Current therapies for advanced colorectal cancer

Significant advances have been made in the treatment of advanced colorectal cancer over the past 5 years, namely due to the introduction of three novel cytotoxic agents-capecitabine (Xeloda), irinotecan (Camptosar), and oxaliplatin (Eloxatin)-and the recent approval of two biologic agents-bevacizumab (Avastin) and cetuximab (Erbitux). During this time period, the median survival of patients with advanced, metastatic disease has gone from 10 to 12 months to nearly 24 months. Intense efforts have focused on identifying novel targeted therapies that target specific growth factor receptors, critical signal transduction pathways, and/or key pathways that mediate the process of angiogenesis. Recent clinical trial results suggest that the anti-VEGF antibody bevacizumab can be safely and effectively used in combination with each of the active anticancer agents used in colorectal cancer. Despite the development of active combination regimens, significant improvements in the actual cure rate have not yet been achieved. Combination regimens with activity in advanced disease are being evaluated in the adjuvant and neoadjuvant settings. The goal is to integrate these targeted strategies into standard chemotherapy regimens so as to advance the therapeutic options for the treatment of advanced colorectal cancer. Finally, intense efforts are attempting to identify the critical molecular biomarkers that can be used to predict for either clinical response to chemotherapy and/or targeted therapies and/or the drug-specific side effects. The goal of such studies is to facilitate the evolution of empiric chemotherapy to individually tailored treatments for patients with colorectal cancer.