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