PRIOR CONCURRENT THERAPY: Biologic therapy: Not specified Chemotherapy: At least 5 years since prior chemotherapy Endocrine therapy: At least 12 months since prior tamoxifen therapy No concurrent estrogen therapy At least 3 months since prior anabolic steroids Radiotherapy: No prior radiotherapy to the chest or breast Surgery: See Disease Characteristics Other: No vitamin A supplementation greater than 25,000 IU At least 12 months since prior retinoid therapy