An overview of adjuvant systemic chemotherapy for colon cancer.

This article summarizes the progress of adjuvant systemic chemotherapy of colon cancer. The study by Moertel et al that showed that the combination of 5-fluorouracil (5-FU) and levamisole in the adjuvant setting reduced mortality by 33% in stage III colon cancer; 5-FU/leucovorin (LV) became the standard of care in the adjuvant treatment of colon cancer after it showed superiority to 5-FU/levamisole. However, no standard schedule of 5-FU/LV has been established. The fortnightly regimen of bolus 5-FU/LV and continuous infusion 5-FU (LV5FU2) has the same efficacy as and is less toxic than the monthly regimen of bolus 5-FU/LV. Oxaliplatin combined with 5-FU and LV (FOLFOX4) is the first combination to demonstrate significant superiority in 3-year disease-free survival as compared with 5-FU/LV in the adjuvant treatment of colon cancer. Three-year disease-free survival is an excellent predictor of 5-year overall survival and, in future studies, can serve as a reliable endpoint that is associated with reproducible 5-year overall survival. Results of studies testing irinotecan combined with 5-FU and LV are not yet available. Adjuvant chemotherapy for patients with stage II colon cancer is a controversial subject. Because the available data suggest that stage II patients benefit from adjuvant chemotherapy, although to a lesser extent than patients with stage III disease, all patients with stage III and high-risk stage II disease should be offered adjuvant treatment with the new standard of care, FOLFOX4. Future studies in adjuvant therapy for colon cancer will explore oxaliplatin and 5-FU with or without antiangiogenesis or anti-epidermal growth factor agents.