Perspectives in the treatment of colorectal cancer.

The availability of new chemotherapy agents in the last several years has had a significant impact on the treatment of colorectal cancer (CRC), but questions about how best to use these agents remain. In this article we review the evidence for maintaining full dose on schedule (FDOS) chemotherapy in CRC. To date, clinical studies have focused on determining which agents or combinations are optimal in advanced disease or the adjuvant setting. Combinations of irinotecan or oxaliplatin with 5-fluorouracil and leucovorin are currently being evaluated in the adjuvant treatment of CRC, and the addition of targeted biologic agents to standard chemotherapy regimens is being evaluated in the treatment of advanced disease. Few studies have investigated dose intensity in the adjuvant setting, and consequently, there is little evidence for a link between FDOS chemotherapy and outcomes. Nonetheless, the benefits of maintaining FDOS chemotherapy, as shown in trials in breast cancer and non-Hodgkin's lymphoma, may also hold true in CRC. Furthermore, several studies in metastatic CRC have found that greater survival can be achieved with dose-intensified chemotherapy. If FDOS chemotherapy is to become accepted in the treatment of CRC, end points other than overall survival may have to be assessed in metastatic disease and the concept will have to be investigated in the adjuvant setting. For now, the role of FDOS chemotherapy in CRC has not been adequately evaluated.