<qa>  What is the maximum tolerated dose of a VEGF neutralizing antibody?I. To determine the maximum tolerated dose MTD of a vascular endothelial growth factor VEGF neutralizing antibody, bevacizumab, when administered concurrently with 5-fluorouracil 5-FU and external beam radiation therapy EBRT in patients with clinical stage T3 or T4 rectal cancer prior to surgery. 