Omega-3 Fatty Acids in Preventing Breast Cancer in Women at High Risk of Developing Breast Cancer

OBJECTIVES: Primary * Determine the effects of omega-3 fatty acids on mammographic breast density (MBD) in women at high risk of developing breast cancer. Secondary * Determine, preliminarily, the effects of this supplement on cell atypia and breast cell proliferation measured in ductal lavage specimens from these patients. * Determine the effects of this supplement on circulating hormone and growth factor blood levels in these patients. * Determine the effects of this supplement on the expression of estrogen-related proteins found in ductal lavage specimens from these patients. * Determine the effects of this supplement on plasma lipid peroxidation levels in these patients. * Correlate the modifying effect of lipid peroxidation-related genes with MBD in patients treated with this supplement. OUTLINE: This is a randomized, pilot study. Patients are randomized to 1 of 2 treatment arms. * Arm I: Patients receive oral placebo three times daily for 12 months. * Arm II: Patients receive oral omega-3 fatty acids three times daily for 12 months. In both arms, treatment continues in the absence of the development of ductal carcinoma in situ or invasive carcinoma of the breast or unacceptable toxicity. PROJECTED ACCRUAL: A total of 80 patients (40 per treatment arm) will be accrued for this study.