More than three quarter of patients with breast cancer are treated by hormone pills called
tamoxifen and aromatase inhibitors (AIs). AIs are drugs that stop female hormone production.
This hormone production mostly happens in fat, muscle, and breast tissue in postmenopausal
women. The female hormone estrogen is an important hormone for the growth of breast cancer
cells. Anastrozole (Arimidex) and Letrozole (Femara) are AIs that are approved by the Food
and Drug Administration (FDA). They have been used since 2005 to treat women with early
stage breast cancer.
When given before surgery (neoadjuvant), both anastrozole and letrozole have been shown to
successfully shrink breast cancer tumors in most patients. In over 50% of patients,
anastrozole and letrozole when given for about 4 months also helped to improve surgery
outcomes. On top of that, whether or not a patient responds to anastrozole and letrozole
before surgery can help the doctor decide whether that patient needs additional
One of the things may influence the level of hormone is body weight. It has been previously
shown that postmenopausal women with higher body fat have higher level of female hormone as
well as an increased risk of breast cancer. This is likely due to an increase in aromatase
activity in the fatty tissue. However, at the current time AIs are used at the same doses in
all women with breast cancer no matter whether they have different body weight. Currently,
we do not know for certain whether the same doses of AIs work as well in patients with
higher body fat compared to patients with less body fat.
The purpose of this study is to see if women with higher body fat respond differently to AI
treatment compared to women with lower body fat.
1. Female greater than or equal to 18 years.
2. Histologically confirmed or presumptive or previously defined adenocarcinoma of the
3. Evidence of hormone sensitivity (estrogen receptor [ER] and/or progesterone receptor
[PR] 1%) of primary tumor tissue.
4. Human estrogen receptor -2 (HER2) negative in the primary tumor tissue as defined
1. Grade 0 or 1+ staining intensity (on a scale of 0 to 3) by means of IHC analysis
2. Grade 2+ staining intensity by means of immuno-histochemical (IHC) analysis with
gene amplification on fluorescence in situ hybridization (FISH) < 2.0 OR
3. Gene amplification on fluorescence in situ hybridization (FISH) < 2.0.
5. Eastern Cooperative Oncology Group (ECOG) performance status 3
6. Unresected operable presumptive or previously defined breast cancer stage I-III with
primary tumor 1.0 cm.
7. Ability to understand and the willingness to sign a written informed consent
8. Patients must not have received any prior chemotherapy, radiation therapy, or
endocrine therapy for their current breast cancer. Patients who received tamoxifen or
raloxifene or another agent for prevention of breast cancer may be included as long
as the patient has discontinued the treatment at least one month prior to baseline
9. Patients must have an adequate tumor tissue sample prior to enrollment available for
correlative studies as defined below: Core needle biopsy or incisional biopsy samples
that can provide 5 unstained sections of 5 micron thickness. Fine needle aspiration
(FNA) sample alone is not sufficient.
10. Patients must have adequate organ function as defined below:
1. Total bilirubin within normal institutional limits
2. aspartate aminotransferase (AST)(SGOT)/alanine aminotransferase (ALT)(SGPT) <
2.5 x institutional upper limit of normal
3. Creatinine clearance 10 mL/min/1.73 m2
1. Previous or current systemic malignancy within the past 3 years other than breast
cancer or adequately treated cervical carcinoma in situ or basal/squamous carcinoma
of the skin.
2. Patients may not be receiving any other investigational agent.
3. History of allergic reactions or hypersensitivity to compounds of similar chemical or
biologic composition to anastrozole.
Minimum Eligible Age: 18 Years
Maximum Eligible Age: N/A
Eligible Gender: Female