Letrozole in Preventing Cancer in Postmenopausal Women Who Have Received 4-6 Years of Hormone Therapy for Hormone Receptor-Positive, Lymph Node-Positive, Early-Stage Breast Cancer

You may be eligible if

• DISEASE CHARACTERISTICS:
• Confirmed diagnosis of prior operable, noninflammatory breast cancer meeting the following criteria:
• * Steroid hormone receptor-positive tumors (estrogen receptor and/or progesterone receptor), determined by immunohistochemistry, after primary surgery and before commencement of prior endocrine therapy
• * Prior local treatment including surgery with or without radiotherapy for primary breast cancer with no known clinical residual loco-regional disease
• * Following primary surgery, eligible patients must have had evidence of lymph node involvement either in the axillary or internal mammary nodes, but not supraclavicular nodes
• * Clinically disease-free
• Must have completed 4-6 years of prior adjuvant selective estrogen receptor modulators (SERMs), aromatase inhibitors (AIs), or a sequential combination of both
• * When calculating 4-6 years, neoadjuvant endocrine therapy should not be included
• No evidence of recurrent disease or distant metastatic disease
• No prior bilateral breast cancer
• PATIENT CHARACTERISTICS:
• Female
• Must be postmenopausal by any of the following criteria:
• * Patients of any age who have had a bilateral oophorectomy (including radiation castration AND amenorrheic for \> 3 months)
• * Patients 56 years old or older with any evidence of ovarian function must have biochemical evidence of definite postmenopausal status (defined as estradiol, luteinizing hormone \[LH\], and follicle-stimulating hormone \[FSH\] in the postmenopausal range)
• * Patients 55 years old or younger must have biochemical evidence of definite postmenopausal status (defined as estradiol, LH, and FSH in the postmenopausal range)
• Clinically adequate hepatic function
• No bone fracture due to osteoporosis at any time during the 4-6 years of prior therapy
• No prior or current malignancy except adequately treated basal cell or squamous cell carcinoma of the skin, in situ carcinoma of the cervix or bladder, or contra- or ipsilateral in situ breast carcinoma
• No other nonmalignant systemic diseases (cardiovascular, renal, lung, etc.) that would prevent prolonged follow-up
• No psychiatric, addictive, or any other disorder that compromises compliance with protocol requirements
• PRIOR CONCURRENT THERAPY:
• See Disease Characteristics
• More than 12 months since prior and no other concurrent endocrine SERM/AI therapy
• Any type of prior adjuvant therapy allowed including, but not limited to, any of the following:
• * Neoadjuvant chemotherapy
• * Neoadjuvant endocrine therapy
• * Adjuvant chemotherapy
• * Trastuzumab (Herceptin®)
• * Ovarian ablation
• * Gonadotropin releasing hormone analogues
• * Lapatinib ditosylate
• No concurrent hormone-replacement therapy, bisphosphonates (except for treatment of bone loss), or any other investigational agent