Predictive Markers in Colorectal Cancer

In 2008, the optimal treatment for colorectal cancer remains unsettled. In the metastatic setting, several drugs are approved and commonly used; 5-fluorouracil, irinotecan, oxaliplatin, bevacizumab, cetuximab and panitumumab. Improvements in survival have been observed with combination of these agents although questions persist-which combination of agents is the best drug regimen, when is the most appropriate time for their use, and which regimen is the most cost-effective and manageable in terms of toxicities? The resolution of these issues requires the identification of markers capable of predicting which patients are most likely to benefit and avoid untoward side effects. Advances in the predictive marker field have recently been made especially in regards to K-RAS status in the use of EGFR monoclonal antibodies. Work on other potential predictors is ongoing. This review examines the current knowledge of predictive markers for drugs approved for colorectal cancer.