To ensure all cancer is removed during a surgery, the standard procedure is for the surgeon to include a border of tissue surrounding and beyond the edges of the visible cancerous tumor. This border of tissue is called the surgical margin or margin of resection, and it needs to be examined microscopically by a pathologist to determine if cancer cells are present.

At some point in their lives, approximately 1 in 8 women will develop some type of breast cancer. As this is the second most common cancer among women in the United States, the need for early detection in the most treatable stages of the disease is paramount. One route for early detection is having a mammogram done at regular intervals.