Inclusion Criteria:  Patient at least 18 years old, Patient with colorectal cancer of the adenocarcinoma type, stage IV, histologically confirmed, mutated or wild tumor RAS status (exons 2, 3 and 4 of the KRAS and NRAS genes), mutated or wild BRAF status, naive in antineoplastic treatment Patient eligible to start systemic carcinological treatment including bevacizumab in combination with chemotherapy based on IV fluoropyrimidine, General condition WHO grade less than or equal to 3, Life expectancy greater than 4 months, Patient who has read and understood the information letter and signed the consent form, Patient affiliated to a social security scheme, Effective contraception (see WHO definition) in women of childbearing age (negative pregnancy test). For postmenopausal women, a confirmatory diagnosis should be obtained (amenorrhea not medically induced for at least 12 months before the inclusion visit).  Exclusion Criteria:  Previous exposure to anti-VEGF, Exposure to treatment for metastatic disease in the 12 months prior to inclusion, Other histologically proven neoplasia not considered in complete remission or considered in complete remission for less than two years, Bilateral carotid breath, Absence of peripheral pulse of the two upper limbs,  Contraindication to AVASTIN 25 mg / ml concentrate for solution for infusion:  Hypersensitivity to the active substance or to any of the excipients, Hypersensitivity to Chinese hamster ovarian cell products or other human or humanized recombinant antibodies,  Patients:  having undergone a major surgical intervention in the 28 days preceding the inclusion or as long as the surgical wound is not completely healed, Unhealed ulcer or wound, having uncontrolled pre-existing hypertension (PAS> or = 170 mm Hg after three repeated measurements at rest), having a history of arterial thromboembolism (transient ischemic attack (TIA), cardiovascular accident (stroke) or recent (<6 months) and / or symptomatic myocardial infarction (MI) having had an invasive dental procedure in the 28 days preceding inclusion, with known proteinuria> 2g / 24h or in whom proteinuria> 2g / 24h is discovered in the case of a positive urine strip 3+ for proteins (excluding urinary tract infection), on aspirin> 325 mg / d, with a colonic prosthesis in place, Systemic treatment with anti-EGFR monoclonal antibodies, Presence or history of lymphedema of the bilateral upper limbs, Patient with poor understanding of spoken or written French, Patient deprived of liberty by an administrative or judicial decision or patient placed under the protection of justice, under guardianship or curatorship, Pregnant or lactating woman or wishing to breastfeed within 6 months after the last administration of the treatment, Patient participating in another drug trial / having participated in another drug trial within 30 days of inclusion, History of illness or psychological or sensory abnormality likely to prevent the subject from fully understanding the conditions required for his participation