Two Steps Forward in the Treatment of Colorectal Cancer

Until recently, fluorouracil was the only effective systemic treatment for colorectal cancer. It acts primarily by inhibiting thymidylate synthase, a key enzyme in DNA synthesis, and because leucovorin (folinic acid) enhances this effect, fluorouracil and leucovorin (FL) are given together. FL has been given in various dose schedules, with a continuous infusion appearing slightly more effective than a bolus.1 FL reduces tumor size by 50 percent or more (objective response) in approximately 20 percent of patients with advanced colorectal cancer and prolongs median survival from approximately 6 months (without treatment) to about 11 months.2 When given as adjuvant therapy after . . .