A Randomized Study Comparing Autofluorescence Imaging(AFI) Followed by Narrow Band Imaging(NBI) With Videoendoscopy for the Detection of High Risk Lesions of Stomach

Study Overview
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Brief Summary
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Videoendoscopy is the standard tool for examination of gastrointestinal tract. However, precancerous lesions and early gastric cancer can be easily missed by routine videoendoscopy. Autofluorescence Imaging (AFI) and Narrow band imaging (NBI) are 2 new imaging systems used in endoscopy which are recently developed. AFI based on the presence of natural tissue fluorescence on the gastrointestinal tract. By computation of the difference in the reflecting images, the system can reveal early cancers that are not detectable by standard endoscopy. NBI is a high resolution imaging using lights with narrowed wavelength range, which able to enhance the fine structure of the mucosa. Recent studies suggested combined AFI and NBI can improve the detection of early esophageal and gastric cancers. The investigators are conducting a prospective randomized cross-over study to compare the accuracy between this combined AFI/NBI imaging with standard videoendoscopy in the detection of precancerous lesions and gastric cancer in a high risk population inSingapore. The investigators hypothesis is that this new combined imaging system improves the investigators detection of high risk lesions of stomach.

Detailed Description
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Gastric cancer remains one of the leading causes of cancer deaths worldwide. Early detection and diagnosis of gastric cancer improves the outcomes of treatment. However, most of gastric cancers detected in Singapore are late and advanced in stages. Videoendoscopy is the standard tool for examination of gastrointestinal tract. Despite the improvement of technology, early gastric cancers can be easily missed by routine examination, because there are few morphological changes. Therefore, a functional imaging modality, that can distinguish abnormal lesion from surrounding normal mucosa may complement the current videoendoscopy. Autofluorescence Imaging (AFI) based on the presence of natural tissue fluorescence on the gastrointestinal tract. When the mucosa was exposed by an excitation light, certain endogenous molecules (fluorophores) will emit fluorescence light of longer wavelength. The fluorescent light can be detected and spectrally analyzed. By computation of the difference in the reflecting images, the system can specify lesions, including malignancies from the adjacent mucosa, and can reveal early cancers that are not detectable by standard endoscopy. Narrow band imaging (NBI) is another novel optical imaging technique based on high resolution imaging, which aims at enhancing the fine structure of the mucosa. In NBI, the band widths of the red, blue, green components of the excitation light are narrowed to certain wavelength ranges, which allow better contrast of the superficial mucosa and the vascular structure. NBI has a maximum zoom capacity of 115 times. Abnormal lesions are detected by the presence of abnormal mucosal and vascular patterns. Recent studies suggested that these AFI and NBI systems can be complementary to each other. The resolution of AFI is low but it can be used as a 'red flag' technique to screen any suspicious lesions from the normal mucosa. On the other hand, NBI produces high resolution images which allows detailed examination and subsequent target biopsy of the suspicious lesions based on AFI. Preliminary reports from Japan and the Netherlands suggested this combined imaging method improves the detection of early esophageal and gastric cancers. Recently, a new endoscopy system has been developed that incorporates standard videoendoscopy system with both AFI and NBI modes. By pressing a switch, the endoscopy system can switch from normal white light to either a narrow band light or autofluorescence mode. This novel system reduces the convenience and discomfort for the patients to avoid repeated intubation. The purpose of this study is to prospectively evaluate this combined imaging modality for detection of high risk gastric lesions and early cancers by comparing it with standard videoendoscopy in a randomized fashion.

Official Title
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A Randomized Study Comparing Endoscopic Video-Autofluorescence Imaging Followed by Narrow Band Imaging With Standard Videoendoscopy for the Detection of High Risk Lesions of Stomach

Conditions
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Gastric Cancer

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age >=50 Ethnic Chinese Presenting symptom - dyspepsia Exclusion Criteria: Patients who are unable to give an informed consent. Patients with previous surgery of the stomach. Patients presented with active gastrointestinal bleeding.

Ages Eligible for Study
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Minimum Age: 50 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| SE then AFI/NBI<br>Patients will be randomised to be examined by standard videoendoscopy (SE) then combined AFI/NBI during the esophagogastroduodenoscopy (EGD) examination at same setting. | |
| AFI/NBI then SE<br>Patients will be randomised to be examined by combined AFI/NBI then standard videoendoscopy (SE) during the EGD examination at same setting. | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| To compare the detection rate of premalignant lesions(intestinal metaplasia, gastric atrophy, dysplasia) and early neoplasia of stomach between combined AFI/NBI endoscopy versus standard endoscopy | The purpose of this study is to prospectively evaluate this combined imaging modality for detection of high risk gastric lesions and early cancers by comparing it with standard videoendoscopy in a randomized fashion. | 6 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| To assess the diagnostic accuracy AFI and NBI imaging | We aim to identify a method to improve our diagnosis of high risk gastric lesions in our population. | 6 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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OGD, NBI, AFI, Videoendoscopy, Narrow Band Imaging, Autofluorescence Imaging