RecruitingPhase 2Drug trialCombined Systemic and Intraperitoneal Chemotherapy for Synchronous Gastric and/or Gastroesophageal Peritoneal CarcinomatosisThis trial will administer laparoscopic hyperthermic intraperitoneal chemotherapy (HIPEC) to patients with peritoneal carcinomatosis from gastric cancer (GPC) who are receiving standard of care systemic chemotherapy.