Colorectal cancer: how emerging molecular understanding affects treatment decisions.

The medical treatment of metastatic colorectal cancer (mCRC) has advanced significantly over the last 10 years as the result of the introduction of several active cytotoxic and biologic agents into standard clinical practice. Several recent phase III trials reported median overall survival data exceeding 30 months, an achievement inconceivable only 5 years ago.The first major step forward in the medical management of mCRC was provided by the addition of irinotecan and oxaliplatin to fluorouracil-based therapy; this increased survival from about 12 months to about 20 months.The introduction of biologic agents such as vascular endothelial growth factor inhibitors and epidermal growth factor inhibitors further increased survival--to more than 2 years in prospective trials. Recently, an expanding array of molecular prognostic and predictive biomarkers have been developed that are being integrated into clinical practice. In this review we discuss the current treatment options in metastatic colon cancer, with a special focus on biologic agents and how molecular understanding guides treatment decisions.