COLOSPOT Study : Assessment by EPISPOT of Circulating Tumor Cells in Patients With Metastatic Colorectal Cancer

For each patient, we will perform a counting of CTC before chemotherapy and then at different time points after chemotherapy, using both technologies: EPISPOT and CellSearch®.For the EPISPOT, we will need 15 mL of peripheral blood on EDTA tubes. For each patient, five blood samples will be done: D0, D14, D28, D42 and D56. These different time points will help us to determine when the best moment is for the evaluation of the CTC with this technology.For the CellSearch®, we will need 10 mL of peripheral blood on a specific CellSave tube. Only two samples will be perform: D0 and D28 because Cohen et al. (2008) reported that the best appropriated moment to appreciate the CTC progression is between 3 and 5 weeks after the initiation of the treatment.