Breast Cancer Lumpectomy Margins

For patients opting to have breast-conserving surgery (also called a “lumpectomy” or “partial mastectomy”) for their breast cancer, it is important that the surgeon remove the entire cancer and a rim of normal breast tissue all the way around the tumor. How much normal tissue must be removed by the surgeon has been the source of some debate.

The American Society of Breast Surgeons, along with other national professional organizations, has stated that as long as there is no invasive breast cancer at the “inked” edge of the tissue already removed by the surgeon, then it is not necessary to remove additional tissue. 

For ductal carcinoma in situ (DCIS), the National Comprehensive Cancer Network has said that removal of additional tissue should be considered when DCIS is found closer than 1 mm from the edge of the removed tissue. Removal of more tissue, however, depends on where the cancer was located and whether there is more tissue that the surgeon can take. For example, sometimes the surgeon has removed all of the tissue down to the muscle or up to the skin; therefore, no more breast tissue can be removed in these directions. 

The breast surgeon will go over the pathology report with the patient, explain the distance of the margins, and discuss whether or not more tissue needs to be taken.


The American Society of Breast Surgeons' Consensus Statement

Icon Breast Cancer Lumpectomy Margins (118.0 KB)