H. pylori-associated Gastric MALT Lymphoma

A 58-year-old man with an 8-year history of untreated *Helicobacter pylori* infection presents with 6 months of epigastric discomfort, postprandial fullness, and microcytic anemia (Hb 11.2 g/dL). Upper endoscopy reveals striking abnormalities in the gastric antrum and lesser curvature. The structure marked **A** — the thickened, nodular, cobblestone-like mucosa with loss of normal rugal pattern — is biopsied and shows a dense lymphoid infiltrate with centrocyte-like B cells and lymphoepithelial lesions. Immunohistochemistry confirms CD20+, CD5−, CD10−, CD23− B-cell lymphoma. Cytogenetic studies show no t(11;18) translocation. Endoscopic ultrasound confirms stage I disease. What is the most appropriate FIRST-LINE management for this patient?