This study focuses on immunonutrition used for the prehabilitation of patients with colorectal cancer before surgery. The main objective is to investigate the impact of dietary supplements. Specifically, it compares oral nutritional supplements with immunonutrition and standard oral nutritional supplements. The condition addressed by the study is colorectal cancer. The study was sponsored by the Fundacion para la Investigacion Biomedica del Hospital Universitario Ramon y Cajal. This research work has been completed.