RecruitingDietary supplementEvaluation of the Administration of Artificial Nutrition by Feeding Jejunostomy During Neoadjuvant Treatment on Postoperative Morbidity in the Context of Esophageal or Stomach CancerMalnutrition is common at the time of diagnosis of esogastric cancers. However, there are no recommendations regarding preoperative nutritional support (type and duration) or on the impact of refeeding on postoperative morbidity and mortality.