Xeloda Vs Monitoring in Advanced Colorectal Cancer Responsive to Chemotherapy

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