To compare maintenance chemotherapy with Xeloda to control after best response with first line chemotherapy in advanced colorectal cancer. Main endpoint is progression free survival. A total of 300 patients will be included.

Inclusion Criteria:

• Patients with metastatic colorectal cancer (confirmed histologically) with objective response or stabilization after at least 6 cycles of first line chemotherapy (treatment of choice is selected freely by the investigator according to the recommendations and consensus in force),
• The interval between completion of first line chemotherapy and randomization should not exceed 4 weeks
• Age>18 years
• ECOG status 0 to 2
• Biological criteria prior to any chemotherapy:

Neutrophils>1.5 109 g/l, platelets>100 109/l, haemoglobin>10 g/dl, Creatininaemia<150 mol/l, bilirubinaemia<2x normal level

• Signed informed consent
• Life expectancy > 3 months

Exclusion Criteria:

• Metastatic colorectal cancer treated with more than one modality of first line chemotherapy (including oral fluoropyrimidines)
• Tumour progression after first line chemotherapy or before randomization
• Other tumour pathology
• Symptomatic cerebral metastases
• Any severe uncontrolled disease in addition to colorectal cancer (in particular decompensated cardiac failure (LVEF<50%) or coronary insufficiency)
• Lack of integrity of the upper GI tract: malabsorption syndrome or major surgery of the stomach or the small intestine
• Severe renal impairment (creatinine clearance < 30 ml/min)
• Severe psychiatric disorder (other than controlled depressive syndrome)
• Patient participating in another experiment
• Pregnant women