Current approaches to first-line treatment of advanced colorectal cancer.

The multiplicity of chemotherapy regimens currently available to treat colorectal cancer in the first-line setting precludes the identification of a single standard regimen for front-line therapy. The previous standard, 5-fluorouracil (5-FU), formerly the only agent with any significant activity against colorectal cancer, is now the base for newer combination regimens that are improving survival in this disease. When irinotecan and oxaliplatin were proven to be active in colorectal cancer, the pursuit of combination regimens began. Targeted agents such as bevacizumab also show activity and improve the outcome of 5-FU-based regimens. The history and development of 5-FU-based treatment regimens that include the newer drugs irinotecan, oxaliplatin, and bevacizumab are discussed in light of the impact these advances have made in the treatment of colorectal cancer