All patients qualified between June 2001 and December 2005 to total and distal subtotal gastrectomy or pancreaticoduodenectomy were screened for eligibility to participate in the study. Additional eligibility criteria included: age between 18 and 80 years, Karnofsky performance status score of 80 or more, and adequate organ function measured by routine blood tests. Patients requiring preoperative nutritional support, as well as those with disseminated tumors, serious comorbidities (American Society of Anesthesiologists risk class of 4 or 5), and renal or liver failure were excluded. The study was designed to test the hypothesis that immunonutrition and enteral nutrition would reduce the incidence of infectious complications following upper gastrointestinal surgery. Therefore, patients were randomly assigned in a 2×2 factorial design to four groups receiving immunostimulating versus normal diets, and enteral versus intravenous nutritional support. The secondary objective of the study was to evaluate the effect of nutritional intervention on overall morbidity and mortality rates, and the length of hospital stay.
After completing tumor resection, patients who met the eligibility criteria were intraoperatively assigned to either of the treatment groups using sealed envelopes containing computer-generated allocation numbers. The following groups were generated: standard enteral nutrition (SEN), immunostimulating enteral nutrition (IMEN), standard parenteral nutrition (SPN), and immunostimulating parenteral nutrition (IMPN). The study was carried out following the international ethical recommendations stated in the Declaration of Helsinki.
