Arm OFF: Patients receive oxaliplatin 85 mg/m^2 (iv, 2 hours) on days 8 and 22 with 42 days as a cycle. Patients receive folinic acid 200 mg/m^2 (iv) and fluorouracil 2000 mg/m^2 (iv, 24 hours) on days 1, 8, 15 and 22 for 4 weeks, followed by 2 weeks without treatment. Oxaliplatin is given before folinic acid and fluorouracil when the three drugs are given on the same days. Treatment repeats until there is disease progression or recurrence.