively. Similarly, these values were 106/219 mGy, 23/41 Gycm2 and 17/27 min for 374 interventional EUSs; 53/104 mGy, 16/32 Gycm2 and 10/15 min for 523 metallic stents; 56/104 mGy, 28/47 Gycm2, and 12/18 min for 599 tube placements; and 35/81 mGy, 16/43 Gycm2 and 7/15 min for 301 BAEs, respectively. For the overall radiation dose rate, the median/third quartile values of RDR were 5.9/9.4 (mGy/min). The RDR values at each institution varied widely. INTERPRETATION: This study reports the current radiation doses of fluoroscopy-guided gastrointestinal procedures expressed as DRL quantities. This will serve as a valuable reference for national DRL values. FUNDING: This work was supported by a clinical research grant from the Japanese Society of Gastroenterology.

Long-term outcomes of standardized colonic stenting using WallFlex as a bridge to surgery: Multicenter prospective cohort study.

OBJECTIVES: The oncological outcomes, especially high recurrence rate, of bridge-to-surgery (BTS) self-expandable metallic stent (SEMS) placement remain concerning, emphasizing the necessity of standardized SEMS placement. However, its impact on long-term BTS outcomes is unknown. We investigated the long-term outcomes of BTS colonic stenting using standardized SEMS placement. METHODS: This prospective, multicenter cohort study conducted at 46 hospitals in Japan (March 2012 to October 2013) included consecutive patients with stage II and III obstructive colorectal cancer managed with BTS SEMS placement. The SEMS placement technique was standardized by information dissemination among the participating hospitals. The primary outcome was overall survival (OS) after SEMS placement, and the secondary outcomes were relapse-free survival (RFS), recurrence, and short-term outcomes of SEMS placement and surgery. RESULTS: The 1-, 3-, and 5-year OS rates were 94.1%, 77.4%, and 67.4% (Kaplan-Meier), respectively, with high technical success (99.0%, 206/208) and low perforation (1.9%, 4/208) rates. The 1-, 3-, and 5-year RFS rates were 81.6%, 65.6%, and 57.9% (Kaplan-Meier), respectively, and the overall recurrence rate was 31.0% (62/200). The RFS rate was significantly poorer in patients with perforation (n = 4) than in those without perforation (n = 196) (log-rank P = 0.017); moreover, perforation was identified as an independent factor affecting RFS (hazard ratio 3.31; 95% confidence interval 1.03-10.71, multivariate Cox regression). CONCLUSION: This large, prospective, multicenter study revealed satisfactory long-term outcomes of BTS colonic stenting using a standardized SEMS insertion method, which might be specifically due to the reduced perforation rate. (UMIN000007953).

Risk of Pancreatitis Following Biliary Stenting With/Without Endoscopic Sphincterotomy: A Randomized Controlled Trial.

BACKGROUND & AIMS: The efficacy of endoscopic sphincterotomy (ES) before endoscopic transpapillary biliary drainage in preventing post-endoscopic retrograde cholangiopancreatography pancreatitis (PEP) has not been established. The aim of this study was to evaluate the effect of performing ES before biliary stent/tube placement on the occurrence of PEP. METHODS: Three hundred seventy patients with biliary stricture requiring endoscopic biliary stenting were enrolled and randomly allocated to the ES group (n = 185) or non-ES group (n = 185). All participants were followed up for 30 days after the procedure. The data and occurrence of adverse events were prospectively collected. The primary outcome measure of this study was the incidence of PEP within 2 days of initial transpapillary biliary drainage. Secondary outcome measures were the incidence of other adverse events related to biliary stent/tube placement. RESULTS: PEP occurred in 36 patients (20.6%) in the non-ES group and in 7 patients (3.9%) in the ES group (P < .001). The difference in the incidence of PEP between the 2 groups in the per-protocol population was 16.7% (95% confidence interval, 10.1%-23.3%), which was not within the noninferiority margin of 6%. Except for bleeding, the incidences of other adverse events were not significantly different between the groups. CONCLUSION: ES before endoscopic biliary stenting could have the preventive effect on the occurrence of PEP in patients with biliary stricture. University Hospital Medical Information Network Number, UMIN000025727.University Hospital Medical Information Network Clinical Trial Registry URL: https://www.umin.ac.jp/ctr/index.htm.

A prospective multicenter study of endoscopic ultrasound-guided fine needle biopsy using a 22-gauge Franseen needle for pancreatic solid lesions.

BACKGROUND AND AIM: While encouraging data of endoscopic ultrasound (EUS)-guided fine-needle biopsy (EUS-FNB) using a 22-gauge Franseen needle have been reported, large-scale data of per pass and quantitative analyses are still lacking. METHODS: This was a multicenter prospective study of EUS-FNB using the 22-gauge Franseen needle for a pancreatic solid lesion. Cytological and histological analyses per pass were evaluated and semi-quantitative analyses were performed on core tissue and blood contamination. Primary end-point was diagnostic accuracy per session. Prognostic factors were analyzed for diagnostic accuracy, sensitivity, core tissue, and blood contamination. RESULTS: A total of 629 passes were performed in 244 cases at 14 centers between 2018 and 2019. The median tumor size was 29 mm, and the puncture was transduodenal in 43%. The median pass number was 2. Diagnostic accuracy per session, at a first pass, and per pass were 93%, 90%, and 88%. In 198 cases with pancreatic cancer, diagnostic sensitivity per session, at a first pass, and per pass were 94%, 89%, and 89%. The rates of core tissue score of 4 and blood contamination score of 3 were 50% and 47%. The adverse event rate was 1.6%. In the multivariate analysis, tumor size ≤20 mm (odds ratio [OR] of 0.46, P = 0.03), transduodenal puncture (OR of 0.53, P = 0.04), and suction (OR of 0.16, P = 0.01) were associated with lower diagnostic accuracy. CONCLUSIONS: The EUS-FNB using the 22-gauge Franseen needle for pancreatic solid lesions showed high per pass and overall diagnostic accuracy.

Predicting Therapeutic Efficacy of Transarterial Chemoembolization with Drug-Eluting Beads for Hepatocellular Carcinoma Using Contrast-Enhanced Ultrasound.

The aim of this study was to assess the usefulness of contrast-enhanced ultrasound (CEUS) for predicting the therapeutic efficacy of transarterial chemoembolization with drug-eluting beads (DEB-TACE) for hepatocellular carcinoma (HCC). Thirty-two patients with HCC who underwent DEB-TACE were enrolled in this study. Enhancement patterns of vascular phase images on CEUS were compared before and within 3 days after DEB-TACE, and the patterns after DEB-TACE were classified as follows: Pattern A, no enhancement; Pattern B, peripheral ring enhancement; Pattern C, partial enhancement within or peripheral to tumors, and Pattern D, reduced or unchanged enhancement in the whole tumor. Enhancement patterns in all lesions and contrast-enhanced computed tomography (CECT) findings after DEB-TACE were compared statistically. The treatment response of DEB-TACE was evaluated using the Modified Response Evaluation Criteria in Solid Tumors (mRECIST) by CECT. The enhancement patterns on CEUS performed within 3 days after DEB-TACE were defined as Pattern A in 17 cases, B in 7, C in 13, and D in 2. The complete response rates at one month after treatment were 94.1% (16/17 lesions) for Pattern A, 85.7% (6/7) for B, 15.4% (2/13) for C, and 50% (1/2) for D. The response rates were significantly higher for lesions with Pattern A compared to those with Pattern C at one month (p = 0.009) and 12 months (p < 0.001) after treatment, and significantly higher for lesions with Pattern B compared to those with Pattern C at 12 months after treatment (p = 0.031). Comparisons between other patterns showed no significant differences. CEUS immediately after DEB-TACE may allow early assessment of therapeutic efficacy, with findings of no enhancement or peripheral ring enhancement suggesting a positive outcome.

Unilateral versus Bilateral Endoscopic Nasobiliary Drainage and Subsequent Metal Stent Placement for Unresectable Malignant Hilar Obstruction: A Multicenter Randomized Controlled Trial.

(1) Background: Endoscopic management of hilar biliary obstruction is still challenging. Compared with unilateral drainage, bilateral drainage could preserve larger functional liver volume and potentially improve clinical outcomes. To evaluate the effectiveness of bilateral drainage, we conducted this multicenter randomized controlled study. (2) Methods: Patients with unresectable malignant hilar biliary obstruction were assigned to unilateral or bilateral group. At first, patients underwent endoscopic nasobiliary drainage (ENBD), and subsequently underwent self-expandable metallic stent (SEMS) deployment. Primary outcomes were the functional success rate of ENBD and time to recurrent biliary obstruction (TRBO) after SEMS deployment. (3) Results: During the study period, 38 and 39 patients were enrolled in the unilateral and bilateral groups. The functional success rate was similar in the uni- and bi-ENBD group (57% vs. 56%; p = 0.99), but the rate of additional drainage was higher in uni-ENBD group. Although TRBO and overall survival time after SEMS deployment were not different between the groups (p = 0.11 and 0.78, respectively), the incidence of early adverse events tended to be higher in the bi-SEMS group (5.3% vs. 28%; p = 0.11). (4) Conclusions: Our study failed to demonstrate the superiority of bilateral over unilateral biliary drainage in terms of functional success rate and TRBO.

Multicentre prospective observational study protocol for radiation exposure from gastrointestinal fluoroscopic procedures (REX-GI study).

INTRODUCTION: Recently, the use of various endoscopic procedures under X-ray fluoroscopic guidance, such as endoscopic retrograde cholangiopancreatography (ERCP), interventional endoscopic ultrasonography (EUS), enteral endoscopy and stenting, has been rapidly increasing because of the minimally invasive nature of these procedures compared with that of surgical intervention. With the spread of CT and fluoroscopic interventions, including endoscopic procedures under X-ray guidance, high levels of radiation exposure (RE) from medical imaging have led to major concerns throughout society. However, information about RE related to these image-guided procedures in gastrointestinal endoscopy is scarce, and the RE reference levels have not been established. The aim of this study is to prospectively collect the actual RE dose and to help establish diagnostic reference levels (DRLs) in the field of gastroenterology in Japan. METHODS AND ANALYSIS: This is a multicentre, prospective observational study that is being conducted to collect the actual RE from treatments and diagnostic procedures, including ERCP, interventional EUS, balloon-assisted enteroscopy, enteral metallic stent placement and enteral tube placement. We will measure the total fluoroscopy time (min), the total dose-area product (Gycm2) and air-kerma (mGy) of those procedures. Because we are collecting the actual RE data and identifying the influential factors through a prospective, nationwide design, this study will provide guidance regarding the DRLs of ERCP, interventional EUS, balloon-assisted enteroscopy, enteral metallic stent placement and enteral tube placement. ETHICS AND DISSEMINATION: Approval was obtained from the Institutional Review Board of Toyonaka Municipal Hospital (25 April 2019). The need for informed consent will be waived via the opt-out method of each hospital website. TRIAL REGISTRATION NUMBER: The UMIN Clinical Trials Registry, UMIN000036525.

Factors related to difficult self-expandable metallic stent placement for malignant colonic obstruction: A post-hoc analysis of a multicenter study across Japan.

BACKGROUND AND AIM: Colorectal cancer patients often present with large bowel obstruction. Elective placement of a self-expandable metallic stent (SEMS) can relieve obstruction, but can be challenging. Previous studies have compared cases by outcomes only, but the present study investigated successful cases only to identify factors related to prolonged and difficult SEMS placement in patients with malignant colonic obstruction. METHODS: A post-hoc analysis of a multicenter clinical trial conducted between March 2012 and October 2013 at 46 facilities across Japan (UMIN000007953) was carried out; 511 patients who required SEMS placement for acute colorectal obstruction or symptomatic stricture secondary to malignant neoplasm were enrolled. Technical success rates and procedure times were recorded. Clinical and interventional parameters were investigated for their potential effect on procedure time by univariate and multivariate analyses. RESULTS: Technical success rate of SEMS placement was 98%. Median procedure time was 30 (range, 4-170) min. In 27% of patients, procedure time exceeded 45 min, indicating technically difficult placement. Multivariate analyses showed significant associations between technically difficult placement and a ColoRectal Obstruction Scoring System (CROSS) score of 0 before SEMS placement (odds ratio [OR], 1.6; P < 0.05), tumor site in the right colon (OR, 2.5; P < 0.0001), stricture length ≥5 cm (OR, 2.2; P < 0.001), peritoneal carcinomatosis (OR, 1.7; P < 0.05), and multiple SEMS placement (OR, 8.0; P < 0.01). CONCLUSION: Clinicians must anticipate technical challenges in cases with peritoneal carcinomatosis, a CROSS score of 0, or expansive strictures; such cases require experienced clinicians to carry out SEMS placement.

Diagnostic outcomes of esophageal cancer by artificial intelligence using convolutional neural networks.

BACKGROUND AND AIMS: The prognosis of esophageal cancer is relatively poor. Patients are usually diagnosed at an advanced stage when it is often too late for effective treatment. Recently, artificial intelligence (AI) using deep learning has made remarkable progress in medicine. However, there are no reports on its application for diagnosing esophageal cancer. Here, we demonstrate the diagnostic ability of AI to detect esophageal cancer including squamous cell carcinoma and adenocarcinoma. METHODS: We retrospectively collected 8428 training images of esophageal cancer from 384 patients at the Cancer Institute Hospital, Japan. Using these, we developed deep learning through convolutional neural networks (CNNs). We also prepared 1118 test images for 47 patients with 49 esophageal cancers and 50 patients without esophageal cancer to evaluate the diagnostic accuracy. RESULTS: The CNN took 27 seconds to analyze 1118 test images and correctly detected esophageal cancer cases with a sensitivity of 98%. CNN could detect all 7 small cancer lesions less than 10 mm in size. Although the positive predictive value for each image was 40%, misdiagnosing shadows and normal structures led to a negative predictive value of 95%. The CNN could distinguish superficial esophageal cancer from advanced cancer with an accuracy of 98%. CONCLUSIONS: The constructed CNN system for detecting esophageal cancer can analyze stored endoscopic images in a short time with high sensitivity. However, more training would lead to higher diagnostic accuracy. This system can facilitate early detection in practice, leading to a better prognosis in the near future.