Abstract
Systemic therapy is the standard care for patients with unresectable advanced colorectal cancer (CRC), but salvage surgery of metastatic disease should be considered in the case of adequate tumor shrinkage. Several drugs and combinations are now available for use in treating patients with advanced CRC, but the optimal sequence of therapy remains unknown. Moreover, the administration of antitumor therapy can be modulated by periods of maintenance or treatment breaks rather than delivered as full therapy until disease progression or unacceptable toxicity, followed by reintroduction of prior full therapy when required, before switching to other drugs. Consequently, randomized strategy trials are needed to define the optimal treatment sequences. Molecular testing for Kirsten rat sarcoma viral oncogene homolog (KRAS) and neuroblastoma RAS viral oncogene homolog (NRAS) is mandatory but not sufficient to select appropriate patients for epidermal growth factor receptor (EGFR) monoclonal antibody (MoAb) therapy.