Validation of an Artificial Intelligence System Based on Raman Spectroscopy for Diagnosis of Gastric Premalignant Lesions and Early Gastric Cancer

Early detection and treatment of gastric premalignant lesion and early gastric cancer (EGC) have been proposed to improve outcomes of gastric cancer. Gastric dysplasia is a premalignant lesion and the penultimate stage in gastric carcinogenesis. On white light endoscopy (WLE), it is difficult to distinguish gastric dysplasia and EGC from benign pathology such as gastric intestinal metaplasia (GIM). Image enhanced endoscopy such as narrow-band imaging (NBI) is recommended to improve characterization of suspicious gastric lesions detected on WLE. Magnified-endoscopy with NBI (ME-NBI) have been shown to be superior to HD-WLE for diagnosis of GIM and EGC. Data on gastric dysplasia is less robust. Ultimately, biopsy is required to confirm diagnosis of gastric dysplasia/EGC. Gastric dysplasia can be classified into low-grade dysplasia (LGD) or high-grade dysplasia (HGD). Biopsy sampling may not be representative of the final histopathological grade of resected specimens and may under-stage dysplasia. Thus, endoscopic resection (ER) is recommended for gastric dysplasia and EGC on biopsy for diagnostic and therapeutic purpose. The current gap is to improve concordance of endoscopic and histologic findings of gastric dysplasia and early gastric cancer. Raman spectroscopy based artificial intelligence system (SPECTRA IMDx) was developed to provide an objective method to identify patients with gastric premalignant lesions and EGC. SPECTRA IMDx interrogate tissues at the cellular level and utilizes molecular information to provide actionable information to endoscopist during gastroscopy. Studies on diagnostic performance using Raman spectroscopy analysis devices have shown high sensitivity and specificity in detection of gastric cancer and precancerous lesions compared to WLE. However, these studies included few GIM, gastric dysplasia and gastric carcinoma. It is still unclear if Raman spectroscopy outperforms WLE in diagnosis of gastric HGD and EGC. In addition, the Raman spectroscopy algorithm is only able to characterize lesions into high risk (HGD/EGC) versus low risk (GIM/LGD/Gastritis/Normal). It is also uncertain if this technology is able to differentiate GIM and LGD. We plan to conduct a prospective trial to validate the diagnostic accuracy of SPECTRA for prediction of gastric HGD and EGC prior to gastric ER. Hypothesis: SPECTRA IMDx is able to differentiate higher risk lesions (HGD/EGC) from lower risk tissue/lesion (GIM/LGD/Gastritis/Normal)

Sex

All

Minimum age

21 Years

Maximum age

90 Years

Inclusion Criteria:

1. Known diagnosis of gastric dysplasia with visible lesion or early gastric cancer amenable to gastric ER (EMR or ESD); diagnosis made based on biopsy from gastroscopy performed within past six months
2. Age 21 to 90 years (selected age range based on demographic of patients managed at Changi General Hospital)
3. Ability to provide informed consent

Exclusion Criteria:

1. Subjects without mental capacity, refusal to provide consent, incarcerated status, pregnant subjects.
2. Subjects with advanced gastric cancer not amenable to endoscopic resection
3. Subjects with bleeding disorders, such as haemophilia, in whom ER and biopsies are contraindicated.
4. Subjects with active bleeding or coagulopathy precluding ER and biopsies.
5. Subject with severe co-morbid illness, such as end-stage renal failure (ESRF), congestive cardiac failure (CCF) and advanced liver cirrhosis.
6. Subjects on regular anti-platelet medications except aspirin or anti-coagulants must be able to undergo adequate washout period before gastroscopy. The subject's physician or study co-investigator will exercise their clinical judgement to ensure subject's safety.