This year, more than 213,000 American women will learn they have breast cancer. Many women with early stage cancer prefer to have a lumpectomy, where only the cancerous lump is surgically removed, followed by radiation therapy and possibly chemotherapy. With a lumpectomy, the surgeon removes the tumor along with some healthy, non-cancerous tissue nearby. Doctors then examine it under a microscope. If the outside of the tumor, or margin, is free of cancer, it’s considered to be a negative margin. If the outside of the tumor has cancer cells present, it’s considered a positive margin. When it’s unclear, or a very small distance, doctors call it a close margin. Women with a positive or close margin often require more surgery to make sure all the cancer is removed. This surgery is called a re-excision. Most patients with close or positive margins would be advised to undergo re-excision.