Contemporary management of advanced gastric and gastroesophageal adenocarcinomas

Gastric and gastroesophageal adenocarcinomas (GEACs) continue to carry a poor prognosis in most patients. New and exciting therapies have entered the treatment landscape in recent years. Prior to these recent approvals, treatment advances had been limited. Important treatment decision biomarkers for metastatic GEAC are microsatellite instability-high/deficient mismatch repair, human epidermal growth factor receptor-2, programmed-death ligand 1, and claudin 18.2 expression among others (such as Epstein Barr Virus (EBV) and agnostic biomarkers). Results of these biomarkers drive therapy decisions. Second-line treatment in most cases is less biomarker driven and needs further progress. Studies of molecular subsets in GEAC has led to the understanding that these are heterogenous diseases that need to be treated differently. Other biomarkers with targeted therapies are being studied including fibroblast growth factor receptor, trophoblast cell surface antigen-2, and epidermal growth factor receptor. Additionally, epidemiological distinctions are starting to drive therapy such as in EBV in GAC.