This kind of surgery removes one quarter of the breast and is considered to be a breast conserving procedure. It is considered to be a partial mastectomy. Your surgeon will remove the tumor and 2-3 centimeters of breast tissue that surrounds it, to be sure that the margins around the tumor are clear of cancer. Skin that is lying over that quarter of your breast will also be removed, and some of the muscle of the chest wall, beneath the tumor may also need to be taken out. The lymph nodes that are closest to the tumor will be removed and tested for cancer cells, as will the skin and the tissue around the tumor.
A quadrantectomy will result in a change of size and shape of your breast, and after you recover from surgery, you may want to put some additional padding in your bra to even out your appearance. You may wish to have a plastic surgeon remodel the breast into a smaller size with a natural shape, and this is best done before any other treatments, such as radiation or chemotherapy, are done. Radiation will change the texture of the skin in the surgery area, and during chemotherapy your body may not have the resources to heal properly from surgery. The skin at the incision will have a scar, and will change in texture, but if you give the incision good care, it will fade into a small line with time.
If the tumor is larger or is invasive, a mastectomy may be necessary.