Metronomic chemotherapy in metastatic colorectal cancer

Overall survival and quality of life of patients with metastatic colorectal cancer (mCRC) have improved due to the development of standard systemic treatment. However, many patients are still suffering from the eventual progression of cancer, treatment-related toxicities, and the economic burden of new drugs. Salvage or maintenance therapy, which consistently controls or stabilizes tumor progression without debilitating quality of life, is required. Recently, metronomic capecitabine maintenance therapy after disease control using conventional chemotherapy with maximal tolerated doses has demonstrated beneficial results in a phase III trial. Metronomic chemotherapy has been known to control tumors through antiangiogenesis and immunomodulation as well as a direct effect on tumor-initiating cells. It has the characteristics of being minimally toxic, inexpensive, and durable for maintaining disease stabilization. Therefore, patients with mCRC, who tend to be elderly and frail and have been previously treated, might be suitable for metronomic therapeutic strategies. Furthermore, antiangiogenic therapy has been an important component in treating mCRC, but the schedules and doses of metronomic chemotherapy have not yet been established. Here we review translational and clinical research on metronomic chemotherapy in colorectal cancer (CRC).