迄今,氟尿嘧啶(fluorouracil)仍是治疗结肠癌唯一有效的全身化疗药物。氟尿嘧啶主要通过抑制DNA合成的一个关键酶-胸苷酸合成酶而发挥作用,由于甲酰四氢叶酸(leu- covorin)可增强这种效应,通常氟尿嘧啶和甲酰四氢叶酸联合应用,简称FL方案。FL有多种不同剂量的化疗方案,通常持续给药的效果稍优于一次给药。大约20%的结肠癌进展期患者,FL可使其肿瘤缩小50%以上,FL还可将中位生存 To date, fluorouracil remains the only systemic chemotherapy drug that is effective in treating colon cancer. Fluorouracil mainly through a key enzyme that inhibits DNA synthesis - thymidylate synthase to play a role, due to leu-covorin can enhance this effect, usually fluorouracil and leucovorin in combination, referred to as FL Program. There are a number of different doses of chemotherapy regimens that are usually administered more consistently than once. Approximately 20% of patients with advanced colon cancer, FL can reduce its tumor more than 50%, FL can also be the median survival