Comparing Letrozole Given Alone to Letrozole Given With Avastin in Post-Menopausal Women Breast Cancer

Preclinical and clinical data have demonstrated that up-regulation of tumor cell VEGF is an important mechanism to subvert estrogen dependence in hormone responsive breast cancer resulting in reduced therapy response or tumor resistance to hormonal therapy; thus, it is hypothesized that the combination of an anti-VEGF agent (Avastin, an anti-VEGF monoclonal antibody) and hormonal therapy should be more effective than hormonal therapy alone for the treatment of breast cancer.