Colorectal cancer is the most frequent tumor in our environment if both sexes are considered together. Every year almost 800 cases are diagnosed in the districts of Tarragona. A little more than half of colorectal cancers are cured with surgery, with or without the addition of complementary treatments with chemotherapy and/or radiation therapy. Those who are not cured is because at the time of diagnosis the disease has already spread or they spread after having been treated surgically with curative intent. The purpose of the EarlyCRC project is to determine whether metabolites (substances of low molecular weight) can be found in the urine and stool of patients with colorectal cancer or polyps that can be easily and cheaply differentiated (urine or stool analysis) between the patients affected by colorectal cancer or polyps, from healthy individuals. For the identification of these possible metabolites, the urine analysis will be performed using the usual techniques in metabolomics, which studies the existing metabolites in biological processes.