Gastric outlet obstruction in malignant disease appears when the tumor affects the gastroduodenal area, precluding the passage of food into the small bowel. This condition severely affects the quality of life. In patients with unresectable tumors, there are various available treatments:a surgical bypass connecting the stomach to the small bowel, placing a stent through the tumor to widen the passage and creating a gastrointestinal bypass with a lumen apposing metal stent. These stents are deployed with an echoendoscope, which allows to identify a small bowel loop and to deploy the stent, connecting the small bowel and the stomach. This is called a EUS-guided gastroenterostomy (EUS-GE).

EUS-GE is a rather novel procedure. Various techniques to create EUS-GE have been proposed. In this study, the investigators will retrieve data from the procedure and during the thirty following days from consecutive patients undergoing an EUS-GE. The objectives of the study are:

• To perform a detailed step by step description of the nasobiliary drain assisted EUS-GE
• To describe the adverse events encountered
• To describe the proportion of clinical and technical success
• To assess its impact on the patients' quality of life.
• To assess the evolution of the oral intake during the first month after the procedure

DESIGN

Prospective multicenter case series

AIMS

Primary aim To describe the proportions of technical and clinical success. To describe different variants in the nasobiliary drain assissted EUS-GE technique, offering a detailed step by step description of the procedure performance by different endoscopists

Secondary aims:

To describe the adverse encountered, their severity according to ASGE standards and their management.

To describe the time elapsed between the procedure and the initial oral intake.

To describe the evolution of the oral intake during the first month after the procedure To assess the impact of the operators experience on procedure times, adverse events and technical issues.

To assess the impact of the procedure on the quality of life of the participating patients.

STUDY POPULATION

All consecutive patients over 18 years of age receiving a nasobiliary drain assisted EUS-GE for unresectable malignant GOO are eligible to participate in this study. Patients with a previous gastroduodenal surgery, a previous endoscopic or surgical treatment for GOO, a simultaneous malignant biliary obstruction requiring endoscopic treatment, a distal bowel obstruction, ascites grade 2 or superior, uncorrectable coagulation disorders (INR>1,5) or severe thrombocytopenia (<50000 platelets/mm3). or unable to understand the questionnaires will be excluded.

INTERVENTION

At inclusion

Informed consent will be obtained. A clinical interview and a physical examination will be performed. TheEuropean Organization for Research and Treatment of Cancer QoL Questionnaire Core 30 (EORTC-QLQ-C30), which includes 30 items covering a global health status scale, five functional scales and ten symptom scales will be assessed in a telephone interview.

Endoscopic procedure

All procedures will be performed under sedation. An assistant endoscopist or research nurse will retrieve all data regarding the procedure. Firstly, un upper digestive endoscopy is performed with a conventional gastroscope. A guidewire is passed through the malignant lesion causing the gastric outlet obstruction. Once the guidewire is located in the distal duodenum/proximal jejunum, a nasobiliary drain (Nasal Biliary Drainage Sets, Cook medical, Indiana) is advanced over the guidewire until its distal end is placed in the distal duodenum/jejunum. At this point the gastroscope is substituted by a therapeutic echoendoscope. With the echoendoscope in place, the target bowel loop is filled with saline combined with methilene blue and radiopaque contrast. The echoendoscope is used to identify the target bowel loop. AFter identifying the target, a lumen apposing metal stent (Axios, Boston Scientific, Massachusetts) is deployed across the gastric and bowel using its electrocautery enhanced deployment device.

Post procedure: Oral liquid intake can be restarted 4h after the procedure in patients presenting no signs or symptoms suggesting any adverse event. Pacients with an adequate tolerance might be discharged.

Follow-up

Clinical telephone interviews by an experienced research nurse will be held via telephone calls 1 day, 7 days and 30 days after the procedure. Oral intake and adverse events will be assessed every visit. Thirty days after the procedure a second evaluation of the EORTC-QLQ-C30 will be performed.

STATISTICAL ANALYSIS

Categorical variables were reported as percentages. Normally distributed continuous variables were reported as the mean with the standard deviation values. Non-normally distributed continuous variables were reported as the median and interquartile range. The EORTC QLQ-C30 descriptive analysis was performed with a specifically programmed Stata command (10). Variables regarding the procedure step by step analysis will only undergo a descriptive analysis. Differences between the different outcomes of the EORTC-QLQ-C30 will be assessed using linear mixed models with fixed effects for baseline values, and interaction with oncological treatment. The statistical analysis will be performed using the Stata package (StataCorp. 2013, College Station, Texas).

Inclusion Criteria:

• Patients over 18 years of age
• unresectable malignant gastric outlet obstruction
• Undergoing placement of nasobiliary drain assisted EUS-GE

Exclusion Criteria:

• Previous gastroduodenal surgery
• Previous endoscopic or surgical treatment for gastric outlet obstruction
• Simultaneous biliary obstruction (malignant or benign) requiring endoscopic treatment
• Simultaneous upper digestive tract disease requiring endoscopic treatment in the same procedure
• Unable to understand the questionnaires
• Distal bowel obstruction
• Ascites grade 2 or superior
• Uncorrectable coagulation disorders (INR>1,5) or severe thrombocytopenia (<50000 platelets/mm3).
• Active, symptomatic SARS-CoV-2 infection

All consecutive patients over 18 years of age submitted to any of the participanting center's endoscopy units to receive a nasobiliary drain assisted EUS-GE for unresectable malignant GOO are eligible to participate in this study.

Patients with a previous gastroduodenal surgery, a previous endoscopic or surgical treatment for GOO, a simultaneous malignant biliary obstruction or unable to understand the questionnaires will be excluded.

After the study is completed a csv including all study data can be submitted to a repository or made available to applying investigators.