Chemotherapy With or Without Radiation or Surgery in Treating Participants With Oligometastatic Esophageal or Gastric Cancer

Inclusion Criteria: * The patient has a pathologic diagnosis of tumor biopsy or FNA of esophageal or gastric cancer of adenocarcinoma histology * The patient is staged with EGD and PET/CT scan. * The patient has three or less observable metastatic lesions. Patients may have three or less radiographically visible metastatic lesions at diagnosis or if have regressed to three or less metastatic lesions after induction chemotherapy at time of randomization. The patient must have pathologic confirmation and or radiologically visible disease. For esophageal tumors, the maximal dimension of the primary tumor may not provide reproducible measurements for RECIST and may not be visible on CT or PET/CT at diagnosis or after induction chemotherapy. Accordingly, patients are eligible regardless of the imaging measurements of the primary tumor. Additionally, in patients with non-measurable metastases, patients are eligible if there is pathology confirming metastases from a distant site. However, biopsy of a metastatic site is not required if there are visible metastases on imaging (such as ultrasound, diagnostic CT , EUS, PET/CT). * The patient has three or less observable metastatic lesions by diagnostic scans (CT scan, PET/CT, eEndoscopic ultrasound, MRI, or bone scan). Metastatic lesions include distant M1 lymph node group; which will be counted as one site (M1 metastatic lymph nodes to include cervical, mediastinal, gastric, retroperitoneal lymph nodes will be counted as one lesion…