Letrozole in Preventing Breast Cancer in Postmenopausal Women

DISEASE CHARACTERISTICS:

At increased risk for the development or recurrence of breast cancer, defined as an estradiol level ≥ 9 pg/mL

No evidence of suspicious or malignant disease, based on the following examinations:

Clinical bilateral breast examination within the past 6 months
Bilateral* mammogram within 3 months before randomization OR within 30 days after randomization
Pelvic exam normal within the past 5 years
General physical exam within the past 6 months NOTE: *Unilateral mammogram of the uninvolved breast for patients with prior invasive breast cancer or ductal carcinoma in situ (DCIS)

Bone density scan within 2 standard deviations from normal within the past 30 days

Bone density scan ≥ 2 standard deviations below normal allowed if approved by the study physician
At least 1 breast that has not been previously treated with radiotherapy or surgery (for patients with prior invasive breast cancer or DCIS)

Hormone receptor status:

Not specified

PATIENT CHARACTERISTICS:

Age

35 and over

Sex

Female

Menopausal status

Postmenopausal, defined by any of the following criteria:

At least 12 months without spontaneous menstrual bleeding
Prior hysterectomy and bilateral salpingo-oophorectomy
≥ 55 years of age with a prior hysterectomy with or without oophorectomy
< 55 years of age with a prior hysterectomy without oophorectomy OR the status of the ovaries is unknown AND follicle-stimulating hormone (FSH) level is in the postmenopausal range

Performance status

Normal activity must not be restricted for a significant portion of the day

Life expectancy

At least 10 years

Hematopoietic

Complete blood count with differential normal

Prior benign neutropenia allowed provided the granulocyte count is ≥ 1,500/mm^3

Hepatic

Bilirubin normal
Alkaline phosphatase normal
SGOT and SGPT normal

Renal

Creatinine normal

Cardiovascular

No uncontrolled cardiovascular disease

Other

Not pregnant
No other malignancy within the past 5 years except basal cell or squamous cell skin cancer or carcinoma in situ of the cervix
No osteoporosis
No hyperlipidemia
No mental health status resulting in cognitive or emotional impairment that would preclude study participation

PRIOR CONCURRENT THERAPY:

Biologic therapy

Not specified

Chemotherapy

Not specified

Endocrine therapy

More than 30 days since prior AND no concurrent use of any of the following hormonal agents:

Estrogen or progesterone replacement therapy
Oral contraceptives
Raloxifene or other plasma estrogen receptor modulators (SERMs)
Androgens (e.g., danazol)
Luteinizing hormone-releasing hormone (LHRH) analogs (e.g., goserelin or leuprolide)
Prolactin inhibitors (e.g., bromocriptine)
Antiandrogens (e.g., cyproterone)
More than 60 days since prior AND no concurrent tamoxifen
No prior aromatase inhibitors (for patients with prior invasive breast cancer or DCIS)

No concurrent phytoestrogenic dietary supplements (e.g., soy, ginseng, or other natural products)

Dietary soy allowed

Radiotherapy

See Disease Characteristics

Surgery

See Disease Characteristics
No prior bilateral mastectomy

Other

More than 60 days since prior treatment for invasive breast cancer or DCIS
More than 30 days since prior bisphosphonates or calcitonin
No prior or concurrent participation on a treatment study for invasive breast cancer or DCIS
No concurrent participation in any other cancer prevention study or osteoporosis prevention study involving pharmacologic agents
No concurrent calcitonin
No concurrent bisphosphonate therapy
Concurrent cholecalciferol (vitamin D) and calcium to augment bone mineral density allowed