Women who choose a lumpectomy rather than a full mastectomy need radiation treatment following surgery. APBI is designed specifically to treat early stages of breast cancer quickly and efficiently by delivering radiation directly into the tumor cavity from inside the body. Our radiation oncologists work directly with breast surgeons to treat the cavity after surgery. Radiation therapy is usually performed one to four weeks after a lumpectomy. The temporary devices for example MammoSite or Savi applicator is placed in the cavity by the breast surgeon.