Evaluate Esophageal Reinforcement With ACell MatriStem Surgical Matrix: A Degradable Biologic Scaffold Material

Inclusion Criteria: * Patient 18 years of age or older * Pathologically confirmed Gastric, Gastroesophageal Junction (GEJ) or Esophageal, adenocarcinoma at either MSKCC or a participating site (biopsy may be performed at other institutions but slides must be confirmed at MSKCC or a participating site, as is routine care at our institution) * Patient undergoing any resection requiring an anastomosis to the esophagus for curative intent. Including but not limited to esophagectomy or total gastrectomy. * Subject is willing to provide written informed consent * Subject is willing and able to comply with the follow-up regimen Exclusion Criteria: * Pregnant or lactating women * Intraoperative evidence of metastatic or locally-unresectable disease * Patients with known sensitivity or allergy to porcine materials. * Patients undergoing any resection requiring an anastomosis to the esophagus for palliative intent.