The primary objectives of this study will determine the following: the response rate (including pathological CR rate), TTP, and complications of treatment in patients with rectal cancer treated with FOLFOX bevacizumab, the alteration of tumor blood flow (assessed by DCE-MRI as percentage change in Ktrans) after 1 cycle of bevacizumab therapy compared to baseline value in patients treated with FOLFOX alone and those treated with bevacizumab at 5 mg/kg., the degree of hypoxis (measured by tumor uptake of the 2-nitroimidazole EF5) induced by bevacizumab treatment and its relationship to changes in tumor blood flow, and the degree of apoptosis (measured by tumor uptake of di-annexin V) induced by bevacizumab treatment and its relationship to changes in tumor blood flow. The secondary objectives of this study is to determine in an exploratory fashion the relationship between tumor blood flow, hypoxia induction, and apoptosis induction , and time to progression in patients continuing on to receive Bevacizumab 5 mg/kg, to analyze archival tumor from the patients treated in this trial for mutations in the MKK7 and SEK1 genes, and by semi-quantitative IHC for these and other relevant proteins, to determine the relationship between vascular proliferation as measured by DCE-MRI and markers of endothelial cell proliferation, and to obtain pilot data on whether assays that measure vascular endothelial cell mitogenic stimulation and mitogenic activity may predict response to therapy, time to progression and overall survival in patients receiving bevacizumab 5 mg/kg.
This study will determine the following: the response rate (including pathological CR rate), TTP, and complications of treatment in patients with rectal cancer treated with FOLFOX bevacizumab, the alteration of tumor blood flow (assessed by DCE-MRI as percentage change in Ktrans) after 1 cycle of bevacizumab therapy compared to baseline value in patients treated with FOLFOX alone and those treated with bevacizumab at 5 mg/kg., the degree of hypoxis (measured by tumor uptake of the 2-nitroimidazole EF5) induced by bevacizumab treatment and its relationship to changes in tumor blood flow, and the degree of apoptosis (measured by tumor uptake of di-annexin V) induced by bevacizumab treatment and its relationship to changes in tumor blood flow.