Timing of Minimally Invasive Local Treatment After First-Line Systemic Therapy in Oligometastatic Esophageal or Gastric Adenocarcinoma

Chemotherapy preferably CapOx (capecitabine + oxaliplatin) or FOLFOX (5-fluoruracil, leucovorin and oxaliplatin) will be combined with immunotherapy (preferably nivolumab or pembrolizumab) and/or targeted therapy (for example trastuzumab in the case of HER2 overexpression or zolbetuximab in the case of Claudin 18.2 overexpression). These regiments are the standard-of-care (SOC) combination therapies used in this study. Acceptable chemotherapy regimens predominantly for Asian centers include SOX (S-1 and Oxaliplatin).

Biomarker selected patients will receive trastuzumab, zolbetuximab or any other targeted agent according to standard of care.

Biomarker selected patients will recieve checkpoint inhibitors according to standard care

If the primary tumor is present, this tumor will be surgically removed. Metastases may also be removed by surgery.

Metastases may be irradiated