Preoporative Bevacizumab, Radiation Therapy, and XELOX Chemotherapy for Locally Advanced Nonmetastatic Rectal Cancer

Inclusion Criteria: * Histologically confirmed adenocarcinoma of the colon or rectum. * T3 or T4 adenocarcinoma or node positive colorectal tumours. * Appropriate staging investigations of the primary tumour, either endorectal ultrasound or pelvic MRI. * Male or female aged 18 to 70. * Have a performance status ECOG of 0 or 1. * Have a life expectancy greater than 6 months. * Adequate organ function and coagulation parameters as measured by: WBC \> 4000/mm3, PLT \> 100000/mm3, Hb \> 10g/dL, ALT \< 1.5X ULN, AST \< 1.5X ULN, bilirubin \< 1.5mg/dL Serum creatinine \< 1.8mg/dL. * Patient consent. Exclusion Criteria: * Known to have clinical or radiological evidence of distant metastases. * Evidence of intestinal obstruction (except for those after enterostomy). * Patients with a past history of colorectal surgery (except for enterostomy), chemtherapy, radiation, biotherapy or targeted therapy. * Pregnant woman OR women of childbearing potential with a positive pregnancy test at baseline or lactating. * Sexually active males and females (of childbearing potential) unwilling to practice contraception during the study. * Patients with a past or current history (within last 5 years) of other malignancies, except for the indication under this study and curatively treated basal and squamous skin cancer or in-situ cancer of the cervix. * Patients with mental disorder unable to complete the informed consent. * Uncontrolled hypertension. * Clinically significant (i.e. active) cardiovascular disease for example: cerebrovascular accidents (\<=6 months), myocardial infarction (\<= 6 months), unstable angina, New York Heart Association (NYHA) grade II or greater congestive heart failure, serious cardiac arrhythmia requiring medication. * Moderate or serious proteinuria. * Known hypersensitivity against experimental drugs.