 Based on the astonishing high response rate in metastatic colorectal cancer in weekly high dose 5-FU and leucovorin, we will conduct a clinical trial to clarify the activity of this regimen in the adjuvant setting. The regimen of 5-FU and high dose leucovorin administered as the schedule of INT-0089 will be chosen as the controlled arm which was proven as effective as standard 5-FU plus levamisole regimen with short duration of treatment.21 In this study, continuous infusion of 5-FU HDFL, Arm B and bolus injection of 5-FU Arm A will be administered to the high risk colon cancerN2 disease patients. The role of TS level and inhibition of TS as a predictor of adjuvant chemotherapy with 5-FU based treatment will be clearly defined prospectively. 