With careful screening most breast cancers can be detected when they are small. Small breast cancers can be treated successfully without removing the entire breast. A lumpectomy of the cancer is performed removing the entire cancer with surrounding normal breast tissue. Radiation therapy over five to six weeks is administered to the remaining breast tissue after a lumpectomy. Before deciding on breast conserving surgery for breast cancer, the following should be carefully discussed with the involved doctors: The cosmetic appearance of the breast when treatment is finished, the risks of radiation treatment, the risk of the cancer growing back in the breast and the option of breast reconstruction after mastectomy.

The pathologist takes the lumpectomy specimen and applies ink to the outside of the tissue to stain the margin. The distance of the cancer cells from the inked margin can then be measured. If cancer cells are at the margin, a re-excision lumpectomy or a mastectomy needs to be considered.