Antiangiogenic therapy in colorectal cancer: where are we 5 years later?

The past 5 years mark a watershed period in the treatment of patients with colorectal cancer (CRC). During this time, results from several clinical trials proved that targeting tumor-mediated angiogenesis improves overall survival for patients with metastatic CRC (mCRC) when used in combination with first-line and second-line chemotherapy regimens, data that do not simply serve as "proof of principle" for antiangiogenic therapy but that will drive much of the research agenda in CRC for the coming years. Despite the demonstrated gains in survival when antiangiogenic therapy is used for patients with metastatic disease, however, results from the first trial to test the addition of bevacizumab to adjuvant chemotherapy have been disappointing. The expense of agents in the targeted therapy category has been the cause of much discussion on their appropriate use and puts particular emphasis on the need for suitable markers that will allow for the appropriate selection of patients. Although antiangiogenic therapy has demonstrated clear benefit in the treatment of patients with mCRC, limitations in efficacy, duration of therapy, role of maintenance therapy, potential toxicities, and predictive markers for optimal patient selection are subjects of ongoing research. Herein, we present a review of the recent advances in antiangiogenic therapy in CRC and provide insights into several promising upcoming studies.