Metastatic colorectal cancer: current systemic treatment options

The treatment of colorectal cancer has become increasingly complex over recent years. With the emergence of new chemotherapy drugs and targeted agents, there has been great improvement in the prognosis of patients with metastatic colorectal cancer. This review summarises the evidence supporting the use of combination chemotherapy with oxaliplatin and/or irinotecan with fluorouracil (5-FU) for the treatment of colorectal cancer and outlines the pivotal trials. Phase III trials have demonstrated the superiority of combination chemotherapy over single-agent 5-FU, but the optimal sequencing and combination of treatment is yet to be determined. Oral fluoropyrimidine derivatives have been shown to be equivalent to bolus 5-FU treatment and these offer another option for the treatment of colorectal cancer, but further studies are required to evaluate their use with irinotecan and oxaliplatin. The use of newer targeted therapies, such as bevacizumab and cetuximab, alone and in combination with chemotherapy are discussed, and the most recent data supporting their use is outlined. Bevacizumab-containing regimens have been shown to be superior to those without for the first-line treatment of colorectal cancer, and cetuximab has demonstrated activity in combination with chemotherapy in both the first- and second-line setting. Other targeted agents, such as vatalanib and panitumumab, are discussed and early clinical studies with these agents show promising results.