Introduction: Gastric atrophy and intestinal metaplasia are the principal precursors for gastric cancer and, therefore, are considered gastric premalignant conditions. Although current guidelines recommend surveillance of individuals with these conditions, the best method for its identification and staging (histological vs endoscopy) and the best time schedule for follow-up are still controversial.

Aims: To describe for the first-time patients with premalignant conditions both clinically (familial history), histologically (OLGA/OLGIM; complete/incomplete metaplasia) and endoscopically (EGGIM) using validated scales and to describe evolution of these parameters through time. To estimate prospectively the gastric cancer risk according to EGGIM stages. To define the best endoscopic surveillance follow-up for the several stages considering clinical, histological and endoscopic factors.

Methods: Multicenter study involving different gastroenterology departments from several countries. Consecutive patients older than 45 years scheduled for upper endoscopy in each of these centers will be evaluated by High-Resolution- endoscopy with virtual chromoendoscopy and EGGIM will be calculated. Guided biopsies (if areas suspicious of IM) and/or random biopsies (if no areas suspicious of IM) in antrum and corpus will be made and OLGA/OLGIM stages calculated. Patients will be evaluated in clinical consultation and database will be fulfilled. All patients will be eradicated for Helicobacter pylori infection if positive. At that occasion, all the patients with EGGIM\>5 and/or OLGA III/IV and/or OLGIM III/IV will be randomized for yearly (12 to 16 months) or every three years (32-40 months) endoscopic follow-up during a period of 6 years (SUPREME I). Endoscopic observational follow-up will be scheduled for patients with EGGIM 1-4 and OLGIM I/II at 3 and 6 years (SUPREME II). For individuals with no evidence of IM (EGGIM 0 and OLGIM 0, OLGA 0-II) a follow-up endoscopy 6 years after will be proposed (SUPREME III).