New strategies for treatment of KRAS mutant metastatic colorectal cancer.

The introduction of new cytotoxic agents and new targeted therapies has significantly broadened the therapeutic options for and the outcomes of patients with metastatic colorectal cancer (CRC). The introduction of the anti-epidermal growth factor receptor (EGFR) antibodies, cetuximab and panitumumab, has clearly contributed to this development. The concept of KRAS as a marker for resistance to anti-EGFR antibodies has been validated. However, new challenges have emerged: the complete understanding of the crucial and central role of KRAS in processes of tumor growth and the development of new treatment strategies for KRAS mutant tumors. KRAS seems to be so crucial that a further classification and description in KRAS wild-type and mutant may be warranted. Testing for KRAS mutations marks, therefore, a paradigm shift in the management of metastatic CRC. This testing also highlights the unmet need for new treatment options in KRAS mutant metastatic CRC. In this review we will focus on possible new treatment options for these patients.