Tamoxifen in Preventing Breast Cancer in Women at Increased Risk for Breast Cancer

DISEASE CHARACTERISTICS:

• At increased risk for breast cancer, as defined by 1 of the following criteria:
• Histologically confirmed lobular carcinoma in situ (LCIS) treated by local excision only
• Composite increased breast cancer risk of ≥ 1.67% over 5 years, based on the following criteria:
• Age
• Number of first-degree female relatives with breast cancer
• One or more prior breast biopsies
• Fine-needle aspiration cytology of a non-cystic lesion in lieu of an open biopsy is considered a biopsy
• Prior diagnosis of atypical hyperplasia of the breast
• Age at first live birth
• Nulliparity
• Race
• Age at onset of menarche
• No prior or suspected invasive breast cancer or ductal carcinoma in situ
• No clinical evidence of malignancy by physical examination, including a breast examination within the past 3 months
• No evidence of suspicious or malignant disease or uncharacterized lesions on bilateral mammogram within the past 6 months
• Normal gynecologic examination, including a bimanual pelvic examination and, if indicated, pap smear within the past 12 months
• Hormone receptor status:
• Not specified

PATIENT CHARACTERISTICS:

Age

• 35 and over

Sex

• Female

Menopausal status

• Premenopausal and ovulating*, defined as having regular menses for the past 6 months OR irregular menses with follicular phase (i.e., day 3) follicle-stimulating hormone level < 20 mIU/mL OR
• Postmenopausal NOTE: * Ovulation is determined by day 21 progesterone level > 3 ng/mL

Performance status

• ECOG 0-2

Life expectancy

• Not specified

Hematopoietic

• Complete blood count normal
• No active bleeding disorder (e.g., qualitative or quantitative platelet abnormality, hemophilia, or von Willebrand's disease)

Hepatic

• Liver function tests normal

Renal

• Not specified

Cardiovascular

• No prior deep-vein thrombosis except a single occurrence related to lower extremity trauma
• No prior cerebral vascular accident
• No prior transient ischemic attack

Pulmonary

• No prior pulmonary embolus except a single occurrence related to lower extremity trauma

Other

• No saline or silicone breast implants
• No known allergy to tamoxifen
• No macular degeneration
• No malignancy within the past 5 years except basal cell or squamous cell skin cancer or carcinoma in situ of the cervix
• No nonmalignant disease that would preclude administration of tamoxifen
• No psychiatric condition, including a history of clinical depression or addictive disorder, that would preclude giving informed consent or study compliance
• Not pregnant or nursing
• Negative pregnancy test
• Fertile patients must use effective nonhormonal contraception during and for 3 months after study participation

PRIOR CONCURRENT THERAPY:

Biologic therapy

• Not specified

Chemotherapy

• No prior systemic adjuvant chemotherapy for LCIS

Endocrine therapy

• No prior tamoxifen, raloxifene, or other selective estrogen-receptor modulators
• At least 3 months since prior and no concurrent use of any of the following drugs:
• Estrogen or progesterone replacement therapy
• Oral contraceptives
• Androgens
• Luteinizing hormone-releasing hormone analogs
• Prolactin inhibitors
• Antiandrogens
• Steroids
• No concurrent steroids for asthma

Radiotherapy

• No prior radiotherapy for LCIS

Surgery

• No prior bilateral prophylactic mastectomy
• No prior mastectomy for LCIS

Other

• Concurrent nonhormonal medications allowed
• No concurrent warfarin or cholestyramine
• No prior or concurrent participation in any other cancer prevention study
• Patients treated with placebo on protocol NSABP-P-1 are eligible