Metastatic diseases were found in 20-25% of patients with initial diagnosis of colorectal cancer and developed in up to 50% of patients. Owing to limited post-treatment response of 5-fluorouracil (5-FU) combined with leucovorin (LV) obtained in mCRC (metastatic colorectal cancer) patients, other therapeutic agents with different mechanisms were considered, such as irinotecan, a potent inhibitor of topoisomerase I, which is involved in the unwinding of DNA during replication. Bevacizumab is a humanized monoclonal antibody that inhibits tumor angiogenesis by blocking vascular endothelial growth factor (VEGF) and was the first antiangiogenic agent approved for the treatment of cancer.