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.