Aflibercept +/- LV5FU2 in First Line of Non-resectalbe Metastatic Colorectal Cancers

Inclusion Criteria: * Age ≥ 65 years * General condition WHO ≤ 2 * Metastatic rectal or colonic adenocarcinoma, histologically proved on the primary tumour or a metastasis * Metastases non-resectable and/or patient inoperable * patients where a single agent chemotherapy combined with an anti-angiogenic agent is an appropriate approach * At least one measurable target according to RECIST v1.1 criteria, no previously irradiated * No previous treatment of the metastatic disease. Previous chemotherapy in an adjuvant situation completed 6 months or more before diagnosis of the metastasis is authorized. * Adequate biological examination: Hb \> or = 9 g/dl, polynuclear neutrophils \> or = 1,500/mm3, platelets \> or =100,000/mm3, total bilirubin \< or = 1.5 x UNL, creatinine clearance, calculated according to Cockroft-Gault formula, \> 50 ml/min creatininemia \< 1.5 x UNL, ALP \< 5 x UNL, transaminases \< 5 x ULN, GGT\< 5 x UNL * Proteinuria (strip) \< 2+; if \> or = 2+, test proteinuria over 24 hours which must be ≤ 1 g. * Central genotyping of thymidylate synthase (TS) in blood DNA * Patients treated with anticoagulants (coumadin, warfarin) can be included if the INR can be closely monitored. A change in anticoagulant treatment for low molecular weight heparin is preferable in order to respect indications * Signed written informed consent obtained prior to inclusion Exclusion Criteria: * Patients with a primary tumour in place and presenting clinical symptoms (occlusion, haemorrhage) * History of brain metastases, uncontrolled spinal cord compression, or carcinomatous meningitis or new evidence of brain or leptomeningeal disease. * Uncontrolled hypercalcemia * Uncontrolled hypertension (SBP \> 150 mmHg and DBP \> 100 mmHg) or history of hypertensive attacks or hypertensive encephalopathy * Any progressive pathology not balanced over the past 6 months: hepatic insufficiency, renal insufficiency, respiratory insufficiency, * Any of the following within 6 months prior to inclusion: myocardial infarction, severe/unstable angina pectoris, coronary/peripheral artery bypass graft, NYHA class III or IV congestive heart failure, stroke or transient ischemic attack. * Any of the following within 3 months prior to inclusion: Grade 3-4 gastrointestinal bleeding/hemorrhage, treatment resistant peptic ulcer disease, erosive oesophagitis or gastritis, infectious or inflammatory bowel disease, diverticulitis, pulmonary embolism or other uncontrolled thromboembolic event, wound or fractured bone * Major surgery during the 28 days preceding the start of treatment * Known acquired immunodeficiency syndrome (AIDS-related illnesses) or known HIV disease requiring antiretroviral treatment. * Treatment with concomitant anticonvulsivant agents that are CYP3A4 inducers (phenytoin, phenobarbital, carbamazepine), unless discontinued \>7 days. * Anti-tumoral treatments other than the trial treatments (chemotherapy, targeted therapy, immunotherapy) * Macronodular peritoneal carcinosis (risk of perforation) * Known DPD deficit * Prior history of malignant haemopathy or cancer except those treated more than 5 years ago and considered to be cured, in situ cervical carcinomas and treated skin cancers (excluding melanoma) * Patients on new oral anticoagulant therapy (rivaroxaban XARELTOR, apixaban ELIQUIS, dagigatran PRADAXA except if relay by vitamine K antagonist therapy) * Any contraindication to the treatments used in the trial * Impossibility of undergoing medical monitoring during the trial for geographic, social or psychological reasons