Through the study of breast cancer outcomes data, we seek to inform treatment practices and improve patient care for breast cancer. We are currently investigating national as well as institutional level data to 1) characterize practice patterns for patients with ductal carcinoma in situ (DCIS) across the U.S.; 2) understand the implications of new consensus guidelines on margin status for early stage breast cancers from the Society of Surgical Oncology and American Society for Radiation Oncology on reexcision lumpectomy rates for breast conserving surgery, 3) explore the role of racial disparities among breast cancer screening and treatment programs.