DISEASE CHARACTERISTICS:

• Diagnosis of breast cancer

  • T2-T4c, any N, M0 disease

• Clinically staged, as documented by the operating surgeon, as 1 of the following:

  • T4a-c disease for which modified radical mastectomy with negative margins is the goal
  • T2 or T3 disease for which conversion from needing mastectomy to breast conservation is the goal
  • T2 disease for which lumpectomy at first attempt is the goal
• Primary tumor must be palpable and measure 2 cm by caliper measurements in at least one dimension
• Must agree to undergo mastectomy or lumpectomy after neoadjuvant aromatase inhibitor therapy
• No inflammatory breast cancer, defined as clinically significant erythema of the breast and/or documented dermal lymphatic invasion (not direct skin invasion by tumor or peau d'orange without erythema)

• No distant metastasis (M1)

  • Isolated ipsilateral supraclavicular node involvement allowed
• Must have estrogen receptor (ER) positive tumor with an Allred score of 6, 7 or 8

PATIENT CHARACTERISTICS:

• ECOG/Zubrod performance status of ≤ 2
• Female

• Patient must be postmenopausal, verified by 1 of the following:

  • Bilateral surgical oophorectomy
  • No spontaneous menses > 1 year
  • No menses for < 1 year with FSH and estradiol levels in postmenopausal range

• If patient is a cancer survivor, all of the following criteria must be met:

  • Must have undergone potentially curative therapy for all prior malignancies
  • No evidence of any prior malignancies for at least 5 years with no evidence of recurrence (except for successfully treated cervical carcinoma in situ, lobular carcinoma in situ of the breast, or non-melanoma skin cancer with no evidence of recurrence)
  • Deemed by their treating physician to be at low risk for recurrence

PRIOR CONCURRENT THERAPY:

• Any agent with estrogenic or putatively estrogenic properties, including herbal preparations, must be stopped at least one week prior to registration
• No prior treatment for breast cancer, including radiation, endocrine therapy, chemotherapy, or investigational agent
• No concurrent enrollment in another neoadjuvant clinical trial for treatment of the existing breast cancer
• No hormone replacement therapy of any type, megestrol acetate, or raloxifene within one week prior to registration
• No other concurrent anti-neoplastic approach such as chemotherapy or radiation therapy
• Concomitant use of agents and herbal products that alter ER function are specifically not allowed