Breast carcinoma remains the most common malignancy and the second leading cause of cancer deaths among adult women in the United States. The benefits of early detection by screening mammography continue to be demonstrated. Fine-needle aspiration biopsy has become established as a highly accurate and cost-effective diagnostic tool that may supplant open surgical biopsy of even nonpalpable breast lesions. The safety and efficacy of breast conservation treatment for early invasive carcinoma continue to be affirmed. Analysis of several issues in management indicate no proven benefit for any different or less aggressive locoregional treatment of early "minimal" or "microinvasive" disease than that applied to later more established forms of invasive breast carcinoma. These frontiers in our understanding of the biology, diagnosis, and treatment of breast carcinoma can best be advanced through scientific investigation of this disease.