To estimate the prevalence of histologically confirmed early gastric cancer (EGC) in an Indian multicentre cohort undergoing standardised high-quality upper gastrointestinal endoscopy. EGC is defined as gastric adenocarcinoma confined to the mucosa or submucosa (T1), irrespective of lymph node status, based on histopathology.

Gastric adenocarcinoma is a major global health problem and remains a leading cause of cancer-related mortality. Early detection significantly improves survival, with 5-year survival rates exceeding 80% in countries with established screening programmes, such as Japan and South Korea. In contrast, most patients in India are diagnosed at advanced stages, resulting in poor outcomes.

The Correa cascade describes a stepwise progression from chronic gastritis to atrophic gastritis, intestinal metaplasia (IM), dysplasia, and invasive adenocarcinoma. Helicobacter pylori infection is a major driver of this pathway. Identifying and characterising gastric precancerous lesions provides an opportunity for surveillance and early intervention. India lacks high-quality multicentre data on the prevalence and spectrum of gastric precancerous lesions and early gastric cancer. This study aims to systematically evaluate the gastric precancerous epithelial pathway using high-definition endoscopy and standardised histopathology across multiple centres in India.

The Observational Study Model is recorded as 'Other' because IND-PREP is a single-time-point, cross-sectional diagnostic study and does not conform to the listed epidemiologic models (cohort, case-control, case-only, case-crossover, ecologic, or family-based). A defined group of patients undergoing upper gastrointestinal endoscopy is assessed at one point for the detection and characterisation of early gastric cancer and precancerous conditions. There is no longitudinal follow-up and no exposure-defined comparison group, consistent with the Cross-Sectional time perspective.

1. Adults aged ≥40 years undergoing upper gastrointestinal endoscopy for dyspepsia or other clinical indications (nonalarming and alarming symptoms both).
2. Ability to provide written informed consent.

Exclusion Criteria:

1. Known gastric malignancy.
2. Prior gastric surgery (excluding H. pylori eradication).
3. Contraindications to endoscopy or biopsy.
4. Known hereditary gastric cancer syndromes.

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