Definition and Management of Positive Margins for Invasive Breast Cancer.

Breast-conserving surgery (BCS) followed by radiation therapy is the current standard of care for early stage breast cancer. Successful BCS necessitates complete tumor resection with clear margins at the pathologic assessment of the specimen ("no ink on tumor"). The presence of positive margins warrants additional surgery to obtain negative final margins, which has significant physical, psychological, and financial implications for the patient. The challenge lies in developing accurate real-time intraoperative margin assessment techniques to minimize the presence of "ink on tumor" and the subsequent need for additional surgery.