OBJECTIVES: I. Determine whether a diet rich in vegetables, fruit, and fiber and low in fat is associated with a longer breast cancer event-free interval in breast cancer survivors. II. Motivate an intervention group of breast cancer survivors to adopt and maintain a dietary pattern that is rich in vegetables, fruit, and fiber and low in fat. III. Demonstrate that the intervention can produce significant changes in circulating carotenoid and estrogen biomarkers compared to a healthy control diet. IV. Test whether the probability of a secondary cancer event is associated with change in self-reported dietary intake, circulating carotenoid concentrations, and circulating estrogen concentrations.

OUTLINE: This is a randomized, multicenter study. Patients are stratified according to age (under 55 vs 55 and over at time of diagnosis), stage of tumor (stage I and at least 1 cm vs stage II/IIIA), and clinical site. Patients are randomized to one of two healthy dietary regimens: Arm I: Patients are taught to follow a dietary pattern that will produce significant changes in circulating carotenoid and estrogen biomarkers. Arm II: Patients are assigned to follow dietary guidelines established by the National Cancer Institute and the USDA. All patients participate in 24 hour dietary recalls, cooking classes, as well as complete several questionnaires, at baseline and then at 12, 24 or 36, 48, and 72 months; a randomly selected 50% sample participate in recall at 6 months. Patients are followed by telephone every 6 months for an average of 6 years.

PROJECTED ACCRUAL: A total of 3,000 women will be accrued for this study within 5 years.

DISEASE CHARACTERISTICS: Primary operable stage I (tumors at least 1 cm), stage II, and stage IIIA invasive breast carcinoma Treatment within the past 4 years by total mastectomy and axillary dissection, or breast sparing surgical removal of cancer with clear macroscopic margins and axillary dissection followed by adjuvant breast radiation No evidence of recurrent disease or new breast cancer since completion of initial local treatment confirmed within the past 6 months by physician evaluation, except stage I mastectomy, for which physician evaluation can be within 1 year prior to randomization Hormone receptor status: Not specified

PATIENT CHARACTERISTICS: Age: 18 to 70 at time of diagnosis Sex: Female Menopausal status: Not specified Performance status: Not specified Life expectancy: At least 10 years (excluding breast cancer) Hematopoietic: Not specified Hepatic: No cirrhosis Renal: Not specified Other: Not pregnant Accessible geographically and by telephone Able to communicate dietary data via 24-hour food recall Able to commit to the intervention schedule No comorbidity requiring a specific diet or taking a medication which contraindicates consuming a high fiber diet (e.g., systemic scleroderma, other digestive malabsorption syndromes, and insulin dependent diabetes) No other primary or recurrent invasive cancer within the past 10 years except nonmelanoma skin cancer or carcinoma in situ of the cervix

PRIOR CONCURRENT THERAPY: Biologic therapy: Not specified Chemotherapy: No concurrent chemotherapy Endocrine therapy: No concurrent estrogen replacement therapy, including vaginal estrogen creams Radiotherapy: See Disease Characteristics Surgery: See Disease Characteristics Other: No concurrent enrollment in another clinical trial that has dietary restrictions or endpoints similar to this study