Arzoxifene or Tamoxifen in Preventing Breast Cancer in Premenopausal Women at High Risk for Breast Cancer

DISEASE CHARACTERISTICS: * Estimated probability of carrying a BRCA1 or BRCA2 mutation ≥ 10% AND meets one of the following criteria: * Participants must have first-degree relatives (FDRs)\* or second-degree relatives (SDRs)\* (with an intervening male relative) with breast or ovarian cancer who satisfy one of the following criteria: * High-risk breast/ovarian cancer (non-Jewish families) * One FDR ≤ 40 years old\*\* diagnosed with breast cancer * At least two FDRs or SDRs diagnosed with breast cancer at ≤ 50 years old OR had bilateral breast cancer * One FDR or one SDR diagnosed with breast cancer at ≤ 50 years old OR had bilateral breast cancer AND one FDR or SDR diagnosed with ovarian cancer * Three FDRs and/or SDRs diagnosed with breast or ovarian cancer (at least one in case of ovarian cancer) * Two FDRs and/or SDRs diagnosed with ovarian cancer * One male FDR or SDR diagnosed with breast cancer and one FDR or SDR (male or female) diagnosed with breast or ovarian cancer * Moderate-risk breast /ovarian cancer (non-Jewish families) * Two FDRs diagnosed with breast cancer with one ≤ 50 years old and/or both \< 60 years old * One FDR and one SDR (mother or sister and maternal aunt or maternal grandmother) diagnosed with breast cancer if the sum of their ages is ≥ 118 years * One FDR and one SDR (mother or sister and paternal aunt or paternal grandmother) diagnosed with breast cancer if the sum of their ages is ≥ 78 years * Two SDRs (both maternal or both paternal) diagnosed with breast cancer if the sum of their ages is ≤ 98 years * One FDR with ovarian cancer * High-risk breast/ovarian cancer (Jewish families ) * At least one FDR or SDR diagnosed with breast cancer at ≤ 50 years old * At least one FDR or SDR diagnosed with ovarian cancer * At least one FDR or SDR diagnosed with breast cancer at any age AND one FDR or SDR diagnosed with breast and/or ovarian cancer * At least one male FDR or SDR diagnosed with breast cancer NOTE: \*FDRs are parents, siblings, and children of the participant; SDRs are aunts, uncles, grandparents, grandchildren, nieces, nephews, or half siblings of the participant NOTE: \*\*Age is approximated to the earliest age possible (e.g., a relative diagnosed in their 40's should be considered 40) * Patterns of cancer cases must all be on the maternal or paternal side of the family * Participants not meeting any of the above FDR or SDR criteria may provide medical documentation stating that they, a FDR, or a SDR carry BRCA1 or BRCA2 mutations * Participants with a prior history of breast cancer are eligible provided they have a remaining breast that has not been irradiated, all therapy for breast cancer was completed more than 2 years ago, and they are premenopausal * No ovarian cyst during screening * No more than 12 months since prior Pap smear with normal cytological results OR human papilloma virus negative if atypical squamous cells of uncertain significance (ASCUS) present * No higher degrees of atypia beyond ASCUS on Pap smear * No known history of osteoporosis (bone mineral density \> 1.5 standard deviations below young adult norms) * Hormone receptor status * Not specified PATIENT CHARACTERISTICS: Menopausal status * Premenopausal, as defined by 1 of the following: * Last menstrual period \< 6 months ago * Less than 45 years old AND underwent partial hysterectomy OR follicle-stimulating hormone within institutional pre-menopausal range within the past 3 months Sex * Female Performance status * ECOG 0-1 Life expectancy * More than 2 years Hematopoietic * WBC ≥ 3,000/mm\^3 * Platelet count ≥ 125,000/mm\^3 * Hemoglobin ≥ 10 g/dL Hepatic * Bilirubin ≤ 1.5 mg/dL * AST \< 2 times upper limit of normal (ULN) * Albumin ≥ 3.0 g/dL * PT/PTT ≤ 1.25 times ULN Renal * Creatinine ≤ 1.5 mg/dL OR * Creatinine clearance ≥ 60 mL/min Cardiovascular * No history of deep venous thrombosis Pulmonary * No history of pulmonary embolism Other * Not pregnant or nursing * Negative pregnancy test * Fertile participants must use effective barrier-method contraception during and for 3 months after completion of study treatment * No other malignancy within the past 2 years except curatively treated basal cell or squamous cell skin cancer or cervical cancer ≤ stage I * No known addiction * Not undergoing treatment for an illicit drug addiction * Willing and able to undergo required study procedures (e.g., research-related breast biopsies) PRIOR CONCURRENT THERAPY: Chemotherapy * More than 2 years since prior chemotherapy Endocrine Therapy * At least 3 months since prior oral contraceptives or intramuscular progestational agent * At least 3 months since prior luteinizing-hormone releasing hormone (LHRH) agonists or antagonists if agent was administered daily or monthly * At least 6 months since prior LHRH agonists or antagonists if agent was administered every 3 months * At least 6 months since prior antiestrogens (e.g., tamoxifen, toremifene, and raloxifene) * No concurrent progestational or contraceptive agents Radiotherapy * See Disease Characteristics * More than 2 years since prior radiotherapy Surgery * No prior prophylactic bilateral mastectomy Other * No concurrent cholestyramine * No concurrent routine warfarin, bromocriptine, or phenobarbital * No other concurrent investigational agents