FOLFOX-4 3months Versus 6 Months and Bevacizumab as Adjuvant Therapy for Patients With Stage II/III Colon Cancer

Inclusion Criteria: * Histologically confirmed AJCC/UICC high-risk stage II or stage III colon cancer . High-risk stage III patients (T4, N+, M0, or any T, N2, M0) may also be further randomized in the BEV study (plus or minus BEV) * Stage II patients have to be considered at high-risk if they fulfill \>1 of the following criteria: * T4 tumours, * grade \>3, * clinical presentation with bowel obstruction or perforation, * histological signs of vascular or lymphatic or perineural invasion, * \<12 nodes examined * Age 18 to 75 years * Curative surgery no less than 3 ( 4 in the BEV study) and no more than 8 weeks prior to randomization * ECOG performance Status (ECOG-PS) \<1 * Signed written informed consent obtained prior to any study specific procedures Exclusion Criteria: * Macroscopic or microscopic evidence of residual tumor (R1 or R2 resections). * Previous anti-angiogenic treatment for any malignancy; cytotoxic chemotherapy, radiotherapy or immunotherapy for colon cancer * Other malignancies within the last 5 years (other than curatively treated basal cell carcinoma of the skin and/or in situ carcinoma of the cervix) * Lactating women * Fertile women (\<2 years after last menstruation) and men of childbearing potential not willing to use effective means of contraception * History of clinically relevant psychiatric disability , precluding informed consent * Clinically relevant cardiovascular disease * History or presence of other diseases * Evidence of bleeding diathesis or coagulopathy * Current or recent (within 10 days prior to study treatment start) use of full-dose oral or parenteral anticoagulants or thrombolytic agent for therapeutic purposes * Chronic, daily treatment with high-dose aspirin (\>325 mg/day) or clopidogrel (\>75 mg/day) * Current or recent (within the 28 days prior to randomization) treatment with another investigational drug or participation in another investigational study