Submucosal Tumor Removal by Endoscopic Excision Therapy

Study Overview
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Brief Summary
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Smaller submucosal tumors (SMT) in the stomach are usually seen as an incidental finding during a gastroscopy, although current diagnostics usually do not clearly indicate what type of tumor it is. In summary, there is no good evidence for dealing with SMT. In this study, an endoscopic full-thickness resection, primarily with the FTRD device, is to be offered to all patients with gastric SMT without a confirmed histology seen in a certain period of time . Patients who do not want to take advantage of this are included in a systematic follow-up program. The investigators hope to learn about the rate of so-called GIST tumors and other histologies, as well as the rate of change in the follow-up group. Also, study contents will be accuracy of endosonographic imaging and puncture in comparison with resection histology, technical feasibility and histological completeness of the FTRD- based endoscopic (full-wall) resection option, complications of such a resection (secondary bleeding and dehiscences), and patient preferences with standardized information.

Detailed Description
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Smaller submucous tumors in the stomach are usually seen as a random finding in gastroscopies and present a diagnostic dilemma to the doctor and patient: type specification is usually unclear whether it is an absolutely benign (without degeneration potential) or a malignant or prone tumor (usually gastrointestinal stromal tumor, GIST). However, this is crucial for further management. In endosonographic imaging there are only approximate values in the differential diagnosis between GIST and non-GIST, the endoscopic biopsy is too superficial, and the hit rate of endosonographic pin puncture is limited, and in most studies is less than 70% Therefore, one can only make assumptions and create a risk profile from imaging and tumor size (limit size 3 cm, partly also 2 cm). Both follow-up recommendations (rather no GIST) and laparoscopic surgical removal (proven or probable/possible GIST) are not rarely without clear preference, especially for smaller tumors. For these indications, a simple endoscopic removal option comparable to the polypectomy in the colon (where no histological type diagnosis is made before) does not exist. Previous studies are usually subject to bias in several directions: The frequency of GIST tumors among submucous tumors/lesions (SMT) in the stomach is unclear. Gastroenterological series always contain smaller GIST tumors, but are reported almost exclusively from clinics. The rate of these tumors in the overall collective of patients seen in the field of (mostly established) gastroenterologists is thus completely unclear. Surgical or oncological series have usually included more aggressive tumors consisting mainly or exclusively of GIST tumors, therefore do not allow epidemiological conclusions. If no surgery is performed (and thus a definitive histology is forced), only information from follow-up examinations remains. Previous follow-up studies show the dilemma of insufficient differential diagnosis of lesions by endosonography and (endosonographic or other) biopsy, which usually have insufficient accuracy. In addition, the follow-up time in the studies hardly extends beyond 2 years. The gastroenterological gut instinct that these small lesions are not dangerous may be true, but is not proven.

Official Title
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Prospective One-armed Observational Study of Full-thickness Resection of Small Hypoechoic Submucosal Gastric Tumors (≤2 cm)

Conditions
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Submucosal Tumor of Stomach

Intervention / Treatment
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* Other: removal of submucosal gastric tumor preferably by Full Thickness Resection Device (FTRD)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients with endoscopically diagnosed and endosonographically confirmed submucosal tumors of 0.5 to 2 cm in the stomach without definitive histology / cytology Initial diagnosis less than 2 years ago No contraindication to endoscopic resection Patient's informed consent Exclusion Criteria: Tumor size > 2 cm Tumors with proven / suspected malignancy for which oncologically no endoscopic resection should be performed, i.e. for which oncological or surgical therapy is planned SMT known > 2 Years Patients with severe general illnesses (limited operability) or malignancies Clotting disorders Pregnancy

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 80 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Diagnostic
Intervention Model: Single Group Assignment
Interventional Model Description: Submucosal gastric Tumors up to 2 centimeters of size
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: Removal of submucosal gastric tumor preferably by Full Thickness Resection Device (FTRD)<br>FTRD (Ovesco company) in tumors up to 10 mm and predominantly intraluminal growth directly by sucking into the cap, at 10-20 mm and/or intramural/extramural growth by prior circumcision and lateral preparation, so that the lesions can be better pulled into the cap. The procedure depends on the endosonographic extent of the findings. The lesions are pulled into the cap with grippers and other instruments and, if necessary, with a snare and then resected with FTRD | Other: removal of submucosal gastric tumor preferably by Full Thickness Resection Device (FTRD)<br>* FTRD (Ovesco company) in tumors up to 10 mm and predominantly intraluminal growth directly by sucking into the cap, at 10-20 mm and/or intramural/extramural growth by prior circumcision and lateral preparation, so that the lesions can be better pulled into the cap. The procedure depends on the endosonographic extent of the findings. The lesions are pulled into the cap with grippers and other instruments and, if necessary, with a snare and then resected with FTRD<br>* Other names: Endoscopic submucosal dissection (ESD);|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Rate of GIST tumors | Rate of GIST tumors in a preferably unselected patient cohort of small submucous gastric tumors in which histology is not known | through study completion, approximately 2 years | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Technical success | Technical success rate (R0/R1 resection) of the chosen resection technique | through study completion, approximately 2 years | 
| Complication rate | Complication rate of the chosen resection technique | through study completion, approximately 2 years | 
| influencing factors on the GIST rate: tumor size | Influence of tumor size on the GIST rate | through study completion, approximately 2 years | 
| Influencing factors on the GIST rate: position of tumor | Influence of tumor position in the stomach | through study completion, approximately 2 years | 
| Influencing factors on the GIST rate: endoscopic ultrasound image | endoscopic ultrasound image with pattern and position in the wall | through study completion, approximately 2 years | 
| Influencing factors on the GIST rate: patient's age | Age of patients | through study completion, approximately 2 years | 
| Influencing factors on the GIST rate: patient's gender | gender of patients | through study completion, approximately 2 years | 
| Influencing factors on the GIST rate: anamnesis | anamnesis including initial diagnosis | through study completion, approximately 2 years | 
| Patient's preferred approach | Patient preferences for removal (consent rate for the study) versus follow-up | through study completion, approximately 2 years | 
| data for cost-benefit calculation | Establishment of a date base for a cost-benefit calculation comparing follow-up vs. removal | through study completion, approximately 2 years | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Submucosal Tumor of Stomach, GIST, FTRD