Anastrozole or Letrozole before Surgery in Treating Patients with Hormone Receptor Positive Stage II-III Breast Cancer That Can Be Removed by Surgery

PRIMARY OBJECTIVES:

I. To evaluate the percent change in proliferative index (Ki67) in the primary breast tumor after neoadjuvant treatment with standard dose anastrozole or letrozole in normal, overweight, and obese patients with estrogen receptor (ER) positive breast cancer (T2-3, N0/1, M0).

SECONDARY OBJECTIVES:

I. To assess estradiol levels at baseline and after treatment with standard dose anastrozole or letrozole in normal, overweight, and obese patients.

II. To evaluate differences in baseline PC cell-derived growth factor (GP88) level and Oncotype Dx assay in primary ER positive breast tumors from normal, overweight, and obese patients.

III. To evaluate the association of aromatase inhibitor (AI)-induced Ki67 response with baseline and post treatment GP88 level and baseline Oncotype Dx assay in normal, overweight, and obese patients.

EXPLORATORY OBJECTIVES:

I. To assess circulating and infiltrating immunoregulatory cells (IRC) at baseline and after treatment with standard dose anastrozole or letrozole in normal, overweight, and obese patients. (optional when feasible)

II. To evaluate local and circulating pro-inflammatory cytokines at baseline and after treatment with standard dose anastrozole or letrozole in normal, overweight, and obese patients. (optional when feasible)

OUTLINE: Patients are assigned to 1 of 2 arms.

ARM I: Patients receive anastrozole orally (PO) once daily (QD) for 14-28 days in the absence of disease progression or unacceptable toxicity. Treatment may continue for up to 18 weeks at the discretion of the treating physician. Within 36 hours after the last dose of anastrozole, patients undergo surgery. Patients undergo mammography, breast ultrasound, and breast magnetic resonance imaging (MRI) as clinically indicated. Patients also undergo blood sample collection and tissue biopsy on the trial.

ARM II: Patients receive letrozole PO QD for 14-28 days in the absence of disease progression or unacceptable toxicity. Treatment may continue for up to 18 weeks at the discretion of the treating physician. Within 36 hours after the last dose of letrozole, patients undergo surgery. Patients undergo mammography, breast ultrasound, and breast MRI as clinically indicated. Patients also undergo blood sample collection and tissue biopsy on the trial.

After completion of study treatment, patients are followed up for 30 days.