Inclusion Criteria:

- Histologically confirmed operable or potentially operable invasive breast
adenocarcinoma that is clinically palpable and measurable

- Age ≥ 18 years

- Clinical Stage T2-4, N0-3, M0 (Stage II-III)

- Postmenopausal defined as Age ≥ 60 years and/or Age >45 years with amenorrhea 12
months with an intact uterus and/or History of bilateral oophorectomy and/or FSH and
estradiol levels in postmenopausal range

- ECOG PS 0, 1

- Unifocal disease

- ER and/or PR positive

- Adequate hematological, renal, and hepatic functions Absolute neutrophil count ≥
1,500/µL Platelet count ≥ 100,000/µL creatinine ≤ 1.5 mg/dL Serum total bilirubin ≤
1.5 mg/dL Alkaline phosphatase ≤ 3X the ULN for the reference lab SGOT/SGPT ≤ 3X the
ULN for the reference lab

- Patients or their legal representatives must be able to read, understand and provide
informed consent to participate in the trial

- Use of effective means of contraception (men and women) in subjects of child-bearing
potential

Exclusion Criteria:

- Prior history of and/or therapy for invasive breast cancer (includes chemotherapy,
radiation, hormonal therapy including AIs, tamoxifen, raloxifene, fulvestrant or any
other antiestrogen/SERM)

- Clinically significant cardiovascular disease, EF <50%

- Known CNS disease

- History of deep vein thrombosis or pulmonary embolism

- Proteinuria at screening as demonstrated by either Urine protein:creatinine (UPC)
ratio ≥ 1.0 at screening OR Urine dipstick for proteinuria ≥ 2+ (patients discovered
to have ≥2+ proteinuria on dipstick urinalysis at baseline should undergo a 24 hour
urine collection and must demonstrate ≤ 1g of protein in 24 hours to be eligible).

- Presence of non-healing wound or fracture

- Current, recent (within 4 weeks of the first infusion of this study), or planned
participation in an experimental drug study other than a Genentech-sponsored
bevacizumab cancer study

- Inadequately controlled hypertension (defined as systolic blood pressure >150 and/or
diastolic blood pressure > 100 mmHg on antihypertensive medications)

- Any prior history of hypertensive crisis or hypertensive encephalopathy

- New York Heart Association (NYHA) Grade II or greater congestive heart failure (see
Appendix E)

- History of myocardial infarction or unstable angina within 12 months prior to study
enrollment

- Any history of stroke or transient ischemic attack at any time

- Significant vascular disease (e.g., aortic aneurysm, aortic dissection)

- Symptomatic peripheral vascular disease

- Evidence of bleeding diathesis or coagulopathy

- Major surgical procedure, open biopsy, or significant traumatic injury within 28 days
prior to Day 0

- Core biopsy or other minor surgical procedures such as fine needle aspirations or
core biopsies within 7 days prior to Day 0

- Pregnant (positive pregnancy test) or lactating. Use of effective means of
contraception (men and women) in subjects of child-bearing potential is mandatory

- History of abdominal fistula, gastrointestinal perforation, or intra-abdominal
abscess within 6 months prior to Day 0

- Known hypersensitivity to any component of bevacizumab or letrozole

- Inability to comply with study and/or follow-up procedures