problems encountered during the patient recruitment phase which led to the pre-established recruitment objectives not being met.

Compared to upper gastrointestinal (GI) malignancies, CRC patients generally present with satisfactory nutritional status at surgery and malnutrition is typically present in advanced stages of CRC. Therefore, in the latter surgery may not be offered with curative intent. Based on the current evidence, the role of OIN appears to be consolidated for malnourished patients undergoing surgery for gastrointestinal cancer. Regarding not malnourished patients, there is still no clear correlation between OIN and decrease in post-operative complications. Furthermore, whether OIN increases immune response within the tumour microenvironment is based on studies with poor number of patients.

Randomized, controlled, open-label, single-centre study in patients candidate for elective curative surgery for colon-rectal cancer.

The study intervention consists of the oral nutritional supplementation enriched with immune-nutrients delivered before and after surgery in addition to standard dietary advice according to E.R.A.S. protocol.

All patients will follow low-fiber diet according to ERAS protocol during the study period. Patients assigned to the experimental arm will assume also Impact Oral®, an oral nutritional supplement with immune-nutrients (hyper-proteic formula), manufactured and commercialized by Nestlé Health Science S.p.a. It is a liquid drink packaged in a brick of 237 ml. Patients will assume Impact Oral® for 5 days before surgery and 5 day after surgery.

Inclusion Criteria:

• Patients aged ≥ 18 years or older;
• histologically confirmed adenocarcinoma of colon or rectum;
• Eligible for elective curative surgery with indication of colon and/or rectal resection in laparoscopy with mini-invasive technique;
• eligible for ERAS protocol;
• Written informed consent to the study participation according to the Local Ethic Committee requirements before any study procedure;

Exclusion Criteria:

• colon or rectal resection for benign disease;
• TNM Stage ≥4;
• neoadjuvant radio and/or chemotherapy
• ASA score > 3;
• contraindications to oral nutrition (e.g. dysphagia, pyloric stenosis) or hypersensitivity to any ingredient of study product;
• albuminemia < 3.0 g/l;
• weight loss > 10% in the last 3-6 months;
• BMI < 18.5 kg/m2;
• pregnant or breastfeeding;
• Not self-sufficient or with poor family compliance;
• Congenital or acquired immunodeficiency;
• Active uncontrolled pre-operative infections or other clinically relevant concomitant illness that preclude laparoscopic procedure;
• Bowel obstruction or parenteral nutrition or gastric tube;