Up to 30-40% of patients operated from colorectal cancer display tumor recurrence. Predictive biomarkers are needed to identify those patients with higher risk of recurrence. Our main objective is to determine a metabolite profile in blood plasma from patients operated from colorectal cancer that can be associated with the oncologic outcome and be validated as prognostic biomarkers in future studies. A secondary objective is to study the glycolytic metabolism of colon cancer cell lines treated with plasma samples from the same patients. In particular, to validate the increased utilization of lactate by tumor cells as a metabolic substrate using postoperative human samples, as it was previously observed by us in vitro using an inflammatory environment in conditions of hypoxia and lack of glucose. Patients with colorectal cancer that have undergone surgical resection will be included. Plasma samples will be obtained before surgery and the 4th day and the 3rd, 6th, 12th, and 18th months after surgery. Metabolic profiles in plasma samples will be determined using a kit that allows the quantification of 180 metabolites by mass spectrometry. Cellular assays will be performed on the SW620 and HT-29 colon cancer cell lines. Cells will be treated with plasma samples and the concentration of lactate and other metabolites will be analyzed in the medium supernatants. A clinical follow up will be maintained for at least 2 years to identify tumor recurrences.