Chemotherapy, Still an Option in the Twenty-First Century in Metastatic Colorectal Cancer?

Substantial improvements have been made in the systemic treatment of colorectal cancer over the last two decades. Median overall survival (OS) of patients with metastatic colorectal cancer (mCRC) has been constantly increased and the most recent first-line studies exceeded the 30-month median overall survival. The standard first-line regimen for mCRC is a combination of chemotherapy plus a biological agent either targeting the main angiogenic growth factor vascular endothelial growth factor (VEGF) via Bevacizumab or by antibodies targeting the epidermal growth factor receptor (EGRF) via Panitumumab or Cetuximab. Recent improvements have been shown in the efficacy of the biological agent by stratifying these agents according to the primary tumor location. In this context EGFR-inhibitors showed improved OS when used first-line in tumors derived from the left-sided colon or rectum, while tumor sidedness was not predictive for anti-VEGF-antibodies. Furthermore, the biological activity of anti-EGFR antibodies is restricted to tumors with a rat sarcoma virus (RAS)-wild-type genotype but not RAS-mutated tumors. The RAS-mutation status is not predictive for VEGF-inhibitors. Recent developments in the molecular characterisation of tumor cells led to the development of specific so called targeted therapies in colorectal cancer.